Copper Salts/TBAB-Catalyzed Chemo- and Regioselective β-C(sp3)-H Acyloxylation of Aliphatic Amides.

An efficient Cu(II)-catalyzed and tetrabutylammonium bromide (TBAB)-promoted strategy for highly regioselective and chemoselective C(sp3)-H acyloxylation of aliphatic amides is described. Acyloxylation occurs selectively at the β position with a broad substrate scope of carboxylic acids and aliphatic amides and good functional group compatibility. Notably, the competing reaction of intramolecular dehydrogenative amidation and intermolecular acyloxylation could be efficiently controlled by the amount of copper salt and the addition of TBAB. The intramolecular dehydrogenative amidation product was obtained in high yield when the amount of copper salts was increased. However, when TBAB was used as an additive, a preference for acyloxylation over intramolecular amidation was observed and the acyloxylated products were obtained in good yield. Preliminary studies were carried out to gain insights into the mechanism.

Introduction

Transition metal-catalyzed C(sp2)–H functionalization via a directing group auxiliary has been extensively developed in the past decade.[1] In contrast to the direct functionalization of the C(sp2)–H bond, direct functionalization of an unactivated C(sp3)–H bond has been less researched because of the high bond dissociation energy of the C(sp3)–H bond and lack of π electrons that can readily interact with transition metals.[2] Directing group-assisted transition metal-catalyzed C(sp3)–H functionalization has emerged as a powerful method to overcome the tremendous challenges.[3] Recently, various precious metal-catalyzed C(sp3)–H activations have been extensively explored with the assistance of a monodentate or bidentate directing group.[4] Although significant advances have been made with precious metal catalysts, the development of low-cost and environmentally benign first-row transition metals such as Fe, Co, Ni, and Cu is still in high demand.[5]

8-Aminoquinoline developed by Daugulis’ group has been proven to be a powerful bidentate auxiliary in transition metal-catalyzed direct C–H bond activation,[3a,3b,6] and it has been used in stereoselective as well as regioselective C–H functionalization reactions.[7] Palladium-catalyzed and nickel-catalyzed C(sp3)–H functionalization by using an 8-aminoquinoline bidentate auxiliary has been applied extensively,[4c,5b,8,9] whereas the chelation-assisted examples involving copper catalysts are rare. Recently, Kanai, You, and Ge have demonstrated the copper-catalyzed intramolecular amidation of C(sp3)–H bonds,[10] and the reaction provides a protocol for functionalization at β-C(sp3)–H bonds in a highly regioselective manner. Ge also reported copper-promoted cross-dehydrogenative coupling of aliphatic amides and polyfluoroarenes by using an 8-aminoquinoline as the directing group.[11] Intermolecular amination of β-C(sp3)–H bonds was reported by Qin[5f] and Yang[12] by using simple alkylamines as the amino source.

The development of C–O bond formation reactions has greatly accelerated in recent years following landmark reports on Pd-catalyzed C(sp3)–H acetoxylation reactions by the Sanford[13] and Yu[14] laboratories using different organic oxidants.[15,16] In 2013, Roane and Daugulis reported the first copper-catalyzed 8-aminoquinoline-directed C–H to C–O transformation.[17] Recently, the copper-promoted direct acetoxylation and acyloxylation of β-C(sp3)–H bonds with the assistance of an 8-aminoquinoline bidentate directing group have also been reported.[18] However, a large amount of oxidants, the limited substrate scope, and harsh reaction conditions have prevented the synthetic applications. Continuing our research efforts in the development of novel copper-catalyzed C–H acyloxylation,[19] herein we report a highly efficient method for copper-catalyzed and Bu4N+-promoted regioselective and chemoselective β-C(sp3)–H acyloxylation of aliphatic amides with carboxylic acids including aromatic acids, cinnamic acids, heterocyclic carboxylic acids, and aliphatic acids (Scheme b).

Scheme 1

(a,b) Copper-Catalyzed β-C(sp3)–H Acyloxylation and Amidation of Aliphatic Amides

Results and Discussion

On the basis of our previous direct acyloxylation of C(sp2)–H bonds (Scheme ), we began our study by conducting β-C(sp3)–H acyloxylation of 2,2-dimethyl-N-(quinolin-8-yl)butanamide substrate 1a with benzoic acid in the presence of CuBr (30 mol %) and Ag2CO3 (2 equiv) in toluene/dimethylformamide (DMF) at 140 °C under air for 12 h. We were pleased to observe that acyloxylation of β-C(sp3)–H bonds afforded a mixture of monoacyloxylated products 3aa and diacyloxylated products 3aa′ in 1:1 ratio with a combined yield of 41% and the intramolecular amidated product 4a in 18% yield, and the acyloxylation of γ-methyl group C–H bonds with benzoic acid was not observed. Interestingly, the yield of the intramolecular amidated product was increased with an increase in the amount of CuBr (Table , entries 1–3) and afforded 4a in 80% yield in the absence of benzoic acid by using stoichiometric copper salts (entry 4). To our surprise, employing phase-transfer catalysts such as tetrabutylammonium bromide (TBAB) as an additive led to a dramatic improvement in the yield of the acyloxylated product 3a and absolutely inhibited the intramolecular amidated reaction (entry 5). Encouraged by this result, a series of copper salts such as CuI, CuBr2, CuCl2·2H2O, Cu(OAc)2·H2O, Cu(OCOCF3)2, and CuSO4·5H2O were then screened, which showed that the reaction could be catalyzed by either a copper(II) or copper(I) and Cu(OCOCF3)2 proved to be the best catalyst (entries 6–11). The absence of a copper catalyst or an oxidant fails to generate the desired products, which indicated that the copper catalyst and oxidant played indispensable roles in this reaction (entries 12 and 13). Various oxidants, such as AgOAc, AgOCOCF3, and K2S2O8, were tested, and Ag2CO3 was determined to be especially effective (entries 14–16). A brief survey of reaction media showed that the reaction in toluene/DMF gave the best result, whereas toluene, DMF, and chlorobenzene only led to low yields (see the Supporting Information for more details). Instead of TBAB, the use of some other additives such as tetrabutylammonium iodide (TBAI) or tetrabutylammonium chloride (TBAC) had no obvious influence on the reaction efficiency (entries 17 and 18, see the Supporting Information for more details). When the reaction was performed at 130 and 150 °C, 3a was isolated in 52 and 72% yield (entries 19 and 20). Further investigation showed that a similar yield could be obtained under Ar atmosphere (entry 21). Herein, we chose entry 20 as the optimized reaction conditions.

Table 1

Optimization of Reaction Conditionsa

			yield (%)b
entry	catalyst (mol %)	additive (equiv)	3aa	3aa′	4a
1	CuBr (30)		22	19	18
2	CuBr (50)		13	25	38
3	CuBr (100)		trace	34	58
4c	CuBr (100)				80
5	CuBr (30)	TBAB	27	33	Trace
6	CuI (30)	TBAB	25	14	Trace
7	CuBr2 (30)	TBAB	31	12	Trace
8	CuCl2·2H2O (30)	TBAB	28	35	Trace
9	Cu(OAc)2·H2O (30)	TBAB	23	27	Trace
10	Cu(OCOCF3)2 (30)	TBAB	28	40	Trace
11	CuSO4·5H2O (30)	TBAB	30	36	Trace
12		TBAB
13d	Cu(OCOCF3)2 (30)	TBAB
14e	Cu(OCOCF3)2 (30)	TBAB	24	trace	Trace
15f	Cu(OCOCF3)2 (30)	TBAB	17	trace	Trace
16g	Cu(OCOCF3)2 (30)	TBAB
17	Cu(OCOCF3)2 (30)	TBAI	27	40	trace
18	Cu(OCOCF3)2 (30)	TBAC	26	43	trace
19h	Cu(OCOCF3)2 (30)	TBAB	31	21	trace
20i	Cu(OCOCF3)2 (30)	TBAB	26	46	trace
21i,j	Cu(OCOCF3)2 (30)	TBAB	31	40	trace

Reaction conditions: 1a (0.1 mmol), 2a (0.2 mmol), Ag2CO3 (2 equiv), additive (1 equiv), solvent (2 mL): toluene/DMF (1:1), in air.

Isolated yield.

Without 2a, 8 h.

Without Ag2CO3.

AgOAc (2 equiv).

AgOCOCF3 (2 equiv).

K2S2O8 (2 equiv).

130 °C.

150 °C.

Under Ar atmosphere.

Reaction conn class="Chemical">ditions: 1a (0.1 mmol), 2a (0.2 mmol), Ag2CO3 (2 equiv), additive (1 equiv), solvent (2 mL): toluene/DMF (1:1), in air.

Isolated yieln class="Chemical">d.

Under n class="Chemical">Ar atmosphere.

With an optimized catalytic system in hand, we investigated the scope of this acyloxylation reaction by using a series of acids. As shown in Table , substitution patterns and electronic properties of the phenyl ring of the benzoic acids and cinnamic acids had no obvious influence on the reaction efficiency (3aa–3aj, 3am–3ap). A range of benzoic acids bearing electron-donating and electron-withdrawing groups at either the 2-, 3-, or 4-position of the aromatic ring underwent the desired reaction smoothly to give the corresponding products in moderate yield (3ab–3ad, 3af–3ah). Notably, 2-naphthoic acid, thiophene-2-carboxylic acid, and aliphatic acids were also well tolerated and gave the desired product in moderate yield (3ak, 3al, 3aq, and 3ar).

