2,4-Diphenyl-4,5-dihydro-3H-pyrido[2,3-b][1,4]diazepine

Hoong-Kun Fun; Chin Sing Yeap; Anita Hazra; Subrata Jana; Shyamaprosad Goswami

doi:10.1107/S1600536809014901

. 2009 Apr 30;65(Pt 5):o1139–o1140. doi: 10.1107/S1600536809014901

2,4-Diphenyl-4,5-dihydro-3H-pyrido[2,3-b][1,4]diazepine

Hoong-Kun Fun ^a,^*,^‡, Chin Sing Yeap ^a,^§, Anita Hazra ^b, Subrata Jana ^b, Shyamaprosad Goswami ^b

PMCID: PMC2977810 PMID: 21583947

Abstract

The asymmetric unit of the title compound, C₂₀H₁₇N₃, contains two crystallographically independent molecules (A and B). In molecule A, the two benzene rings form dihedral angles of 74.12 (7) and 7.83 (7)° with the pyridine ring, while in molecule B these angles are 77.48 (7) and 21.50 (7)°. The seven-membered heterocyclic ring adopts a boat conformation in both molecules. In the crystal structure, each of the independent molecules forms a centrosymmetric R ₂ ²(8) dimer linked by paired N—H⋯N hydrogen bonds. The crystal structure is further stabilized by intermolecular C—H⋯N hydrogen bonds and C—H⋯π interactions.

Related literature

For bond-length data, see: Allen et al. (1987 ▶). For general background and the biological applications of pyridodiazepine compounds, see: Landquist et al. (1984 ▶); Smalley et al. (1979 ▶); Goswami et al. (2009 ▶). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C₂₀H₁₇N₃
M _r = 299.37
Triclinic,
a = 5.9969 (3) Å
b = 15.3186 (6) Å
c = 17.0676 (7) Å
α = 82.588 (3)°
β = 85.266 (2)°
γ = 88.670 (2)°
V = 1549.37 (12) Å³
Z = 4
Mo Kα radiation
μ = 0.08 mm⁻¹
T = 100 K
0.50 × 0.33 × 0.05 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.948, T _max = 0.996
35167 measured reflections
9044 independent reflections
5978 reflections with I > 2σ(I)
R _int = 0.053

Refinement

R[F ² > 2σ(F ²)] = 0.054
wR(F ²) = 0.133
S = 1.08
9044 reflections
423 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.25 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809014901/ci2786sup1.cif

e-65-o1139-sup1.cif^{(29.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809014901/ci2786Isup2.hkl

e-65-o1139-Isup2.hkl^{(442.3KB, hkl)}

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3A—H3NA⋯N2Aⁱ	0.90 (2)	2.10 (2)	2.9572 (17)	157 (1)
N3B—H3NB⋯N2Bⁱⁱ	0.91 (2)	2.29 (2)	3.0980 (17)	148 (1)
C6A—H6AA⋯N1Aⁱⁱⁱ	0.98	2.60	3.4316 (17)	143
C2B—H2BA⋯Cg1	0.93	2.79	3.6350 (14)	151
C20B—H20B⋯Cg2	0.93	2.79	3.4468 (15)	129

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) . Cg1 and Cg2 are the centroids of the N2A/C1A–C5A and C7B–C12B rings, respectively.

Acknowledgments

AH, SJ and SG thank the DST [SR/S1/OC-13/2005], Government of India, for financial support. AH thanks the CSIR, Government of India, for a research fellowship. HKF thank Universiti Sains Malaysia for the Research University Golden Goose grant No. 1001/PFIZIK/811012. CSY thanks the Malaysian Government and Universiti Sains Malaysia for the award of the post of research officer under the Science Fund (grant No. 305/PFIZIK/613312).

supplementary crystallographic information

Comment

Pyridodiazepines are bicyclic heterocyclic compounds comprising of pyridine nucleus fused to a seven-membered ring containing two nitrogen atoms (Landquist et al., 1984). These compounds have important role in biological and therapeutic applications (Smalley et al., 1979). 2,4-Diphenyl-4,5-dihydro-3H-pyrido[2,3-b][1,4]diazepine was synthesized by our newly developed microwave technique (Goswami et al., 2009). We report here the crystal structure of this compound.

The asymmetric unit of title compound (Fig 1), consists of two crystallographically independent molecules, A and B. In the molecule A, the C7A-C12A and C15A-C20A rings form dihedral angles of 74.12 (7)° and 7.83 (7)°, respectively, with the N2A/C1A-C5A ring, while in B these angles are 77.48 (7)° and 21.50 (7)°. The bond lengths (Allen et al., 1987) and angles are within normal ranges. The seven-membered heterocyclic ring adopts a boat conformation.

In the crystal structure, A/A and B/B pairs of inversion related molecules are linked by N—H···N hydrogen bonds forming R₂²(8) dimers (Fig. 2). The crystal structure is further stabilized by intermolecular C—H···N hydrogen bonds and C—H···π interactions (Table 1).

Experimental

A mixture of pyridine-2,3-diamine (109 mg, 1.0 mmol) and the chalcone benzylideneacetophenone (208 mg, 1.0 mmol) was thoroughly grinded and taken in an open mouth conical flask and then irradiated at 400 W for 35 min in a microwave oven. The residue was dissolved in water and then extracted with CHCl₃. The crude product was purified through column chromatography to afford a pure yellow-colored 2,4-diphenyl-4,5-dihydro-3H-pyrido[2,3-b][1,4]diazepine. Single crystals were grown by slow evaporation of a chloroform solution (m.p. 126-128 °C).