Dimethyl 2,6,8-trimethyl-1,2-dihydroquinoline-2,4-dicarboxylate.

The title compound, C(16)H(19)NO(4), the hydrogenated ring adopts a twisted conformation. In the crystal, inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric R(2) (2)(10) dimers. These dimers are further connected via inter-molecular N-H⋯O hydrogen bonds, forming infinite double chains along [001].

Related literature

For the preparation of 1,2-dihydro­quinoline, see: Edwards et al. (1998 ▶); Yan et al. (2004 ▶); Petasis & Butkevich (2009 ▶); Johnson et al. (1989 ▶); Waldmann et al. (2008 ▶); Rueping & Gültekin (2009 ▶). For the biological activity of dihydro­quinolines, see: Elmore et al. (2001 ▶); Dillard et al. (1973 ▶); Muren & Weissmann (1971 ▶). For the preparation of quinolines, see: Dauphinee & Forrest (1978 ▶); Yan et al. (2004 ▶); Tom & Ruel (2001 ▶); Tokuyama et al. (2001 ▶); Sarma & Prajapati (2008 ▶); Martinez et al. (2008 ▶); Huang et al. (2009 ▶); Katritzky et al. (1996 ▶). For the biological activity of quinolines, see: Hamann et al. (1998 ▶); He et al. (2003 ▶); LaMontagne et al. (1989 ▶). For graph-set analysis, see: Bernstein et al. (1995 ▶). For ring puckering parameters, see: Cremer & Pople (1975 ▶).

Experimental

Crystal data

C16H19NO4

M = 289.33

Monoclinic,

a = 7.7944 (5) Å

b = 23.4621 (8) Å

c = 8.2551 (5) Å

β = 93.729 (5)°

V = 1506.44 (14) Å3

Z = 4

Mo Kα radiation

μ = 0.09 mm−1

T = 294 K

0.45 × 0.35 × 0.05 mm

Data collection

Nicolet P3 diffractometer

3188 measured reflections

2971 independent reflections

1999 reflections with I > 2σ(I)

R int = 0.030

3 standard reflections every 50 reflections intensity decay: 2%

Refinement

R[F 2 > 2σ(F 2)] = 0.056

wR(F 2) = 0.144

S = 1.07

2971 reflections

244 parameters

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.19 e Å−3

Δρmin = −0.21 e Å−3

Data collection: XSCANS (Siemens, 1996 ▶); cell refinement: XSCANS; data reduction: SHELXTL (Sheldrick, 2008 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: WinGX publication routines (Farrugia, 1999 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053681004153X/su2218sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S160053681004153X/su2218Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C16H19NO4	F(000) = 616
Mr = 289.33	Dx = 1.276 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 26 reflections
a = 7.7944 (5) Å	θ = 12–14°
b = 23.4621 (8) Å	µ = 0.09 mm−1
c = 8.2551 (5) Å	T = 294 K
β = 93.729 (5)°	Plate, pale yellow
V = 1506.44 (14) Å3	0.45 × 0.35 × 0.05 mm
Z = 4

Nicolet P3 diffractometer	Rint = 0.030
Radiation source: fine-focus sealed tube	θmax = 26.0°, θmin = 1.7°
graphite	h = 0→9
Wyckoff–Scan scans	k = 0→28
3188 measured reflections	l = −10→10
2971 independent reflections	3 standard reflections every 50 reflections
1999 reflections with I > 2σ(I)	intensity decay: 2%

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.056	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.144	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	w = 1/[σ2(Fo2) + (0.0504P)2 + 0.6624P] where P = (Fo2 + 2Fc2)/3
2971 reflections	(Δ/σ)max < 0.001
244 parameters	Δρmax = 0.19 e Å−3
0 restraints	Δρmin = −0.21 e Å−3