Table 2

Acyloxylation of Aliphatic Amides with Acids 2a

Reaction conditions: 1a (0.1 mmol), 2 (0.2 mmol), Cu(OCOCF3)2 (30 mol %), Ag2CO3 (2 equiv), TBAB (1 equiv), solvent (2 mL): toluene/DMF (1:1), in air.

Reaction conn class="Chemical">ditions: 1a (0.1 mmol), 2 (0.2 mmol), Cu(OCOCF3)2 (30 mol %), Ag2CO3 (2 equiv), TBAB (1 equiv), solvent (2 mL): toluene/DMF (1:1), in air.

To further explore the generality of this protocol, we investigated the scope of aliphatic amides with benzoic acid. Although Cu(OCOCF3)2 exhibited considerable reactivity with CuSO4·5H2O (Table ), its applicability to other aliphatic amides was unsatisfactory. Therefore, we choose CuSO4·5H2O as the catalyst to investigate the substrate scope (Table ). A high selectivity of the β-methyl groups over γ- or δ-methyl was observed and methylene or benzene C–H bonds were not acyloxylated. Interestingly, the acyloxylation of aliphatic amide 1b showed significant electronic effects. Benzoic acid with an electron-donating group exhibited excellent reactivity rather than an electron-withdrawing substituent on the para-position of the aryl ring (3bb and 3bc). We were pleased to found that a wide variety of aliphatic amides bearing both linear (3ba–3ja) and cyclic chains (3ka and 3la) were compatible with this protocol. However, the acyloxylation of 1-methyl-N-(quinolin-8-yl)cyclohexane-1-carboxamide 1o was not observed because of the steric effect, and the spiro-β-lactam 4o was obtained.

Table 3

Substrate Scope of Aliphatic Amidesa

1 (0.1 mmol), 2a (0.2 mmol), CuSO4·5H2O (30 mol %), Ag2CO3 (2 equiv), TBAC (1 equiv), solvent (2 mL): toluene/DMF (1:1), 150 °C, in air.

1 (0.1 mmol), 2a (0.2 mmol), CuSO4·5n class="Chemical">H2O (30 mol %), Ag2CO3 (2 equiv), TBAC (1 equiv), solvent (2 mL): toluene/DMF (1:1), 150 °C, in air.

Then, we investigated the effects of the directing group on the efficiency of the acyloxylation reaction (Scheme ). No reaction occurred when amide 5a or 6a was used as the substrate, indicating that the presence of a bidentate directing group is crucial for the C–H bond activation and the formation of a five-membered ring intermediate is favorable in cyclometalation step.

Scheme 2

Effects of the Directing Group

To gain insights into the reaction pathway of copper-catalyzed acyloxylation, a series of additional experiments were carried out as shown in Scheme . The addition of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) in the control experiment essentially suppressed the reaction, and only a trace amount of the desired product 3aa was detected when the amount of TEMPO was increased to 3 equiv (Scheme , eq 1). These results suggested that the reaction probably involves a radical pathway. The deuterium-labeling experiments were carried out to further explore the reaction mechanism. It was noticed that there was no apparent H/D exchange in this process and the result suggested the C–H bond metalation step to be not reversible in nature (Scheme , eq 2). A kinetic isotopic effect (KIE) experiment was also conducted and the KIE value was calculated to be 2.8, indicating that the C–H cleavage was probably involved in the rate-determining step of the reaction (Scheme , eq 3). However, the role of TBAB is still not clear; the exact reaction mechanism remains uncertain at present.

Scheme 3

Radical and Deuterium-Labeling Experiments

Conclusions

In conclusion, we have demonstrated the copper(II)/Bu4N+-catalyzed β-C(sp3)–H acyloxylation of aliphatic amides. A high regioselectivity of the β-methyl groups over γ- or δ-methyl and methylene was observed. This method by using the catalytic amount of copper and Bu4N+ could effectively reduce the procedure of C(sp3)–N bond formation. This protocol exhibits a wide substrate scope of carboxylic acids and aliphatic amides and good functional group compatibility, providing an operationally simple approach for the formation of C(sp3)–O bond and C(sp3)–N bond.

Experimental Section

General Information

All starting materials and reagents were commercially available and used directly without further purification. All aliphatic amides were prepared according to the literature procedures.[12,20] All known products gave satisfactory analytical data by NMR spectra, corresponding to the reported literature values. In addition, unknown compounds were confirmed by high-resolution mass spectra (HRMS). Melting points were determined using X-4 micro melting point apparatus and are uncorrected. NMR spectra were recorded at room temperature on a Bruker Avance-300, Bruker Avance-400, and Bruker Avance-500 at 300, 400, and 500 MHz with tetramethylsilane (TMS) as an internal standard. Chemical shifts are given in δ relative to TMS; the coupling constants J are given in hertz. HRMS were recorded on Agilent 6200 LC/MS TOF using electrospray ionization (ESI) in positive mode.

General Procedure for Copper-Catalyzed C(sp3)–H Acyloxylation

To a 10 mL reaction tube were added amide 1a (24.2 mg, 0.1 mmol), benzoic acid (24.4 mg, 0.2 mmol), Cu(OCOCF3)2 (8.7 mg, 30 mol %) or CuSO4·5H2O (7.5 mg, 30 mol %), Ag2CO3 (55.1 mg, 2 equiv), TBAB (32.2 mg, 1 equiv) or TBAC (27.8 mg, 1 equiv), and toluene/DMF (1 mL/1 mL) in air. The mixture was stirred at 150 °C for 12 h. The reaction mixture was then cooled to room temperature, diluted with ethyl acetate, and quenched with saturated sodium chloride. The aqueous phase was extracted with ethyl acetate (3 × 10 mL). The organic layer was dried over Na2SO4. After concentration, the resulting residue was purified by flash chromatography on silica gel with petroleum ether/ethyl acetate (20:1) as the eluent to afford the product.

Characterization Data of Products

2-Methyl-2-(quinolin-8-ylcarbamoyl)butylbenzoate 3aa(13)

Compounn class="Chemical">d 3aa was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3aa as a yellow liquid (9.4 mg, 26%). (Rf = 0.57, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.50 (s, 1H), 8.15 (d, J = 8.1 Hz, 1H), 8.08 (d, J = 7.5 Hz, 2H), 7.65–7.46 (m, 3H), 7.41 (dd, J = 8.1, 4.2 Hz, 1H), 7.37–7.27 (m, 2H), 4.65–4.54 (m, 1H), 4.53–4.43 (m, 1H), 2.16–1.95 (m, 1H), 1.92–1.74 (m, 1H), 1.53 (s, 3H), 1.04 (t, J = 7.2 Hz, 3H). 13C NMR (125 MHz, CDCl3): δ 173.6, 166.3, 148.2, 138.7, 136.3, 134.5, 133.0, 129.9, 129.8, 128.3, 127.9, 127.4, 121.6, 116.6, 69.8, 47.7, 29.4, 19.5, 8.7. HRMS (ESI): calcd for C22H23N2O3 [M + H]+, 363.1708; found, 363.1701.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diyldibenzoate 3aa′

Compounn class="Chemical">d 3aa′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3aa′ as a white solid (22.2 mg, 46%). mp = 142.5–143.7 °C. (Rf = 0.42, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.69 (s, 1H), 8.82 (d, J = 6.3 Hz, 1H), 8.29 (d, J = 3.0 Hz, 1H), 8.19–7.99 (m, 5H), 7.67–7.46 (m, 4H), 7.45–7.28 (m, 5H), 4.82 (s, 4H), 2.14 (q, J = 7.2 Hz, 2H), 1.12 (t, J = 7.2 Hz, 3H). 13C NMR (125 MHz, CDCl3): δ 170.7, 166.2, 148.1, 138.6, 136.3, 134.3, 133.2, 129.8, 129.6, 128.4, 127.9, 127.4, 121.8, 121.6, 116.9, 65.6, 51.0, 25.3, 8.6. HRMS (ESI): calcd for C29H27N2O5 [M + H]+, 483.1920; found, 483.1919.

