Crystal structure of (E)-4-hy-droxy-6-methyl-3-{1-[2-(4-nitro-phen-yl)hydrazinyl-idene]eth-yl}-2H-pyran-2-one.

The title compound, C14H13N3O5 (HMNP), was synthesized by the simple condensation of p-nitro-phenyl-hydrazine with de-hydro-acetic acid (DHA) in a 1:1 molar ratio in ethanol. HMNP has been characterized by using FT-IR, 1H and 13C NMR and UV-Vis spectroscopic and single-crystal X-ray diffraction techniques. The crystal packing reveals strong hydrogen bonds between the NH group and the carbonyl O atom of di-hydro-pyran-one moiety, forming chains along [101]. The thermal stability of the synthesized compound was confirmed by thermogravimetric analysis and it was found to be stable up to 513 K. The UV-Vis spectrum shows the presence of a strong band at λmax 394 nm. 1H NMR and single-crystal X-ray analyses confirmed the presence of the enol form of the ligand and dominance over the keto form. The crystal studied was a non-merohedral twin with the refined ratio of the twin components being 0.3720 (19):0.6280 (19).

Chemical context

For the last several decades, Schiff bases have remained an important and popular area of research for the scientific community due to their simple synthesis, versatility and extensive range of applications (Cozzi, 2004 ▸; Chen et al., 2008 ▸). A number of carbonyl compounds and amines have been utilized for the synthesis of Schiff bases (Zheng et al., 2009 ▸; Hussain et al., 2014 ▸). However, there are only a few reports where de­hydro­acetic acid (DHA) has been used for the preparation of Schiff bases for various applications (Liu et al., 1991 ▸; Luo et al., 1995 ▸). In some cases, DHA-based Schiff bases are used for the synthesis of metal complexes, leading to their utilization in various biomedical applications due to their anti­fungal, anti­bacterial, anti­malarial and anti­cancer activities (Chan & Wong, 1995 ▸; Erkkila et al., 1999 ▸; Ganjali et al., 2007 ▸; Gupta & Sutar, 2008 ▸). In general, the compounds are formed via a condensation product of hydrazine and the respective aldehyde or ketone in a 1:1 molar ratio. Structurally, a Schiff base (also known as an imine or azomethine) is a nitro­gen analogue of an aldehyde or ketone in which the carbonyl group (C=O) has been replaced by an imine or azomethine group.

The reaction between p-nitro­phenyl­hydrazine and de­hydro­acetic acid (DHA) in a 1:1 molar ratio in distilled ethanol afforded the title compound within 4 h. We report herein on its characterization by FT–IR, 1H and 13C NMR and UV–Vis spectroscopic and single-crystal X-ray diffraction techniques.

Structural commentary

The mol­ecular structure of the title compound is shown in Fig. 1 ▸. The dihedral angle between the pyran (O2/C9–C13) and benzene (C1–C6) rings is 12.9 (1)°. The approximate planarity of the entire mol­ecule maybe influenced by an intra­molecular O1—H1⋯N3 hydrogen bond, which forms an S(6) ring.

Figure 1

The mol­ecular structure of the title compound, showing the atom-naming scheme. The displacement ellipsoids are shown at the 50% probability level.

Supra­molecular features

The crystal packing features strong N2—H2⋯O3i hydrogen bonds between the NH group and the Ocarbon­yl atom of the DHA moiety of symmetry-related mol­ecules, creating infinite chains along [101] (see Table 1 ▸ for symmetry code). This Ocarbon­yl atom is also weakly hydrogen bonded to a symmetry-related hydrogen atom (C5–H5⋯O3i), forming a bifurcated N—H,C—H⋯O hydrogen bond (Fig. 2 ▸). In a similar fashion, the O2 atom of the pyran ring forms a weak hydrogen bond to the methyl hydrogen of an adjacent mol­ecule (C7—H7A⋯O2i). The chains are arranged in a herringbone pattern in the three-dimensional structure (Fig. 3 ▸).