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > 2sigma(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

	x	y	z	Uiso*/Ueq
O1	0.7764 (3)	0.59692 (11)	−0.3063 (2)	0.0640 (6)
O2	0.5173 (2)	0.61471 (9)	−0.2180 (2)	0.0502 (5)
O3	1.1234 (3)	0.60687 (11)	0.3726 (3)	0.0738 (7)
O4	1.1641 (2)	0.56175 (9)	0.1411 (2)	0.0539 (6)
N1	0.7690 (3)	0.60501 (9)	0.3076 (3)	0.0393 (5)
H1	0.792 (4)	0.6030 (12)	0.417 (4)	0.054 (9)*
C1	0.7476 (3)	0.61554 (11)	−0.0238 (3)	0.0334 (5)
C2	0.8247 (3)	0.56972 (11)	0.0436 (3)	0.0352 (6)
H2	0.849 (3)	0.5376 (11)	−0.018 (3)	0.035 (7)*
C3	0.8769 (3)	0.56643 (10)	0.2214 (3)	0.0353 (6)
C4	0.7347 (3)	0.65906 (11)	0.2432 (3)	0.0341 (5)
C5	0.7101 (3)	0.70451 (12)	0.3481 (3)	0.0415 (6)
H5	0.733 (3)	0.6993 (10)	0.464 (3)	0.033 (6)*
C6	0.6669 (3)	0.75784 (12)	0.2865 (3)	0.0447 (7)
C7	0.6494 (4)	0.76513 (12)	0.1202 (4)	0.0466 (7)
H7	0.620 (3)	0.8011 (12)	0.074 (3)	0.046 (8)*
C8	0.6763 (3)	0.72106 (11)	0.0118 (3)	0.0403 (6)
C9	0.7161 (3)	0.66663 (11)	0.0741 (3)	0.0342 (5)
C10	0.6878 (3)	0.60882 (11)	−0.1978 (3)	0.0389 (6)
C11	0.4423 (5)	0.60908 (19)	−0.3831 (4)	0.0605 (9)
H111	0.475 (5)	0.6429 (16)	−0.448 (4)	0.084 (12)*
H112	0.485 (5)	0.5743 (16)	−0.428 (4)	0.077 (12)*
H113	0.322 (6)	0.6056 (16)	−0.371 (5)	0.095 (13)*
C12	0.8522 (4)	0.50594 (13)	0.2861 (4)	0.0500 (7)
H121	0.873 (4)	0.5072 (12)	0.407 (4)	0.057 (9)*
H123	0.734 (4)	0.4934 (13)	0.252 (4)	0.064 (9)*
H122	0.926 (4)	0.4786 (14)	0.238 (4)	0.070 (10)*
C13	1.0681 (3)	0.58165 (11)	0.2556 (3)	0.0376 (6)
C14	1.3481 (4)	0.57041 (17)	0.1667 (5)	0.0720 (10)
H14A	1.4029	0.5604	0.0698	0.108*
H14B	1.3924	0.5468	0.2549	0.108*
H14C	1.3709	0.6097	0.1924	0.108*
C15	0.6472 (6)	0.80746 (16)	0.4010 (5)	0.0637 (9)
H151	0.582 (6)	0.7969 (18)	0.496 (5)	0.108 (15)*
H152	0.588 (6)	0.840 (2)	0.347 (5)	0.115 (16)*
H153	0.754 (6)	0.8168 (18)	0.450 (5)	0.109 (16)*
C16	0.6685 (4)	0.73525 (12)	−0.1667 (3)	0.0536 (8)
H16A	0.7586	0.7154	−0.2172	0.080*
H16B	0.6828	0.7756	−0.1802	0.080*
H16C	0.5591	0.7238	−0.2163	0.080*