3-Ethyl-3-methyl-1-(quinolin-8-yl)azetidin-2-one 4a(11)

Compounn class="Chemical">d 4a was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 4a as a yellow liquid (19.2 mg, 80%). (Rf = 0.61, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 8.80 (d, J = 2.1 Hz, 1H), 8.49 (dd, J = 5.4, 3.0 Hz, 1H), 8.10 (d, J = 8.1 Hz, 1H), 7.59–7.43 (m, 2H), 7.38 (dd, J = 8.1, 3.9 Hz, 1H), 4.48–4.34 (m, 1H), 4.32–4.18 (m, 1H), 1.91–1.73 (m, 2H), 1.44 (s, 3H), 1.07 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 173.4, 148.4, 135.9, 135.1, 129.0, 126.7, 122.7, 121.2, 119.4, 58.1, 55.8, 27.8, 19.2, 9.1. HRMS (ESI): calcd for C15H17N2O [M + H]+, 241.1341; found, 241.1340.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-4-methylbenzoate 3ab

Compounn class="Chemical">d 3ab was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ab as a yellow liquid (10.9 mg, 29%). (Rf = 0.50, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.50 (s, 1H), 8.83 (d, J = 5.4 Hz, 1H), 8.65–8.52 (m, 1H), 8.15 (d, J = 7.5 Hz, 1H), 7.96 (d, J = 7.8 Hz, 2H), 7.61–7.47 (m, 2H), 7.45–7.34 (m, 1H), 7.12 (d, J = 7.8 Hz, 2H), 4.64–4.53 (m, 1H), 4.52–4.14 (m, 1H), 2.36 (s, 3H), 2.13–1.96 (m, 1H), 1.91–1.72 (m, 1H), 1.52 (s, 3H), 1.04 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 172.6, 165.4, 147.1, 142.6, 137.6, 135.3, 133.5, 128.8, 128.0, 126.9, 126.4, 126.2, 120.5, 115.7, 68.6, 46.7, 28.4, 20.6, 18.5, 7.7. HRMS (ESI): calcd for C23H25N2O3 [M + H]+, 377.1865; found, 377.1857.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(4-methylbenzoate) 3ab′

Compounn class="Chemical">d 3ab′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ab′ as a white solid (20.4 mg, 40%). mp = 73.8–75.9 °C. (Rf = 0.38, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.67 (s, 1H), 8.82 (dd, J = 6.3, 1.5 Hz, 1H), 8.40–8.30 (m, 1H), 8.13 (d, J = 7.5 Hz, 1H), 7.96 (d, J = 7.8 Hz, 4H), 7.61–7.45 (m, 2H), 7.43–7.31 (m, 1H), 7.16 (d, J = 7.5 Hz, 4H), 4.80 (s, 4H), 2.38 (s, 6H), 2.12 (q, J = 7.2 Hz, 2H), 1.10 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 170.8, 166.3, 148.1, 143.9, 138.6, 136.3, 134.3, 129.9, 129.1, 127.9, 127.4, 126.9, 121.8, 121.6, 116.9, 65.4, 51.1, 25.3, 21.7, 8.6. HRMS (ESI): calcd for C31H31N2O5 [M + H]+, 511.2233; found, 511.2227.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-3-methylbenzoate 3ac

Compounn class="Chemical">d 3ac was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ac as a yellow liquid (10.9 mg, 29%). (Rf = 0.37, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.51 (s, 1H), 8.83 (dd, J = 6.6, 1.2 Hz, 1H), 8.61–8.52 (m, 1H), 8.15 (d, J = 8.1 Hz, 1H), 7.87 (d, J = 7.5 Hz, 1H), 7.82 (s, 1H), 7.60–7.46 (m, 2H), 7.45–7.36 (m, 1H), 7.35–7.27 (m, 1H), 7.24–7.15 (m, 1H), 4.62–4.52 (m, 1H), 4.51–4.42 (m, 1H), 2.21 (s, 3H), 2.13–1.97 (m, 1H), 1.90–1.75 (m, 1H), 1.53 (s, 3H), 1.04 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 173.6, 166.5, 148.2, 138.8, 138.0, 136.3, 134.5, 133.8, 130.3, 129.9, 128.2, 127.9, 127.4, 126.9, 121.5, 116.5, 69.8, 47.8, 29.3, 21.1, 19.5, 8.7. HRMS (ESI): calcd for C23H25N2O3 [M + H]+, 377.1865; found, 377.1858.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(3-methylbenzoate) 3ac′

Compounn class="Chemical">d 3ac′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ac′ as a white solid (20.4 mg, 40%). mp = 73.6–74.4 °C. (Rf = 0.28, petroleum ether/ethyl acetate = 6/1). 1H NMR (500 MHz, CDCl3): δ 10.72 (s, 1H), 8.84 (d, J = 6.5 Hz, 1H), 8.34–8.26 (m, 1H), 8.15 (d, J = 8.0 Hz, 1H), 7.88 (d, J = 7.0 Hz, 2H), 7.84 (s, 2H), 7.60–7.49 (m, 2H), 7.41–7.30 (m, 3H), 7.29–7.21 (m, 2H), 4.81 (s, 4H), 2.27 (s, 6H), 2.14 (q, J = 7.0 Hz, 2H), 1.11 (t, J = 7.0 Hz, 3H). 13C NMR (100 MHz, CDCl3): δ 170.7, 166.4, 148.2, 138.7, 138.1, 136.2, 134.4, 133.9, 130.3, 129.6, 128.3, 127.9, 127.4, 127.0, 121.8, 121.6, 116.9, 65.6, 51.1, 25.3, 21.1, 8.6. HRMS (ESI): calcd for C31H31N2O5 [M + H]+, 511.2233; found, 511.2228.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-2-methylbenzoate 3ad

Compounn class="Chemical">d 3ad was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ad as a white solid (9.0 mg, 24%). mp = 63.8–65.0 °C. (Rf = 0.50, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.48 (s, 1H), 8.82 (d, J = 5.4 Hz, 1H), 8.62–8.47 (m, 1H), 8.14 (d, J = 7.8 Hz, 1H), 7.95 (d, J = 7.2 Hz, 1H), 7.61–7.46 (m, 2H), 7.45–7.28 (m, 2H), 7.23–7.13 (m, 1H), 7.13–7.01 (m, 1H), 4.66–4.52 (m, 1H), 4.52–4.39 (m, 1H), 2.55 (s, 3H), 2.16–1.95 (m, 1H), 1.91–1.73 (m, 1H), 1.54 (s, 3H), 1.04 (t, J = 6.9 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 173.6, 167.3, 148.2, 140.4, 138.7, 136.2, 134.5, 132.0, 131.6, 130.9, 129.3, 127.9, 127.4, 125.6, 121.5, 116.5, 69.9, 47.7, 29.5, 21.9, 19.5, 8.7. HRMS (ESI): calcd for C23H25N2O3 [M + H]+, 377.1865; found, 377.1868.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(2-methylbenzoate) 3ad′

Compounn class="Chemical">d 3ad′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ad′ as a white solid (20.9 mg, 41%). mp = 123.1–125.4 °C. (Rf = 0.43, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.65 (s, 1H), 8.81 (d, J = 5.1 Hz, 1H), 8.27 (d, J = 2.7 Hz, 1H), 8.12 (d, J = 7.5 Hz, 1H), 7.97 (d, J = 7.5 Hz, 2H), 7.61–7.45 (m, 2H), 7.44–7.29 (m, 3H), 7.25–7.17 (m, 2H), 7.17–7.06 (m, 2H), 4.78 (s, 4H), 2.57 (s, 6H), 2.12 (q, J = 7.2 Hz, 2H), 1.11 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 170.8, 167.0, 148.1, 140.6, 136.2, 134.3, 132.2, 131.7, 130.9, 129.0, 127.9, 127.4, 125.7, 121.8, 121.6, 116.9, 65.4, 51.0, 25.4, 21.9, 8.5. HRMS (ESI): calcd for C23H25N2O3 [M + H]+, 511.2233; found, 511.2230.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-4-methoxybenzoate 3ae

Compounn class="Chemical">d 3ae was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ae as a yellow liquid (10.6 mg, 27%). (Rf = 0.40, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.50 (s, 1H), 8.83 (d, J = 6.6 Hz, 1H), 8.59 (d, J = 3.3 Hz, 1H), 8.15 (d, J = 8.1 Hz, 1H), 8.03 (d, J = 7.8 Hz, 2H), 7.59–7.46 (m, 2H), 7.41 (dd, J = 8.1, 4.2 Hz, 1H), 6.81 (d, J = 8.4 Hz, 2H), 4.60–4.50 (m, 1H), 4.50–4.42 (m, 1H), 3.81 (s, 3H), 2.13–1.96 (m, 1H), 1.90–1.72 (m, 1H), 1.51 (s, 3H), 1.03 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 173.2, 165.5, 162.8, 147.6, 138.2, 135.7, 134.0, 131.8, 131.3, 127.4, 126.9, 121.8, 121.0, 116.1, 113.0, 69.0, 54.9, 47.2, 28.9, 19.0, 8.2. HRMS (ESI): calcd for C23H25N2O3 [M + H]+, 393.1814; found, 393.1818.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(4-methoxybenzoate) 3ae′

Compounn class="Chemical">d 3ae′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ae′ as a white solid (20.1 mg, 37%). mp = 126.5–128.1 °C. (Rf = 0.13, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.61 (s, 1H), 8.75 (dd, J = 6.6, 1.8 Hz, 1H), 8.35–8.23 (m, 1H), 8.05 (dd, J = 8.1, 1.2 Hz, 1H), 7.95 (d, J = 8.7 Hz, 4H), 7.57–7.38 (m, 2H), 7.29 (dd, J = 8.1, 4.2 Hz, 1H), 6.76 (d, J = 8.7 Hz, 4H), 4.70 (s, 4H), 3.75 (s, 6H), 2.03 (q, J = 7.2 Hz, 2H), 1.03 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 169.9, 164.9, 162.5, 147.1, 137.6, 135.2, 133.3, 130.9, 126.9, 126.4, 121.1, 120.8, 120.6, 115.9, 112.6, 64.3, 54.4, 50.1, 24.3, 7.5. HRMS (ESI): calcd for C31H31N2O7 [M + H]+, 543.2131; found, 543.2127.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-3-chlorobenzoate 3af