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1⋯N3	0.90 (2)	1.64 (2)	2.4760 (18)	154 (2)
N2—H2⋯O3i	0.85 (2)	2.00 (2)	2.8361 (19)	165.2 (19)
C5—H5⋯O3i	0.93	2.60	3.264 (2)	129
C7—H7A⋯O2i	0.96	2.51	3.283 (2)	138

Symmetry code: (i) .

Figure 2

A chain parallel to [101] formed by the inter­molecular hydrogen bonding (dashed lines) between the N—H group and carbonyl O atom of the DHA moiety. Weak C—H⋯O hydrogen bonds are also shown as dashed lines.

Figure 3

The crystal packing showing the herringbone arrangement of HMNP, viewed along the a axis. C-bound H atoms have been omitted for clarity. Hydrogen bonds are shown as dashed lines.

Hirshfeld surface analysis

The Hirshfeld surface was mapped with d norm to visualize the inter­molecular inter­actions and 2-D fingerprint plots were generated using Crystal Explorer (Wolff et al., 2012 ▸) (Fig. 4 ▸).

Figure 4

(a) Hirshfeld surfaces representation for HMNP mapped with d norm. (b)–(d) Fingerprint plots of HMNP resolved into different inter­molecular inter­actions showing the percentages of contacts contributing to the total Hirshfeld surface.

Spectroscopic and TG analysis

The FT–IR spectrum of the title compound shows a characteristic peak at 1687 cm−1 which has been consigned for ν C=N, whereas the broad signal at 3280 cm−1 (ν O–H) indicates the presence of a phenolic group. The 1H NMR spectrum display a singlet at δ 15.23 ppm, which clearly indicates the dominance of the enol form of the title compound over the keto form. The absorption spectra for HMNP was recorded in C2H5OH, and λmax was observed at 394 nm, which is ascribed to the π→π* or n→π* transition of the C=O or C=N group. To probe the thermal stability of HMNP, thermogravimetric analysis (TGA) was undertaken and it was found that HMNP is stable to 513 K.

Synthesis and crystallization

Materials and methods: p-Nitro­phenyl­hydrazine and de­hydro­acetic acid were of analytical grade and purchased from Spectrochem and Merck (India), respectively, and used as received. However, analytical grade solvents were purified wherever necessary as per as the standard literature method (Perrin et al., 1980 ▸). The FT–IR spectra were recorded with a Perkin–Elmer FTIR–2000 spectrometer. The NMR spectroscopic measurements were carried out with a JEOL AL-400 MHz spectrometer. The thermogravimetric analysis (TGA) measurement was performed on an SDT Q600 (V20.9 Build 20) instrument (Artisan Technology Group, Champaign, IL) under N2 atmosphere with a heating rate of 10 K min−1. The absorbance spectrum was recorded on a JASCO V-530 UV/vis Spectrophotometer.

Synthesis of (E)-4-hy­droxy-6-methyl-3-(1-(2-(4-nitro­phen­yl) hydrazone) eth­yl) 2-H-pyran-2-one (HMNP):

HMNP was synthesized by the reaction of DHA (0.56g, 0.003 mol) with para-nitro­phenyl­hydrazine (0.45g, 0.003 mol) in distilled ethanol (15 mL) under reflux condition at 353 K for 3 h (Fig. 5 ▸). The progress of the reaction was monitored by thin layer chromatography (TLC). After completion of the reaction, the reaction mixture was cooled to room temperature and the yellow crystalline precipitate was filtrated off and washed with cold ethanol and dried [yield: 0.728g (80%)]. Crystals suitable for single crystal X-ray analysis were obtained by the slow evaporation of a THF solution of HMNP for 7–8 d.

Figure 5

Synthetic route for the organic ligand HMNP.