	U11	U22	U33	U12	U13	U23
O1	0.0579 (13)	0.0996 (18)	0.0346 (11)	0.0201 (12)	0.0036 (9)	−0.0042 (11)
O2	0.0363 (10)	0.0755 (14)	0.0376 (10)	−0.0025 (9)	−0.0070 (8)	0.0008 (9)
O3	0.0470 (12)	0.106 (2)	0.0664 (15)	−0.0009 (12)	−0.0122 (11)	−0.0370 (14)
O4	0.0303 (9)	0.0749 (14)	0.0564 (12)	−0.0054 (9)	0.0028 (8)	−0.0166 (10)
N1	0.0414 (12)	0.0463 (13)	0.0301 (11)	0.0068 (10)	0.0026 (9)	0.0048 (10)
C1	0.0252 (11)	0.0435 (14)	0.0316 (12)	−0.0012 (10)	0.0020 (9)	−0.0001 (10)
C2	0.0292 (12)	0.0376 (14)	0.0385 (14)	−0.0003 (10)	−0.0001 (10)	−0.0036 (11)
C3	0.0321 (13)	0.0362 (13)	0.0372 (13)	0.0009 (10)	−0.0006 (10)	0.0014 (11)
C4	0.0245 (11)	0.0414 (14)	0.0365 (12)	0.0002 (10)	0.0029 (9)	0.0015 (11)
C5	0.0391 (14)	0.0533 (17)	0.0326 (14)	0.0000 (12)	0.0064 (11)	−0.0036 (12)
C6	0.0367 (14)	0.0442 (16)	0.0538 (17)	0.0013 (12)	0.0085 (12)	−0.0081 (13)
C7	0.0454 (15)	0.0377 (15)	0.0563 (18)	0.0041 (12)	0.0013 (13)	0.0031 (13)
C8	0.0360 (13)	0.0437 (15)	0.0411 (14)	0.0009 (11)	0.0015 (11)	0.0032 (12)
C9	0.0282 (11)	0.0398 (14)	0.0344 (13)	0.0003 (10)	0.0016 (10)	−0.0004 (10)
C10	0.0385 (13)	0.0449 (15)	0.0330 (13)	0.0026 (11)	−0.0014 (11)	−0.0008 (11)
C11	0.056 (2)	0.078 (3)	0.0452 (18)	−0.0146 (19)	−0.0160 (15)	0.0065 (18)
C12	0.0518 (18)	0.0420 (17)	0.0555 (19)	−0.0044 (14)	−0.0012 (15)	0.0088 (14)
C13	0.0371 (13)	0.0382 (14)	0.0365 (13)	0.0019 (11)	−0.0047 (10)	0.0003 (11)
C14	0.0314 (15)	0.102 (3)	0.083 (2)	−0.0042 (17)	0.0006 (15)	−0.008 (2)
C15	0.068 (2)	0.055 (2)	0.070 (2)	0.0065 (18)	0.014 (2)	−0.0184 (18)
C16	0.066 (2)	0.0452 (17)	0.0492 (17)	0.0033 (14)	0.0014 (14)	0.0094 (13)