Compounn class="Chemical">d 3af was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3af as a yellow liquid (7.9 mg, 20%). (Rf = 0.47, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.47 (s, 1H), 8.82 (d, J = 6.6 Hz, 1H), 8.67–8.59 (m, 1H), 8.16 (d, J = 8.4 Hz, 1H), 7.98 (s, 1H), 7.93 (d, J = 7.5 Hz, 1H), 7.60–7.36 (m, 4H), 7.33–7.19 (m, 1H), 4.63–4.53 (m, 1H), 4.52–4.43 (m, 1H), 2.16–1.97 (m, 1H), 1.91–1.73 (m, 1H), 1.54 (s, 3H), 1.05 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 172.3, 164.1, 147.3, 137.7, 135.3, 133.4, 133.3, 132.0, 130.6, 128.7, 128.6, 126.9, 126.4, 120.6, 120.6, 115.6, 69.2, 46.7, 28.3, 18.4, 7.6. HRMS (ESI): calcd for C22H22N2O3Cl [M + H]+, 397.1319; found, 397.1314.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(3-chlorobenzoate) 3af′

Compounn class="Chemical">d 3af′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3af′ as a white solid (19.8 mg, 36%). mp = 66.5–67.7 °C. (Rf = 0.23, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.66 (s, 1H), 8.82 (dd, J = 6.0, 2.7 Hz, 1H), 8.42 (d, J = 3.0 Hz, 1H), 8.16 (d, J = 6.9 Hz, 1H), 8.00 (s, 2H), 7.94 (d, J = 7.8 Hz, 2H), 7.62–7.45 (m, 4H), 7.40 (dd, J = 8.1, 4.2 Hz, 1H), 7.34–7.27 (m, 2H), 4.82 (s, 4H), 2.12 (q, J = 7.2 Hz, 2H), 1.12 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 169.4, 163.9, 147.2, 135.5, 133.5, 133.1, 132.2, 130.3, 128.8, 128.7, 126.9, 126.4, 121.0, 120.6, 116.1, 64.9, 50.1, 24.3, 7.5. HRMS (ESI): calcd for C29H25N2O5Cl2 [M + H]+, 551.1140; found, 551.1140.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-2-chlorobenzoate 3ag

Compounn class="Chemical">d 3ag was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ag as a yellow liquid (8.3 mg, 21%). (Rf = 0.25, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.43 (s, 1H), 8.81 (d, J = 6.9 Hz, 1H), 8.60 (d, J = 2.4 Hz, 1H), 8.14 (d, J = 8.4 Hz, 1H), 7.85 (d, J = 7.5 Hz, 1H), 7.61–7.46 (m, 2H), 7.45–7.30 (m, 3H), 7.22–7.10 (m, 1H), 4.70–4.59 (m, 1H), 4.55–4.44 (m, 1H), 2.13–1.95 (m, 1H), 1.90–1.72 (m, 1H), 1.56 (s, 3H), 1.04 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 172.4, 164.4, 147.1, 137.7, 135.3, 133.4, 132.9, 131.8, 131.6, 130.9, 130.0, 128.7, 126.9, 126.4, 125.5, 120.5, 115.5, 69.5, 46.7, 28.4, 18.4, 7.6. HRMS (ESI): calcd for C22H22N2O3Cl [M + H]+, 397.1319; found, 397.1314.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(2-chlorobenzoate) 3ag′

Compounn class="Chemical">d 3ag′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ag′ as a white solid (16.5 mg, 30%). mp = 133.2–134.0 °C. (Rf = 0.17, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.56 (s, 1H), 8.79 (dd, J = 6.3, 1.8 Hz, 1H), 8.37 (d, J = 3.0 Hz, 1H), 8.13 (d, J = 7.8 Hz, 1H), 7.88 (d, J = 7.5 Hz, 2H), 7.62–7.48 (m, 2H), 7.47–7.30 (m, 5H), 7.30–7.16 (m, 2H), 4.97–4.72 (m, 4H), 2.12 (q, J = 7.5 Hz, 2H), 1.11 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 169.3, 164.3, 147.1, 135.2, 133.2, 132.9, 131.8, 130.9, 130.1, 128.5, 126.8, 126.3, 125.6, 120.8, 120.6, 115.8, 64.8, 49.9, 24.2, 7.4. HRMS (ESI): calcd for C29H25N2O5Cl2 [M + H]+, 551.1140; found, 551.1135.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-4-chlorobenzoate 3ah

Compounn class="Chemical">d 3ah was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ah as a white solid (9.5 mg, 24%). mp = 65.6–67.1 °C. (Rf = 0.50, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.46 (s, 1H), 8.82 (d, J = 4.5 Hz, 1H), 8.62 (d, J = 2.7 Hz, 1H), 8.17 (d, J = 8.1 Hz, 1H), 7.99 (d, J = 8.1 Hz, 2H), 7.63–7.48 (m, 2H), 7.48–7.39 (m, 1H), 7.37–7.21 (m, 2H), 4.68–4.53 (m, 1H), 4.52–4.41 (m, 1H), 2.14–1.94 (m, 1H), 1.95–1.72 (m, 1H), 1.52 (s, 3H), 1.04 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 173.4, 165.4, 148.2, 139.4, 138.7, 136.4, 134.4, 131.2, 128.6, 128.4, 128.0, 127.5, 121.6, 116.6, 70.1, 47.8, 29.3, 19.4, 8.7. HRMS (ESI): calcd for C22H22N2O3Cl [M + H]+, 397.1319; found, 397.1313.

Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(4-chlorobenzoate) 3ah′

Compounn class="Chemical">d 3ah′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ah′ as a white solid (22.0 mg, 40%). mp = 91.2–92.3 °C. (Rf = 0.38, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.62 (s, 1H), 8.81 (dd, J = 6.0, 2.7 Hz, 1H), 8.40 (dd, J = 4.2, 1.2 Hz, 1H), 8.17 (dd, J = 8.4, 1.5 Hz, 1H), 7.99 (d, J = 8.7 Hz, 4H), 7.58–7.51 (m, 2H), 7.45–7.37 (m, 1H), 7.33 (d, J = 8.4 Hz, 4H), 4.80 (s, 4H), 2.10 (q, J = 7.5 Hz, 2H), 1.11 (t, J = 7.5 Hz, 3H). 13C NMR (125 MHz, CDCl3): δ 170.4, 165.3, 148.2, 139.7, 138.6, 136.4, 134.2, 131.2, 128.8, 128.1, 128.0, 127.5, 122.0, 121.7, 117.0, 65.7, 51.2, 25.4, 8.5. HRMS (ESI): calcd for C29H25N2O5Cl2 [M + H]+, 551.1140; found, 551.1147.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-4-bromobenzoate 3ai

Compounn class="Chemical">d 3ai was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ai as a yellow liquid (11.0 mg, 25%). (Rf = 0.54, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.44 (s, 1H), 8.81 (d, J = 4.8 Hz, 1H), 8.64 (d, J = 3.0 Hz, 1H), 8.19 (d, J = 8.1 Hz, 1H), 7.91 (d, J = 8.1 Hz, 2H), 7.63–7.39 (m, 4H), 4.64–4.54 (m, 1H), 4.52–4.40 (m, 1H), 2.15–1.93 (m, 1H), 1.92–1.74 (m, 1H), 1.53 (s, 3H), 1.04 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 172.5, 164.6, 147.0, 135.7, 133.3, 130.6, 130.3, 127.8, 127.1, 127.0, 126.5, 120.7, 120.6, 116.0, 109.0, 69.1, 46.8, 28.3, 18.4, 7.7. HRMS (ESI): calcd for C22H22N2O3Br [M + H]+, 441.0814; found, 441.0808.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(4-bromobenzoate) 3ai′

Compounn class="Chemical">d 3ai′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ai′ as a white solid (17.2 mg, 27%). mp = 87.8–89.1 °C. (Rf = 0.28, petroleum ether/ethyl acetate = 6/1). 1H NMR (500 MHz, CDCl3): δ 10.64 (s, 1H), 8.82 (dd, J = 6.0, 2.0 Hz, 1H), 8.41 (d, J = 3.0 Hz, 1H), 8.19 (d, J = 8.0 Hz, 1H), 7.91 (d, J = 8.5 Hz, 4H), 7.61–7.53 (m, 2H), 7.50 (d, J = 8.5 Hz, 4H), 7.47–7.41 (m, 1H), 4.80 (s, 4H), 2.11 (q, J = 7.5 Hz, 2H), 1.11 (t, J = 7.5 Hz, 3H). 13C NMR (125 MHz, CDCl3): δ 170.5, 165.4, 148.0, 138.3, 136.7, 134.0, 131.7, 131.3, 128.4, 127.9, 127.5, 122.1, 121.7, 117.2, 104.9, 65.6, 51.0, 25.2, 8.5. HRMS (ESI): calcd for C29H25N2O5Br2 [M + H]+, 639.0129; found, 639.0125.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-4-fluorobenzoate 3aj