FT–IR (selected peaks): 3280 (O–H), 3088 (N–H), 1687 (C=O), 1646 (C=N) cm−1. Absorption spectrum [λ max, nm, C2H5OH (∊, M −1 cm−1)]: 394 (150), 274 (sh, 525). 1H NMR (CDCl3, 400 MHz): δ (ppm): 15.23 (s, 1H, He), 8.23–8.21 (d, 2H, Ha), 7.34 (1s, 1H, Hc), 6.94–6.93 (d, 2H, Hb), 5.93 (s, 1H, Hf), 2.67 (1s, 3H, Hg), 2.25 (1s, 3H, Hd). 13C NMR (DMSO-d, 100 MHz): δ 176.4 (C8), 167.1 (C12), 163.1 (C10), 150.2 (C7), 139.5 (C4), 125.8 (C1), 111.3 (C2), 103.3 (C3), 96.4 (C9), 79.1 (C5), 78.7 (C11), 78.3 (C6).

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2 ▸. The NH and OH hydrogen atoms were located in a difference-Fourier map and freely refined. The C-bound H atoms were included in calculated positions and treated as riding atoms: C—H = 0.93–0.96 Å, O—H= 0.82 Å with U iso(H) = 1.2U eq(C) and U iso(H) = 1.5U eq(Cmeth­yl). The crystal studied was a non-merohedral twin with the refined ratio of the twin components being 0.3720 (19):0.6280 (19) using twin matrix (0 0) (0 0) (0.265 0 ).

Table 2

Experimental details

Crystal data
Chemical formula	C14H13N3O5
M r	303.27
Crystal system, space group	Monoclinic, P21/n
Temperature (K)	297
a, b, c (Å)	6.9633 (3), 19.5008 (9), 10.2031 (5)
β (°)	95.196 (2)
V (Å3)	1379.78 (11)
Z	4
Radiation type	Mo Kα
μ (mm−1)	0.11
Crystal size (mm)	0.16 × 0.13 × 0.10
Data collection
Diffractometer	Bruker APEXII CCD
Absorption correction	Multi-scan (TWINABS; Sheldrick, 2012 ▸)
No. of measured, independent and observed [I > 2σ(I)] reflections	2696, 2696, 2302
R int	0.028
(sin θ/λ)max (Å−1)	0.617
Refinement
R[F 2 > 2σ(F 2)], wR(F 2), S	0.043, 0.121, 1.08
No. of reflections	2696
No. of parameters	208
No. of restraints	1
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)	0.18, −0.20

Computer programs: APEX2 and SAINT (Bruker, 2010 ▸), SHELXS2013 (Sheldrick 2008 ▸), SHELXL2016 (Sheldrick, 2015 ▸), X-SEED (Barbour 2001 ▸) and publCIF (Westrip 2010 ▸).

Crystal structure: contains datablock(s) I. DOI: 10.1107/S2056989017000639/lh5834sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S2056989017000639/lh5834Isup2.hkl

Click here for additional data file.

Supporting information file. DOI: 10.1107/S2056989017000639/lh5834Isup3.cdx

Click here for additional data file.

Supporting information file. DOI: 10.1107/S2056989017000639/lh5834Isup4.cml

CCDC reference: 1515036

Additional supporting information: crystallographic information; 3D view; checkCIF report

C14H13N3O5	F(000) = 632
Mr = 303.27	Dx = 1.460 Mg m−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 6.9633 (3) Å	Cell parameters from 9944 reflections
b = 19.5008 (9) Å	θ = 2.3–30.3°
c = 10.2031 (5) Å	µ = 0.11 mm−1
β = 95.196 (2)°	T = 297 K
V = 1379.78 (11) Å3	Block, colourless
Z = 4	0.16 × 0.13 × 0.10 mm

Bruker APEXII CCD diffractometer	2302 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.028
Absorption correction: multi-scan (TWINABS; Sheldrick, 2012)	θmax = 26.0°, θmin = 2.3°
	h = −8→8
2696 measured reflections	k = 0→24
2696 independent reflections	l = 0→12

Refinement on F2	1 restraint
Least-squares matrix: full	Hydrogen site location: mixed
R[F2 > 2σ(F2)] = 0.043	H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.121	w = 1/[σ2(Fo2) + (0.0606P)2 + 0.3029P] where P = (Fo2 + 2Fc2)/3
S = 1.08	(Δ/σ)max < 0.001
2696 reflections	Δρmax = 0.18 e Å−3
208 parameters	Δρmin = −0.20 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. Refined as a 2-component twin.