O1—C10	1.199 (3)	C6—C15	1.513 (4)
O2—C10	1.336 (3)	C7—H7	0.95 (3)
O2—C11	1.454 (3)	C8—C7	1.392 (4)
O3—C13	1.189 (3)	C8—C16	1.508 (4)
O4—C13	1.328 (3)	C9—C8	1.404 (3)
O4—C14	1.450 (3)	C11—H111	1.00 (4)
N1—C3	1.453 (3)	C11—H112	0.96 (4)
N1—C4	1.394 (3)	C11—H113	0.95 (4)
N1—H1	0.91 (3)	C12—H121	1.01 (3)
C1—C2	1.335 (3)	C12—H122	0.97 (3)
C1—C9	1.475 (3)	C12—H123	0.99 (3)
C1—C10	1.490 (3)	C14—H14A	0.9600
C2—H2	0.94 (3)	C14—H14B	0.9600
C3—C2	1.499 (3)	C14—H14C	0.9600
C3—C12	1.533 (4)	C15—H151	0.99 (4)
C3—C13	1.541 (3)	C15—H153	0.93 (5)
C4—C5	1.395 (4)	C15—H152	0.98 (5)
C4—C9	1.405 (3)	C16—H16A	0.9600
C5—H5	0.97 (2)	C16—H16B	0.9600
C6—C5	1.384 (4)	C16—H16C	0.9600
C6—C7	1.381 (4)
C10—O2—C11	116.3 (2)	O1—C10—C1	125.8 (2)
C13—O4—C14	116.4 (2)	O2—C10—C1	110.9 (2)
C3—N1—H1	111.9 (19)	O2—C11—H111	109 (2)
C4—N1—C3	118.9 (2)	O2—C11—H112	108 (2)
C4—N1—H1	116.5 (18)	O2—C11—H113	104 (2)
C2—C1—C9	120.9 (2)	H111—C11—H112	111 (3)
C2—C1—C10	114.9 (2)	H113—C11—H111	114 (3)
C9—C1—C10	124.1 (2)	H113—C11—H112	110 (3)
C1—C2—C3	122.4 (2)	C3—C12—H121	107.6 (17)
C1—C2—H2	121.5 (15)	C3—C12—H122	112.1 (19)
C3—C2—H2	116.2 (15)	C3—C12—H123	108.2 (18)
N1—C3—C2	108.6 (2)	H121—C12—H122	112 (3)
N1—C3—C12	108.4 (2)	H121—C12—H123	112 (2)
N1—C3—C13	110.5 (2)	H123—C12—H122	105 (3)
C2—C3—C12	110.9 (2)	O3—C13—O4	124.2 (2)
C2—C3—C13	111.4 (2)	O3—C13—C3	124.0 (2)
C12—C3—C13	107.0 (2)	O4—C13—C3	111.8 (2)
N1—C4—C5	119.3 (2)	O4—C14—H14A	109.5
N1—C4—C9	119.9 (2)	O4—C14—H14B	109.5
C5—C4—C9	120.7 (2)	O4—C14—H14C	109.5
C4—C5—H5	119.5 (15)	H14A—C14—H14B	109.5
C6—C5—C4	120.2 (2)	H14A—C14—H14C	109.5
C6—C5—H5	120.1 (15)	H14B—C14—H14C	109.5
C5—C6—C15	119.9 (3)	C6—C15—H151	112 (3)
C7—C6—C5	118.9 (3)	C6—C15—H152	112 (3)
C7—C6—C15	121.2 (3)	C6—C15—H153	109 (3)
C6—C7—C8	122.5 (3)	H151—C15—H152	108 (4)
C6—C7—H7	121.0 (16)	H151—C15—H153	102 (4)
C8—C7—H7	116.5 (16)	H153—C15—H152	113 (4)
C7—C8—C9	118.6 (2)	C8—C16—H16A	109.5
C7—C8—C16	117.8 (2)	C8—C16—H16B	109.5
C9—C8—C16	123.5 (2)	C8—C16—H16C	109.5
C4—C9—C1	115.5 (2)	H16A—C16—H16B	109.5
C8—C9—C1	125.4 (2)	H16A—C16—H16C	109.5
C8—C9—C4	119.0 (2)	H16B—C16—H16C	109.5
O1—C10—O2	123.2 (2)
C11—O2—C10—O1	−3.4 (4)	N1—C3—C13—O3	23.5 (4)
C11—O2—C10—C1	180.0 (3)	N1—C3—C13—O4	−158.4 (2)
C14—O4—C13—O3	2.1 (4)	C2—C3—C13—O3	144.2 (3)
C14—O4—C13—C3	−176.1 (2)	C2—C3—C13—O4	−37.6 (3)
C4—N1—C3—C2	−43.0 (3)	C12—C3—C13—O3	−94.4 (3)
C4—N1—C3—C12	−163.6 (2)	C12—C3—C13—O4	83.7 (3)
C4—N1—C3—C13	79.5 (3)	N1—C4—C5—C6	−176.6 (2)
C3—N1—C4—C5	−148.5 (2)	C9—C4—C5—C6	0.0 (4)
C3—N1—C4—C9	34.8 (3)	N1—C4—C9—C1	−4.2 (3)
C9—C1—C2—C3	2.5 (4)	N1—C4—C9—C8	178.1 (2)
C10—C1—C2—C3	−173.5 (2)	C5—C4—C9—C1	179.2 (2)
C2—C1—C9—C4	−14.1 (3)	C5—C4—C9—C8	1.5 (4)
C2—C1—C9—C8	163.4 (2)	C7—C6—C5—C4	−0.3 (4)
C10—C1—C9—C4	161.5 (2)	C15—C6—C5—C4	−177.6 (3)
C10—C1—C9—C8	−21.0 (4)	C5—C6—C7—C8	−1.0 (4)
C2—C1—C10—O1	−58.1 (4)	C15—C6—C7—C8	176.3 (3)
C2—C1—C10—O2	118.4 (2)	C9—C8—C7—C6	2.6 (4)
C9—C1—C10—O1	126.0 (3)	C16—C8—C7—C6	−174.9 (3)
C9—C1—C10—O2	−57.5 (3)	C1—C9—C8—C7	179.8 (2)
N1—C3—C2—C1	24.7 (3)	C1—C9—C8—C16	−2.9 (4)
C12—C3—C2—C1	143.8 (3)	C4—C9—C8—C7	−2.7 (4)
C13—C3—C2—C1	−97.2 (3)	C4—C9—C8—C16	174.5 (2)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1i	0.91 (3)	2.30 (3)	3.190 (3)	166 (3)
C2—H2···O4ii	0.94 (3)	2.54 (3)	3.444 (3)	162 (2)

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯O1i	0.91 (3)	2.30 (3)	3.190 (3)	166 (3)
C2—H2⋯O4ii	0.94 (3)	2.54 (3)	3.444 (3)	162 (2)

Symmetry codes: (i) ; (ii) .