Compounn class="Chemical">d 3aj was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3aj as a white solid (10.3 mg, 27%). mp = 76.8–78.4 °C. (Rf = 0.36, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.47 (s, 1H), 8.83 (d, J = 6.6 Hz, 1H), 8.62 (d, J = 3.6 Hz, 1H), 8.17 (d, J = 8.4 Hz, 1H), 8.13–7.90 (m, 2H), 7.63–7.49 (m, 2H), 7.48–7.40 (m, 1H), 7.10–6.91 (m, 2H), 4.66–4.53 (m, 1H), 4.52–4.40 (m, 1H), 2.16–1.96 (m, 1H), 1.91–1.72 (m, 1H), 1.53 (s, 3H), 1.04 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 173.5, 165.8 (1JC–F = 252.8 Hz), 165.3, 148.1, 138.7, 136.4, 134.4, 132.4 (3JC–F = 9.0 Hz), 128.0, 127.5, 126.2, 121.6, 116.7, 115.4 (2JC–F = 21.8 Hz), 70.0, 47.7, 29.3, 19.4, 8.7. HRMS (ESI): calcd for C22H22N2O3F [M + H]+, 381.1614; found, 381.1610.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(4-fluorobenzoate) 3aj′

Compounn class="Chemical">d 3aj′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3aj′ as a white solid (18.1 mg, 35%). mp = 136.7–138.1 °C. (Rf = 0.21, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.64 (s, 1H), 8.82 (d, J = 5.7 Hz, 1H), 8.38 (d, J = 3.0 Hz, 1H), 8.17 (d, J = 8.1 Hz, 1H), 8.14–7.94 (m, 4H), 7.63–7.50 (m, 2H), 7.46–7.37 (m, 1H), 7.32–6.95 (m, 4H), 4.80 (s, 4H), 2.12 (q, J = 7.2 Hz, 2H), 1.12 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 170.5, 165.9 (1JC–F = 253.5 Hz), 165.2, 148.1, 138.6, 136.4, 134.2, 132.4 (3JC–F = 9.0 Hz), 127.9, 127.4, 125.9 (4JC–F = 3.0 Hz), 121.8 (2JC–F = 21.8 Hz), 117.0, 115.6 (2JC–F = 21.8 Hz), 65.6, 51.1, 25.3, 8.6. HRMS (ESI): calcd for C29H25N2O5F2 [M + H]+, 519.1731; found, 519.1729.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-2-naphthoate 3ak

Compounn class="Chemical">d 3ak was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ak as a yellow liquid (8.2 mg, 20%). (Rf = 0.25, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.57 (s, 1H), 8.86 (d, J = 5.7 Hz, 1H), 8.57 (s, 1H), 8.53 (d, J = 2.4 Hz, 1H), 8.14 (d, J = 7.5 Hz, 1H), 8.08 (d, J = 7.8 Hz, 1H), 7.87–7.72 (m, 2H), 7.68–7.48 (m, 4H), 7.47–7.40 (m, 1H), 7.40–7.30 (m, 1H), 4.71–4.61 (m, 1H), 4.60–4.50 (m, 1H), 2.19–1.99 (m, 1H), 1.95–1.75 (m, 1H), 1.58 (s, 3H), 1.07 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 172.6, 165.4, 147.2, 137.7, 135.2, 134.4, 133.5, 131.3, 130.3, 128.2, 127.2, 127.0, 126.9, 126.6, 126.4, 126.1, 125.5, 124.3, 120.5, 115.5, 69.0, 46.8, 28.3, 18.5, 7.7. HRMS (ESI): calcd for C26H25N2O3 [M + H]+, 413.1865; found, 413.1860.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(2-naphthoate) 3ak′

Compounn class="Chemical">d 3ak′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ak′ as a white solid (22.1 mg, 38%). mp = 153.6–155.3 °C. (Rf = 0.18, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.82 (s, 1H), 8.89 (d, J = 6.9 Hz, 1H), 8.60 (s, 2H), 8.22 (d, J = 3.0 Hz, 1H), 8.16–8.02 (m, 3H), 7.88–7.72 (m, 4H), 7.72–7.63 (m, 2H), 7.61–7.49 (m, 4H), 7.48–7.38 (m, 2H), 7.32–7.26 (m, 1H), 4.94 (s, 4H), 2.21 (q, J = 7.5 Hz, 2H), 1.18 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 170.8, 166.4, 148.2, 138.6, 136.3, 135.6, 134.4, 132.3, 131.4, 129.3, 128.3, 128.2, 127.9, 127.7, 127.5, 126.9, 126.6, 125.3, 121.9, 121.6, 117.0, 66.0, 51.2, 25.5, 8.7. HRMS (ESI): calcd for C37H31N2O5 [M + H]+, 583.2233; found, 583.2239.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butylthiophene-2-carboxylate 3al

Compounn class="Chemical">d 3al was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3al as a white solid (9.6 mg, 26%). mp = 54.1–55.9 °C. (Rf = 0.40, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.45 (s, 1H), 8.83 (dd, J = 6.9, 1.5 Hz, 1H), 8.65 (d, J = 3.0 Hz, 1H), 8.15 (d, J = 8.1 Hz, 1H), 7.84 (d, J = 3.0 Hz, 1H), 7.61–7.46 (m, 3H), 7.46–7.37 (m, 1H), 7.09–6.96 (m, 1H), 4.61–4.53 (m, 1H), 4.52–4.43 (m, 1H), 2.11–1.94 (m, 1H), 1.89–1.75 (m, 1H), 1.52 (s, 3H), 1.03 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 173.4, 162.0, 148.2, 138.7, 136.3, 134.5, 133.7, 132.6, 127.9, 127.7, 127.4, 121.6, 116.6, 69.8, 47.8, 29.4, 19.5, 8.7. HRMS (ESI): calcd for C20H21N2O3S [M + H]+, 369.1273; found, 369.1271.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(thiophene-2-carboxylate) 3al′

Compounn class="Chemical">d 3al′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3al′ as a white solid (16.3 mg, 33%). mp = 114.1–115.3 °C. (Rf = 0.12, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.63 (s, 1H), 8.80 (dd, J = 6.3, 2.1 Hz, 1H), 8.46 (d, J = 2.7 Hz, 1H), 8.15 (d, J = 8.1 Hz, 1H), 7.87 (d, J = 3.0 Hz, 2H), 7.70–7.45 (m, 4H), 7.44–7.32 (m, 1H), 7.15–6.98 (m, 2H), 4.78 (s, 4H), 2.08 (q, J = 7.5 Hz, 2H), 1.10 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 170.4, 161.7, 148.1, 138.6, 136.3, 134.3, 133.9, 133.2, 132.9, 127.8, 127.4, 121.8, 121.6, 116.9, 65.3, 51.1, 25.2, 8.5. HRMS (ESI): calcd for C25H23N2O5S2 [M + H]+, 495.1048; found, 495.1040.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butylcinnamate 3am

Compounn class="Chemical">d 3am was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3am as a yellow liquid (11.3 mg, 29%). (Rf = 0.26, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.51 (s, 1H), 8.84 (d, J = 6.9 Hz, 1H), 8.74 (d, J = 4.2 Hz, 1H), 8.15 (d, J = 8.1 Hz, 1H), 7.69 (d, J = 15.9 Hz, 1H), 7.61–7.47 (m, 2H), 7.47–7.27 (m, 6H), 6.54 (d, J = 16.2 Hz, 1H), 4.57–4.44 (m, 1H), 4.43–4.28 (m, 1H), 2.09–1.90 (m, 1H), 1.85–1.67 (m, 1H), 1.48 (s, 3H), 1.02 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 172.6, 165.7, 147.2, 144.2, 137.7, 135.3, 133.6, 133.3, 129.3, 127.8, 127.0, 126.5, 120.5, 116.8, 115.6, 68.3, 46.6, 28.4, 18.3, 7.6. HRMS (ESI): calcd for C24H25N2O3 [M + H]+, 389.1865; found, 389.1859.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diyl(2E,2′E)-bis(3-phenylacrylate) 3am′

Compounn class="Chemical">d 3am′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3am′ as a yellow liquid (11.2 mg, 21%). (Rf = 0.28, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.73 (s, 1H), 8.85 (dd, J = 6.6, 1.5 Hz, 1H), 8.66 (d, J = 3.0 Hz, 1H), 8.16 (d, J = 8.1 Hz, 1H), 7.74 (d, J = 15.9 Hz, 2H), 7.61–7.49 (m, 2H), 7.48–7.27 (m, 11H), 6.55 (d, J = 16.2 Hz, 2H), 4.67 (s, 4H), 2.03 (q, J = 7.5 Hz, 2H), 1.08 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 169.8, 165.5, 147.3, 144.5, 137.7, 135.4, 133.5, 133.2, 129.4, 127.9, 127.1, 127.0, 126.5, 120.8, 120.6, 116.6, 115.9, 64.2, 49.8, 24.3, 7.5. HRMS (ESI): calcd for C33H31N2O5 [M + H]+, 535.2233; found, 535.2226.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl(E)-3-(p-tolyl)acrylate 3an