	x	y	z	Uiso*/Ueq
O1	0.3744 (2)	0.45226 (6)	0.80648 (13)	0.0531 (4)
H1	0.344 (4)	0.4379 (12)	0.7235 (19)	0.080*
O2	0.6082 (2)	0.28918 (6)	1.00744 (12)	0.0469 (3)
O3	0.6119 (3)	0.22490 (6)	0.83226 (13)	0.0663 (5)
O4	0.0188 (3)	0.67218 (8)	0.2507 (2)	0.0812 (6)
O5	−0.0004 (3)	0.61297 (9)	0.07175 (19)	0.0865 (6)
N1	0.0349 (3)	0.61838 (9)	0.1917 (2)	0.0611 (5)
N2	0.3120 (2)	0.38498 (7)	0.46572 (14)	0.0398 (4)
H2	0.268 (3)	0.3474 (11)	0.432 (2)	0.048*
N3	0.3581 (2)	0.38475 (6)	0.60024 (13)	0.0347 (3)
C1	0.1015 (3)	0.55793 (9)	0.2667 (2)	0.0451 (5)
C2	0.1693 (3)	0.56440 (9)	0.3967 (2)	0.0444 (4)
H2A	0.167336	0.606928	0.437835	0.053*
C3	0.2406 (3)	0.50781 (8)	0.46645 (17)	0.0391 (4)
H3	0.289862	0.512366	0.553813	0.047*
C4	0.2383 (2)	0.44367 (8)	0.40531 (16)	0.0337 (4)
C5	0.1636 (3)	0.43827 (9)	0.27327 (18)	0.0462 (5)
H5	0.158976	0.395663	0.232158	0.055*
C6	0.0978 (3)	0.49483 (10)	0.20466 (19)	0.0517 (5)
H6	0.050752	0.491001	0.116717	0.062*
C7	0.5379 (3)	0.27794 (9)	0.57620 (17)	0.0454 (5)
H7A	0.454884	0.238623	0.575635	0.068*
H7B	0.664122	0.265763	0.614883	0.068*
H7C	0.546326	0.293406	0.487576	0.068*
C8	0.4574 (2)	0.33419 (8)	0.65505 (16)	0.0332 (4)
C9	0.5723 (3)	0.28148 (8)	0.87201 (16)	0.0410 (4)
C10	0.4942 (2)	0.33851 (8)	0.79792 (15)	0.0329 (4)
C11	0.4516 (3)	0.39848 (8)	0.86652 (17)	0.0389 (4)
C12	0.4968 (3)	0.40211 (10)	1.00539 (19)	0.0491 (5)
H12	0.472308	0.442214	1.050290	0.059*
C13	0.5736 (3)	0.34866 (9)	1.07078 (17)	0.0451 (4)
C14	0.6316 (4)	0.34367 (13)	1.21487 (19)	0.0689 (7)
H14A	0.564868	0.306098	1.251241	0.103*
H14B	0.599050	0.385539	1.257136	0.103*
H14C	0.768155	0.336166	1.228953	0.103*

