Cytenamide–formic acid (1/1)

Andrea Johnston; Alastair J Florence; Gary J Miller; Alan R Kennedy; Colin T Bedford

doi:10.1107/S1600536808019181

. 2008 Jul 5;64(Pt 8):o1379–o1380. doi: 10.1107/S1600536808019181

Cytenamide–formic acid (1/1)

Andrea Johnston ^a, Alastair J Florence ^a,^*, Gary J Miller ^a, Alan R Kennedy ^b, Colin T Bedford ^c

PMCID: PMC2962013 PMID: 21203100

Abstract

In the crystal structure of the title compound [systematic name: 5H-dibenzo[a,d]cycloheptatriene-5-carboxamide–methanoic acid (1/1)], C₁₆H₁₃NO·CH₂O₂, the cytenamide and solvent molecules form a hydrogen-bonded R ₂ ²(8) dimer motif, which is further connected to form a centrosymmetric double-motif arrangement. The asymmetric unit contains two formula units.

Related literature

For details on experimental methods used to obtain this form, see: Davis et al. (1964 ▶); Florence et al. (2003 ▶); Florence, Johnston, Fernandes et al. (2006 ▶). For related literature on cytenamide, see: Florence, Bedford et al. (2008 ▶). For cytenamide analogues, see: Cyr et al. (1987 ▶); Fleischman et al. (2003 ▶); Florence, Johnston, Price et al. (2006 ▶); Florence, Leech et al. (2007 ▶); Bandoli et al. (1992 ▶); Harrison et al. (2006 ▶); Leech et al. (2006 ▶); Florence, Shankland et al. (2008 ▶). For graph-set motifs, see: Etter (1990 ▶).

Experimental

Crystal data

C₁₆H₁₃NO·CH₂O₂
M _r = 281.3
Monoclinic,
a = 11.5351 (13) Å
b = 13.9095 (15) Å
c = 17.6904 (19) Å
β = 95.846 (5)°
V = 2823.6 (5) Å³
Z = 8
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 123 (2) K
0.25 × 0.15 × 0.05 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2002 ▶) T _min = 0.978, T _max = 0.996
55762 measured reflections
12996 independent reflections
9356 reflections with I > 2/s(I)
R _int = 0.025

Refinement

R[F ² > 2σ(F ²)] = 0.047
wR(F ²) = 0.142
S = 1.02
12996 reflections
411 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.58 e Å⁻³
Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2007 ▶); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 (Farrugia, 1997 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: PLATON (Spek, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808019181/rn2044sup1.cif

e-64-o1379-sup1.cif^{(27KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808019181/rn2044Isup2.hkl

e-64-o1379-Isup2.hkl^{(622.6KB, 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
N1—H1N⋯O4	0.884 (15)	2.035 (15)	2.9096 (12)	170.2 (13)
O3—H1O⋯O1	0.927 (18)	1.679 (19)	2.5971 (12)	169.9 (18)
O6—H2O⋯O2	0.91 (2)	1.66 (2)	2.5517 (12)	168.3 (19)
N2—H3N⋯O5	0.895 (15)	2.103 (15)	2.9645 (12)	161.2 (14)
N2—H4N⋯O4	0.843 (16)	2.237 (15)	2.9129 (12)	137.3 (13)
N1—H2N⋯O5	0.866 (16)	2.151 (16)	2.9088 (12)	145.9 (13)

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Acknowledgments

The authors thank the Basic Technology programme of the UK Research Councils for funding this work under the project Control and Prediction of the Organic Solid State (www.cposs.org.uk) and AstraZeneca for funding GJM.

supplementary crystallographic information

Comment

Cytenamide (CYT) is an analogue of carbamazepine (CBZ), a dibenzazepine drug used to control seizures (Cyr et al., 1987). CYT-formic acid solvate was produced during an automated parallel crystallization study (Florence et al., 2006) of CYT as part of a wider investigation that couples automated parallel crystallization with crystal structure prediction methodology to investigate the basic science underlying the solid-state diversity of CBZ (Florence, Johnston, Price et al., 2006; Florence, Leech et al., 2007) and its closely related analogues: CYT (Florence, Bedford et al., 2008), 10,11-dihydrocarbamazepine (DHC) (Bandoli et al., 1992; Harrison et al., 2006; Leech et al., 2006) and cyheptamide (Florence, Shankland et al., 2008). The sample was identified as a new form using multi-sample foil transmission X-ray powder diffraction analysis (Florence et al., 2003). Subsequent manual recrystallization from a saturated formic acid solution by slow evaporation at 278 K yielded a sample suitable for single-crystal X-ray diffraction (Fig. 1).

The molecules crystallize in the space group P2₁/c with two CYT and two solvent molecules in the asymmetric unit. Both CYT molecules form an R₂²(8) (Etter, 1990) dimer motif with adjacent solvent molecules via contacts 1 - 4 (Table 1). In addition, two N—H···O contacts (5 and 6) join adjacent dimers to form a R₄²(8) centrosymmetric double motif (Fig. 2).

This packing arrangement is similar to that in CBZ-formic acid solvate which, in contrast, crystallizes with Z' = 1 in the monoclinic space group P2₁/c (Fig. 2). The main difference being a doubling of the a axis in CYT-formic acid solvate (Z' = 2) (Fleischman et al., 2003)

Experimental

A sample of cytenamide was synthesized according to a modification of the published method (Davis et al., 1964). A single-crystal sample of the title compound was recrystallized from a saturated formic acid solution by isothermal solvent evaporation at 278 ^oK.