Compounn class="Chemical">d 3an was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3an as a white solid (10.5 mg, 26%). mp = 62.9–63.5 °C. (Rf = 0.30, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.52 (s, 1H), 8.84 (dd, J = 7.2, 1.5 Hz, 1H), 8.74 (d, J = 2.7 Hz, 1H), 8.15 (d, J = 7.2 Hz, 1H), 7.67 (d, J = 15.9 Hz, 1H), 7.59–7.46 (m, 2H), 7.44–7.36 (m, 1H), 7.34–7.23 (m, 2H), 7.18–7.08 (m, 2H), 6.50 (d, J = 15.9 Hz, 1H), 4.55–4.43 (m, 1H), 4.41–4.29 (m, 1H), 2.35 (s, 3H), 2.09–1.89 (m, 1H), 1.87–1.67 (m, 1H), 1.48 (s, 3H), 1.02 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 172.7, 165.9, 147.2, 144.2, 139.7, 137.8, 135.3, 133.6, 130.6, 128.5, 127.0, 126.9, 126.4, 120.5, 120.5, 115.7, 115.5, 68.2, 46.6, 28.4, 20.4, 18.3, 7.6. HRMS (ESI): calcd for C25H27N2O3 [M + H]+, 403.2021; found, 403.2020.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diyl(2E,2′E)-bis(3-(p-tolyl)acrylate) 3an′

Compounn class="Chemical">d 3an′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3an′ as a yellow liquid (24.2 mg, 43%). (Rf = 0.21, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.74 (s, 1H), 8.85 (dd, J = 6.6, 1.8 Hz, 1H), 8.66 (dd, J = 3.9, 1.2 Hz, 1H), 8.15 (dd, J = 8.1, 1.2 Hz, 1H), 7.71 (d, J = 16.2 Hz, 2H), 7.60–7.47 (m, 2H), 7.42–7.28 (m, 5H), 7.21–7.06 (m, 4H), 6.51 (d, J = 16.2 Hz, 2H), 4.66 (s, 4H), 2.36 (s, 6H), 2.03 (q, J = 7.5 Hz, 2H), 1.07 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 170.9, 166.8, 148.3, 145.5, 140.9, 138.8, 136.3, 134.6, 131.5, 129.6, 128.2, 128.0, 127.5, 121.7, 121.6, 116.9, 116.5, 65.2, 50.8, 25.3, 21.5, 8.5. HRMS (ESI): calcd for C35H35N2O5 [M + H]+, 563.2546; found, 563.2553.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl(E)-3-(4-chlorophenyl)acrylate 3ao

Compounn class="Chemical">d 3ao was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ao as a yellow liquid (12.7 mg, 30%). (Rf = 0.32, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.48 (s, 1H), 8.84 (d, J = 6.9 Hz, 1H), 8.74 (d, J = 3.0 Hz, 1H), 8.17 (d, J = 8.1 Hz, 1H), 7.60 (d, J = 16.2 Hz, 1H), 7.57–7.48 (m, 2H), 7.47–7.37 (m, 1H), 7.37–7.20 (m, 4H), 8.49 (d, J = 16.2 Hz, 1H), 4.63–4.45 (m, 1H), 4.42–4.25 (m, 1H), 2.14–1.90 (m, 1H), 1.85–1.72 (m, 1H), 1.48 (s, 3H), 1.02 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 173.6, 166.4, 148.2, 143.7, 140.4, 138.8, 136.4, 134.5, 132.8, 129.2, 129.1, 128.0, 127.5, 121.6, 118.5, 116.6, 69.5, 47.7, 29.4, 19.3, 8.6. HRMS (ESI): calcd for C24H24N2O3Cl [M + H]+, 423.1475; found, 423.1470.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diyl(2E,2′E)-bis(3-(4-chlorophenyl)acrylate) 3ao′

Compounn class="Chemical">d 3ao′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ao′ as a white solid (19.9 mg, 33%). mp = 131.9–133.3 °C. (Rf = 0.16, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.68 (s, 1H), 8.84 (dd, J = 6.6, 2.1 Hz, 1H), 8.65 (d, J = 2.7 Hz, 1H), 8.17 (d, J = 7.5 Hz, 1H), 7.66 (d, J = 15.9 Hz, 2H), 7.61–7.49 (m, 2H), 7.46–7.27 (m, 9H), 6.51 (d, J = 15.9 Hz, 2H), 4.66 (s, 4H), 2.02 (q, J = 7.5 Hz, 2H), 1.07 (t, J = 7.5 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 170.7, 166.3, 148.2, 144.1, 136.4, 136.4, 134.4, 132.7, 129.3, 129.2, 128.0, 127.5, 121.8, 121.6, 118.1, 116.9, 107.2, 65.2, 50.8, 25.3, 8.5. HRMS (ESI): calcd for C33H29N2O5Cl2 [M + H]+, 603.1453; found, 603.1455.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl(E)-3-(4-bromophenyl)acrylate 3ap

Compounn class="Chemical">d 3ap was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ap as a yellow liquid (11.2 mg, 24%). (Rf = 0.48, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.48 (s, 1H), 8.84 (d, J = 6.9 Hz, 1H), 8.74 (d, J = 2.7 Hz, 1H), 8.17 (d, J = 8.4 Hz, 1H), 7.60 (d, J = 15.9 Hz, 1H), 7.56–7.37 (m, 5H), 7.29–7.19 (m, 2H), 6.50 (d, J = 15.9 Hz, 1H), 4.57–4.44 (m, 1H), 4.42–4.31 (m, 1H), 2.08–1.90 (m, 1H), 1.86–1.69 (m, 1H), 1.48 (s, 3H), 1.02 (t, J = 7.5 Hz, 1H). 13C NMR (75 MHz, CDCl3): δ 173.6, 166.4, 148.2, 143.7, 136.4, 134.5, 133.2, 132.1, 131.4, 129.4, 128.0, 127.5, 124.6, 121.6, 118.6, 116.5, 110.0, 69.5, 47.6, 29.4, 19.3, 8.6. HRMS (ESI): calcd for C24H24N2O3Br [M + H]+, 467.0970; found, 467.0972.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diyl(2E,2′E)-bis(3-(4-bromophenyl)acrylate) 3ap′

Compounn class="Chemical">d 3ap′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ap′ as a white solid (19.3 mg, 28%). mp = 178.3–179.2 °C. (Rf = 0.18, petroleum ether/ethyl acetate = 6/1). 1H NMR (500 MHz, CDCl3): δ 10.69 (s, 1H), 8.85 (d, J = 6.5 Hz, 1H), 8.66 (d, J = 2.5 Hz, 1H), 8.20 (d, J = 7.5 Hz, 1H), 7.65 (d, J = 16.0 Hz, 2H), 7.61–7.54 (m, 2H), 7.48 (d, J = 8.5 Hz, 4H), 7.45–7.40 (m, 1H), 7.33–7.28 (m, 4H), 8.53 (d, J = 16.0 Hz, 2H), 4.73–4.60 (m, 4H), 2.03 (q, J = 7.5 Hz, 2H), 1.07 (t, J = 7.5 Hz, 3H). 13C NMR (100 MHz, CDCl3): δ 170.7, 166.2, 148.3, 144.1, 138.7, 136.5, 134.4, 133.1, 132.2, 129.5, 128.0, 127.5, 124.8, 121.9, 121.7, 118.3, 117.0, 65.3, 50.8, 25.3, 8.5. HRMS (ESI): calcd for C33H29N2O5Br2 [M + H]+, 691.0443; found, 691.0440.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butylisobutyrate 3aq

Compounn class="Chemical">d 3aq was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3aq as a yellow liquid (9.8 mg, 30%). (Rf = 0.46, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.40 (s, 1H), 9.02–8.67 (m, 2H), 8.17 (dd, J = 8.4, 1.2 Hz, 1H), 7.60–7.41 (m, 3H), 4.46–4.33 (m, 1H), 4.29–4.16 (m, 1H), 2.78–2.57 (m, 1H), 2.05–1.85 (m, 1H), 1.81–1.61 (m, 1H), 1.43 (s, 3H), 1.27–1.08 (m, 6H), 0.99 (t, J = 7.5 Hz, 3H). 13C NMR (125 MHz, CDCl3): δ 175.7, 172.6, 147.1, 137.7, 135.4, 133.5, 127.0, 126.4, 120.5, 120.5, 115.6, 67.9, 46.6, 33.0, 28.3, 18.3, 17.9, 7.6. HRMS (ESI): calcd for C19H25N2O3 [M + H]+, 329.1865; found, 329.1863.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(2-methylpropanoate) 3aq′

Compounn class="Chemical">d 3aq′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3aq′ as a yellow liquid (16.6 mg, 40%). (Rf = 0.41, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.48 (s, 1H), 8.91–8.73 (m, 2H), 8.18 (dd, J = 8.1, 1.2 Hz, 1H), 7.62–7.51 (m, 2H), 7.50–7.42 (m, 1H), 4.60–4.46 (m, 2H), 4.46–4.37 (m, 2H), 2.77–2.56 (m, 2H), 1.93 (q, J = 7.5 Hz, 2H), 1.30–1.13 (m, 12H), 1.01 (t, J = 7.5 Hz, 3H). 13C NMR (125 MHz, CDCl3): δ 176.5, 170.7, 148.1, 138.6, 136.4, 134.3, 128.0, 127.4, 121.8, 121.6, 116.9, 64.3, 50.9, 34.0, 25.0, 18.9, 8.3. HRMS (ESI): calcd for C23H31N2O5 [M + H]+, 415.2233; found, 415.2230.