	U11	U22	U33	U12	U13	U23
O1	0.0792 (10)	0.0393 (7)	0.0400 (7)	0.0220 (7)	0.0012 (7)	0.0015 (6)
O2	0.0651 (8)	0.0416 (7)	0.0322 (6)	0.0067 (6)	−0.0064 (6)	0.0044 (5)
O3	0.1158 (14)	0.0320 (6)	0.0454 (8)	0.0182 (8)	−0.0238 (8)	−0.0018 (6)
O4	0.0772 (12)	0.0448 (9)	0.1196 (16)	0.0129 (8)	−0.0011 (11)	0.0242 (9)
O5	0.0958 (14)	0.0791 (12)	0.0806 (13)	0.0013 (10)	−0.0138 (11)	0.0484 (10)
N1	0.0438 (9)	0.0498 (10)	0.0889 (15)	0.0011 (8)	0.0009 (9)	0.0340 (10)
N2	0.0555 (9)	0.0297 (7)	0.0317 (8)	−0.0015 (7)	−0.0101 (6)	0.0025 (6)
N3	0.0398 (8)	0.0327 (7)	0.0303 (7)	−0.0018 (6)	−0.0039 (6)	0.0047 (5)
C1	0.0382 (9)	0.0397 (9)	0.0563 (12)	−0.0006 (8)	−0.0016 (8)	0.0210 (8)
C2	0.0436 (10)	0.0312 (8)	0.0587 (12)	−0.0023 (8)	0.0059 (9)	0.0048 (8)
C3	0.0427 (9)	0.0347 (8)	0.0389 (10)	−0.0036 (7)	−0.0017 (8)	0.0025 (7)
C4	0.0349 (8)	0.0308 (8)	0.0345 (9)	−0.0030 (6)	−0.0025 (7)	0.0068 (6)
C5	0.0610 (11)	0.0383 (9)	0.0371 (10)	−0.0013 (9)	−0.0068 (9)	0.0042 (7)
C6	0.0611 (12)	0.0516 (11)	0.0396 (10)	−0.0018 (10)	−0.0102 (9)	0.0134 (8)
C7	0.0601 (12)	0.0401 (9)	0.0342 (9)	0.0088 (9)	−0.0052 (8)	−0.0031 (7)
C8	0.0364 (8)	0.0277 (7)	0.0344 (8)	−0.0031 (6)	−0.0026 (7)	0.0014 (6)
C9	0.0547 (11)	0.0331 (8)	0.0329 (9)	0.0011 (8)	−0.0083 (8)	0.0020 (7)
C10	0.0368 (8)	0.0301 (8)	0.0307 (8)	−0.0006 (6)	−0.0024 (7)	0.0023 (6)
C11	0.0458 (10)	0.0337 (8)	0.0371 (9)	0.0051 (7)	0.0028 (7)	0.0024 (7)
C12	0.0670 (13)	0.0450 (10)	0.0354 (9)	0.0098 (9)	0.0053 (9)	−0.0048 (8)
C13	0.0550 (11)	0.0494 (10)	0.0304 (9)	0.0041 (9)	0.0020 (8)	−0.0008 (8)
C14	0.0965 (18)	0.0774 (15)	0.0312 (10)	0.0156 (14)	−0.0026 (11)	−0.0018 (10)

O1—C11	1.305 (2)	C4—C5	1.403 (2)
O1—H1	0.899 (17)	C5—C6	1.363 (2)
O2—C13	1.360 (2)	C5—H5	0.9300
O2—C9	1.390 (2)	C6—H6	0.9300
O3—C9	1.216 (2)	C7—C8	1.499 (2)
O4—N1	1.220 (2)	C7—H7A	0.9600
O5—N1	1.231 (3)	C7—H7B	0.9600
N1—C1	1.458 (2)	C7—H7C	0.9600
N2—C4	1.377 (2)	C8—C10	1.460 (2)
N2—N3	1.3809 (18)	C9—C10	1.424 (2)
N2—H2	0.85 (2)	C10—C11	1.408 (2)
N3—C8	1.301 (2)	C11—C12	1.425 (3)
C1—C2	1.373 (3)	C12—C13	1.324 (3)
C1—C6	1.383 (3)	C12—H12	0.9300
C2—C3	1.381 (2)	C13—C14	1.492 (2)
C2—H2A	0.9300	C14—H14A	0.9600
C3—C4	1.397 (2)	C14—H14B	0.9600
C3—H3	0.9300	C14—H14C	0.9600
C11—O1—H1	104.1 (16)	H7A—C7—H7B	109.5
C13—O2—C9	122.74 (13)	C8—C7—H7C	109.5
O4—N1—O5	123.05 (18)	H7A—C7—H7C	109.5
O4—N1—C1	118.4 (2)	H7B—C7—H7C	109.5
O5—N1—C1	118.5 (2)	N3—C8—C10	115.09 (14)
C4—N2—N3	119.41 (13)	N3—C8—C7	122.27 (14)
C4—N2—H2	115.4 (14)	C10—C8—C7	122.54 (14)
N3—N2—H2	116.0 (14)	O3—C9—O2	113.81 (14)
C8—N3—N2	119.75 (14)	O3—C9—C10	128.22 (15)
C2—C1—C6	120.96 (16)	O2—C9—C10	117.97 (14)
C2—C1—N1	119.85 (18)	C11—C10—C9	118.16 (15)
C6—C1—N1	119.18 (18)	C11—C10—C8	121.23 (14)
C1—C2—C3	120.03 (16)	C9—C10—C8	120.60 (14)
C1—C2—H2A	120.0	O1—C11—C10	122.02 (16)
C3—C2—H2A	120.0	O1—C11—C12	118.12 (15)
C2—C3—C4	119.77 (16)	C10—C11—C12	119.85 (15)
C2—C3—H3	120.1	C13—C12—C11	120.32 (17)
C4—C3—H3	120.1	C13—C12—H12	119.8
N2—C4—C3	123.76 (14)	C11—C12—H12	119.8
N2—C4—C5	117.25 (15)	C12—C13—O2	120.85 (16)
C3—C4—C5	118.95 (15)	C12—C13—C14	127.50 (18)
C6—C5—C4	120.68 (17)	O2—C13—C14	111.65 (16)
C6—C5—H5	119.7	C13—C14—H14A	109.5
C4—C5—H5	119.7	C13—C14—H14B	109.5
C5—C6—C1	119.57 (17)	H14A—C14—H14B	109.5
C5—C6—H6	120.2	C13—C14—H14C	109.5
C1—C6—H6	120.2	H14A—C14—H14C	109.5
C8—C7—H7A	109.5	H14B—C14—H14C	109.5
C8—C7—H7B	109.5
C4—N2—N3—C8	−168.31 (16)	C13—O2—C9—C10	−0.6 (3)
O4—N1—C1—C2	−9.0 (3)	O3—C9—C10—C11	177.1 (2)
O5—N1—C1—C2	170.29 (19)	O2—C9—C10—C11	−2.2 (3)
O4—N1—C1—C6	172.0 (2)	O3—C9—C10—C8	−2.0 (3)
O5—N1—C1—C6	−8.7 (3)	O2—C9—C10—C8	178.60 (16)
C6—C1—C2—C3	1.9 (3)	N3—C8—C10—C11	−9.8 (2)
N1—C1—C2—C3	−177.08 (17)	C7—C8—C10—C11	166.71 (17)
C1—C2—C3—C4	−1.8 (3)	N3—C8—C10—C9	169.40 (16)
N3—N2—C4—C3	12.9 (3)	C7—C8—C10—C9	−14.1 (3)
N3—N2—C4—C5	−169.53 (16)	C9—C10—C11—O1	−177.92 (17)
C2—C3—C4—N2	177.75 (17)	C8—C10—C11—O1	1.3 (3)
C2—C3—C4—C5	0.2 (3)	C9—C10—C11—C12	3.5 (3)
N2—C4—C5—C6	−176.40 (19)	C8—C10—C11—C12	−177.33 (18)
C3—C4—C5—C6	1.3 (3)	O1—C11—C12—C13	179.38 (19)
C4—C5—C6—C1	−1.2 (3)	C10—C11—C12—C13	−2.0 (3)
C2—C1—C6—C5	−0.4 (3)	C11—C12—C13—O2	−0.9 (3)
N1—C1—C6—C5	178.59 (18)	C11—C12—C13—C14	179.3 (2)
N2—N3—C8—C10	−178.73 (15)	C9—O2—C13—C12	2.3 (3)
N2—N3—C8—C7	4.8 (2)	C9—O2—C13—C14	−177.92 (19)
C13—O2—C9—O3	179.91 (19)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···N3	0.90 (2)	1.64 (2)	2.4760 (18)	154 (2)
N2—H2···O3i	0.85 (2)	2.00 (2)	2.8361 (19)	165.2 (19)
C5—H5···O3i	0.93	2.60	3.264 (2)	129
C7—H7A···O2i	0.96	2.51	3.283 (2)	138