2-Methyl-2-(quinolin-8-ylcarbamoyl)butyl-2-methylbutanoate 3ar

Compounn class="Chemical">d 3ar was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ar as a yellow liquid (10.9 mg, 32%). (Rf = 0.42, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.39 (s, 1H), 8.93–8.69 (m, 2H), 8.17 (d, J = 8.4 Hz, 1H), 7.69–7.36 (m, 3H), 4.58–4.31 (m, 1H), 4.27–4.16 (m, 1H), 2.58–2.39 (m, 1H), 2.06–1.87 (m, 1H), 1.82–1.58 (m, 2H), 1.55–1.46 (m, 1H), 1.44 (s, 3H), 1.17–1.09 (m, 3H), 0.99 (t, J = 7.5 Hz, 3H), 0.84 (t, J = 7.5 Hz, 3H). 13C NMR (125 MHz, CDCl3): δ 175.4, 172.5, 147.1, 137.7, 135.4, 133.5, 127.0, 126.4, 120.5, 120.5, 115.6, 67.9, 46.6, 40.0, 28.2, 25.6, 18.2, 15.4, 10.5, 7.6. HRMS (ESI): calcd for C20H27N2O3 [M + H]+, 343.2021; found, 343.2029.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)propane-1,3-diylbis(2-methylbutanoate) 3ar′

Compounn class="Chemical">d 3ar′ was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ar′ as a yellow liquid (16.4 mg, 37%). (Rf = 0.38, petroleum ether/ethyl acetate = 6/1). 1H NMR (300 MHz, CDCl3): δ 10.46 (s, 1H), 8.93–8.70 (m, 2H), 8.29–8.11 (m, 1H), 7.68–7.41 (m, 3H), 4.66–4.31 (m, 4H), 2.64–2.37 (m, 2H), 1.93 (q, J = 7.5 Hz, 2H), 1.78–1.60 (m, 2H), 1.57–1.40 (m, 2H), 1.25–1.12 (m, 6H), 1.00 (t, J = 7.5 Hz, 3H), 0.86 (t, J = 7.5 Hz, 6H). 13C NMR (125 MHz, CDCl3): δ 176.2, 170.7, 148.1, 138.6, 136.5, 134.3, 127.5, 121.6, 117.0, 64.2, 50.9, 41.0, 26.6, 24.9, 16.5, 11.5, 8.3. HRMS (ESI): calcd for C25H35N2O5 [M + H]+, 443.2545; found, 443.2547.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)butylbenzoate 3ba

Compounn class="Chemical">d 3ba was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ba as a yellow liquid (30.1 mg, 80%). (Rf = 0.60, petroleum ether/ethyl acetate = 4/1). 1H NMR (500 MHz, CDCl3): δ 10.52 (s, 1H), 8.99 (d, J = 7.5 Hz, 1H), 8.36 (dd, J = 2.5, 1.5 Hz, 1H), 8.10 (d, J = 7.5 Hz, 2H), 7.76 (d, J = 8.5 Hz, 2H), 7.41–7.32 (m, 1H), 7.30–7.26 (m, 1H), 7.25–7.21 (m, 1H), 7.17–7.11 (m, 2H), 7.04–6.99 (m, 1H), 4.64 (s, 2H), 1.89 (q, J = 7.5 Hz, 4H), 0.93 (t, J = 7.5 Hz, 6H). 13C NMR (125 MHz, CDCl3): δ 172.1, 165.0, 146.9, 137.7, 133.7, 131.7, 129.1, 128.7, 127.2, 126.9, 126.7, 126.5, 126.4, 120.3, 115.6, 65.1, 49.9, 25.3, 7.3. HRMS (ESI): calcd for C23H25N2O3 [M + H]+, 377.1865; found, 377.1869.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)butyl-4-methoxybenzoate 3bb

Compounn class="Chemical">d 3bb was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3bb as a white solid (30.9 mg, 76%). mp = 75.9–76.7 °C. (Rf = 0.51, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.48 (s, 1H), 8.84 (d, J = 6.9 Hz, 1H), 8.58 (d, J = 2.7 Hz, 1H), 8.15 (d, J = 8.4 Hz, 1H), 8.04 (d, J = 8.7 Hz, 2H), 7.67–7.47 (m, 2H), 7.45–7.34 (m, 1H), 6.84 (d, J = 8.4 Hz, 2H), 4.60 (s, 2H), 3.83 (s, 3H), 1.97 (q, J = 7.5 Hz, 4H), 1.02 (t, J = 7.2 Hz, 6H). 13C NMR (75 MHz, CDCl3): δ 173.5, 166.0, 163.4, 148.2, 138.8, 136.3, 136.2, 134.6, 131.8, 127.9, 127.4, 122.5, 121.5, 116.6, 113.5, 65.9, 55.4, 51.0, 26.2, 8.5. HRMS (ESI): calcd for C24H27N2O4 [M + H]+, 407.1971; found, 407.1976.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)butyl-4-(trifluoromethyl)benzoatem 3bc

Compounn class="Chemical">d 3bc was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3bc as a white solid (18.2 mg, 41%). mp = 82.1–83.7 °C. (Rf = 0.58, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.42 (m, 1H), 8.82 (dd, J = 6.6, 2.1 Hz, 1H), 8.61 (dd, J = 4.5, 1.5 Hz, 1H), 8.24–8.08 (m, 3H), 7.61 (d, J = 8.4 Hz, 2H), 7.56–7.48 (m, 2H), 7.47–7.39 (m, 1H), 4.65 (s, 2H), 1.98 (q, J = 7.5 Hz, 4H), 1.03 (t, J = 7.5 Hz, 6H). 13C NMR (125 MHz, CDCl3): δ 173.1, 165.1, 148.2, 138.7, 136.4, 136.5 (q, 2JC–F = 32.5 Hz), 136.4, 133.3, 130.2, 128.0, 127.5, 125.4 (q, 3JC–F = 3.6 Hz), 123.6 (q, 1JC–F = 271.0 Hz), 121.6, 116.7, 66.7, 51.1, 26.0, 8.5. HRMS (ESI): calcd for C24H24N2O3F3 [M + H]+, 445.1739; found, 445.1742.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)pentylbenzoate 3ca(18b)

Compounn class="Chemical">d 3ca was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ca as a yellow liquid (28.5 mg, 73%). (Rf = 0.63, petroleum ether/ethyl acetate = 4/1). 1H NMR (500 MHz, CDCl3): δ 10.49 (s, 1H), 8.88–8.77 (m, 1H), 8.59–8.48 (m, 1H), 8.16–8.03 (m, 3H), 7.57–7.41 (m, 3H), 4.64 (s, 2H), 2.05–1.95 (m, 2H), 1.92–1.82 (m, 2H), 1.51–1.38 (m, 2H), 1.03 (q, J = 4.5 Hz, 3H), 0.97 (q, J = 4.2 Hz, 3H). 13C NMR (125 MHz, CDCl3): δ 172.4, 165.2, 147.1, 137.7, 135.2, 133.5, 131.9, 129.0, 128.7, 127.3, 126.9, 126.3, 120.5, 120.4, 115.5, 65.4, 49.7, 35.1, 25.7, 16.4, 13.7, 7.5. HRMS (ESI): calcd for C24H27N2O3 [M + H]+, 391.2021; found, 391.2022.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)hexylbenzoate 3da

Compounn class="Chemical">d 3da was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3da as a yellow liquid (26.7 mg, 66%). (Rf = 0.62, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.50 (s, 1H), 8.84 (d, J = 7.2 Hz, 1H), 8.61–8.48 (m, 1H), 8.22–8.00 (m, 3H), 7.63–7.44 (m, 3H), 7.43–7.28 (m, 3H), 4.64 (s, 2H), 2.00 (q, J = 7.5 Hz, 2H), 1.94–1.82 (m, 2H), 1.53–1.29 (m, 4H), 1.04 (t, J = 7.2 Hz, 3H), 0.96–0.81 (m, 3H). 13C NMR (75 MHz, CDCl3): δ 173.4, 166.3, 148.2, 138.8, 136.3, 134.5, 133.0, 130.1, 129.8, 128.3, 127.9, 127.4, 121.5, 121.5, 116.6, 66.5, 50.7, 33.5, 26.8, 26.2, 23.3, 13.9, 8.6. HRMS (ESI): calcd for C25H29N2O3 [M + H]+, 405.2178; found, 405.2183.

2-Ethyl-2-(quinolin-8-ylcarbamoyl)heptylbenzoate 3ea

Compounn class="Chemical">d 3ea was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ea as a yellow liquid (27.2 mg, 65%). (Rf = 0.65, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.48 (s, 1H), 8.82 (dd, J = 6.9, 1.5 Hz, 1H), 8.53 (dd, J = 4.2, 1.5 Hz, 1H), 8.14 (dd, J = 8.4, 1.5 Hz, 1H), 8.11–8.04 (m, 2H), 7.61–7.45 (m, 3H), 7.45–7.31 (m, 3H), 4.63 (s, 2H), 1.99 (q, J = 7.5 Hz, 2H), 1.94–1.82 (m, 2H), 1.55–1.21 (m, 6H), 1.03 (t, J = 7.5 Hz, 3H), 0.85 (t, J = 6.9 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 173.5, 166.3, 148.2, 138.8, 136.3, 134.5, 133.0, 130.1, 129.8, 128.3, 127.9, 127.4, 121.5, 121.4, 116.6, 66.5, 50.7, 33.7, 32.4, 26.8, 23.7, 22.4, 14.0, 8.5. HRMS (ESI): calcd for C26H31N2O3 [M + H]+, 419.2335; found, 419.2340.

2-Propyl-2-(quinolin-8-ylcarbamoyl)pentylbenzoate 3fa

Compounn class="Chemical">d 3fa was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3fa as a yellow liquid (30.3 mg, 75%). (Rf = 0.64, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.49 (s, 1H), 8.82 (dd, J = 7.2, 1.8 Hz, 1H), 8.52 (dd, J = 4.2, 1.5 Hz, 1H), 8.23–8.03 (m, 3H), 7.62–7.44 (m, 3H), 7.43–7.31 (m, 3H), 4.63 (s, 2H), 2.00–1.83 (m, 4H), 1.58–1.35 (m, 4H), 0.97 (t, J = 7.2 Hz, 6H). 13C NMR (75 MHz, CDCl3): δ 173.5, 166.3, 148.2, 138.7, 136.2, 134.5, 133.0, 130.0, 129.8, 128.3, 127.9, 127.4, 121.5, 121.4, 116.6, 66.9, 50.6, 36.6, 17.4, 14.7. HRMS (ESI): calcd for C25H28N2O3 [M + H]+, 405.2178; found, 405.2185.

2-Propyl-2-(quinolin-8-ylcarbamoyl)hexylbenzoate 3ga

Compounn class="Chemical">d 3ga was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ga as a yellow liquid (29.7 mg, 71%). (Rf = 0.65, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.49 (s, 1H), 8.81 (dd, J = 6.9, 1.8 Hz, 1H), 8.52 (dd, J = 4.2, 1.5 Hz, 1H), 8.14 (dd, J = 8.4, 1.5 Hz, 1H), 8.09 (d, J = 7.2 Hz, 2H), 7.59–7.45 (m, 3H), 7.43–7.32 (m, 3H), 4.62 (s, 2H), 1.98–1.81 (m, 4H), 1.52–1.33 (m, 6H), 0.97 (t, J = 7.5 Hz, 3H), 0.93–0.84 (m, 3H). 13C NMR (75 MHz, CDCl3): δ 172.5, 165.3, 147.2, 137.8, 135.2, 133.5, 132.0, 129.1, 128.8, 127.3, 126.9, 126.4, 120.5, 120.4, 115.6, 65.9, 49.5, 35.7, 33.0, 25.2, 22.3, 16.4, 13.7, 12.9. HRMS (ESI): calcd for C26H31N2O3 [M + H]+, 419.2335; found, 419.2341.

2-Propyl-2-(quinolin-8-ylcarbamoyl)heptylbenzoate 3ha

Compounn class="Chemical">d 3ha was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ha as a yellow liquid (30.2 mg, 70%). (Rf = 0.67, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.49 (s, 1H), 8.81 (dd, J = 7.2, 1.5 Hz, 1H), 8.52 (dd, J = 3.9, 0.9 Hz, 1H), 8.21–8.05 (m, 3H), 7.62–7.45 (m, 3H), 7.44–7.30 (m, 3H), 4.62 (s, 2H), 2.07–1.81 (m, 4H), 1.52–1.37 (m, 4H), 1.36–1.23 (m, 4H), 0.97 (t, J = 7.2 Hz, 3H), 0.91–0.77 (m, 3H). 13C NMR (75 MHz, CDCl3): δ 173.5, 166.3, 148.2, 138.8, 136.3, 134.5, 133.0, 130.1, 129.8, 128.3, 127.9, 127.4, 121.5, 121.4, 116.7, 66.9, 50.5, 36.7, 34.3, 32.4, 23.7, 22.4, 17.4, 14.7, 14.0. HRMS (ESI): calcd for C27H33N2O3 [M + H]+, 433.2491; found, 433.2485.

2-Ethyl-4-phenyl-2-(quinolin-8-ylcarbamoyl)butylbenzoate 3ia

Compounn class="Chemical">d 3ia was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ia as a yellow liquid (23.1 mg, 51%). (Rf = 0.57, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.55 (s, 1H), 8.84 (dd, J = 7.2, 1.8 Hz, 1H), 8.54 (dd, J = 4.2, 1.5 Hz, 1H), 8.28–8.04 (m, 3H), 7.63–7.48 (m, 3H), 7.45–7.34 (m, 3H), 7.32–7.10 (m, 5H), 4.73 (s, 2H), 2.94–2.65 (m, 2H), 2.34–2.16 (m, 2H), 2.07 (q, J = 7.2 Hz, 2H), 1.08 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 172.9, 166.3, 148.2, 141.8, 138.7, 136.4, 134.4, 133.1, 129.9, 129.8, 128.4, 127.9, 127.4, 127.4, 125.9, 121.6, 116.8, 116.7, 66.2, 50.8, 36.3, 30.7, 27.1, 8.6. HRMS (ESI): calcd for C29H29N2O3 [M + H]+, 453.2178; found, 453.2184.

2-Benzyl-2-(quinolin-8-ylcarbamoyl)butylbenzoate 3ja

Compounn class="Chemical">d 3ja was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ja as a yellow liquid (26.7 mg, 61%). (Rf = 0.54, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.49 (s, 1H), 8.84 (d, J = 7.2 Hz, 1H), 8.42 (d, J = 2.7 Hz, 1H), 8.22–8.04 (m, 3H), 7.63–7.10 (m, 11H), 4.73–4.42 (m, 2H), 3.51–3.33 (m, 1H), 3.30–3.31 (m, 1H), 2.12–1.82 (m, 2H), 1.09 (t, J = 7.2 Hz, 3H). 13C NMR (75 MHz, CDCl3): δ 172.6, 166.1, 148.1, 138.7, 136.4, 136.2, 134.3, 133.1, 130.2, 129.9, 129.8, 128.3, 127.9, 127.4, 126.7, 121.6, 116.6, 65.9, 51.9, 39.9, 27.0, 8.7. HRMS (ESI): calcd for C28H27N2O3 [M + H]+, 439.2021; found, 439.2025.

(1-(Quinolin-8-ylcarbamoyl)cyclobutyl)methylbenzoate 3ka

Compounn class="Chemical">d 3ka was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3ka as a yellow liquid (20.2 mg, 56%). (Rf = 0.64, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.29 (s, 1H), 8.83 (dd, J = 7.2, 1.5 Hz, 1H), 8.58 (dd, J = 4.2, 1.5 Hz, 1H), 8.22–8.03 (m, 3H), 7.62–7.46 (m, 3H), 7.45–7.37 (m, 1H), 7.35–7.23 (m, 2H), 4.73 (s, 2H), 2.86–2.66 (m, 2H), 2.37–1.93 (m, 4H). 13C NMR (75 MHz, CDCl3): δ 172.9, 165.5, 147.1, 137.6, 135.3, 133.5, 132.0, 128.9, 128.8, 127.2, 126.9, 126.4, 120.5, 115.5, 115.4, 67.4, 47.6, 28.7, 26.4, 14.2. HRMS (ESI): calcd for C22H21N2O3 [M + H]+, 361.1552; found, 361.1555.

(1-(Quinolin-8-ylcarbamoyl)cyclopentyl)methylbenzoate 3la

Compounn class="Chemical">d 3la was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 3la as a white solid (19.8 mg, 53%). mp = 71.9–72.3 °C. (Rf = 0.53, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 10.51 (s, 1H), 8.81 (dd, J = 7.2, 1.5 Hz, 1H), 8.50 (dd, J = 3.9, 1.5 Hz, 1H), 8.22–8.06 (m, 3H), 7.62–7.44 (m, 3H), 7.43–7.28 (m, 3H), 4.54 (s, 2H), 2.53–2.29 (m, 2H), 2.01–1.72 (m, 6H). 13C NMR (75 MHz, CDCl3): δ 174.4, 166.5, 148.1, 138.7, 136.3, 136.3, 134.8, 133.0, 129.9, 129.9, 128.2, 127.9, 127.4, 121.5, 116.5, 68.9, 55.3, 33.6, 25.1. HRMS (ESI): calcd for C23H23N2O3 [M + H]+, 375.1708; found, 375.1712.

2-(Quinolin-8-yl)-2-azaspiro[3.5]nonan-1-one 4o(11)

Compounn class="Chemical">d 4o was prepared according to the general procedure. A purification by flash chromatography in petroleum ether/ethyl acetate = 20/1 gave 4o as a yellow liquid (10.1 mg, 38%). (Rf = 0.63, petroleum ether/ethyl acetate = 4/1). 1H NMR (300 MHz, CDCl3): δ 8.86–8.77 (m, 1H), 8.54–8.44 (m, 1H), 8.10 (dd, J = 8.1, 1.5 Hz, 1H), 7.54–7.45 (m, 2H), 7.43–7.33 (m, 1H), 4.33 (s, 2H), 2.03–1.77 (m, 6H), 1.68–1.34 (m, 4H). 13C NMR (75 MHz, CDCl3): δ 173.6, 148.3, 140.3, 135.9, 135.3, 129.0, 126.8, 122.6, 121.1, 119.3, 59.3, 56.9, 31.2, 25.3, 23.4. HRMS (ESI): calcd for C17H19N2O [M + H]+, 267.1497; found, 267.1494.