Comment

Pyrrolo[2,3]pyrimidines are an important class of compounds that are structurally and chemically related to nucleosides and some antibiotics (Ohgi et al., 1979; Tolmann et al., 1968). The well known biological activity of these compounds has led to intensive investigation of their use as antitumor, anti-allergic, antiviral and anti-inflammatory agents (Hutzenlaub et al., 1972; Smith et al., 1972).

In the light of this, we have synthesized and characterized the title compound, (2), and have determined its structure by X-ray analysis.

Fig. 1 shows the molecular structure of (2), with the atomic numbering scheme. The six-membered non-aromatic ring (C2/C1/N1/C5/N2/C6) has a total puckering amplitude of 0.532 (3) Å (Cremer & Pople, 1975) and a boat conformation [ = 179.5 (4)° and = 105.0 (5)°]. The five-membered aromatic ring (C1-C4/N3) and the five benzene rings (C7-C12, C13-C18, C19-C24, C25-C30 and C31-C36) are each essentially planar, with r.m.s. deviations of 0.0296 (13), 0.0104 (14), 0.0069 (15), 0.0067 (15), 0.046 (16) and 0.126 (15) Å, respectively. The bond lengths and angles are in agreement with reported literature values (Allen et al., 1987).

The structure is stabilized by intra- and intermolecular C-HO hydrogen bonds (Table 1). In the crystal structure, the C-HO intermolecular hydrogen bonds link the molecules into dimers which are stacked along the b axis (Fig. 2).

Figure 1 The molecular structure of (2), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms have been omitted.

Figure 2 Packing diagram of (2); C-HO hydrogen bonds are shown as dashed lines.

Experimental

Compound (1) was prepared from the cyclocondensation reaction that occurs between p,p'-dimethoxydibenzoylketene and oxalyl chloride (Hökelek et al., 2002). Compound (2) was obtained from (1) (1.0 g, 2.96 mmol) by reaction with an excess of p-tolyl isocyanate in a 25 ml round-bottomed flask equipped with a calcium chloride tube. The mixture was heated at 338 K for 24 h. After cooling to room temperature, the residue was triturated with anhydrous diethyl ether, and the crude product was recrystallized from ethanol (yield 1.26 g, 66%; m.p. 475 K). IR (KBr, cm^-1): 1727 (C3-O1), 1709 (C4-O2), 1684 (C5-O3); ¹H NMR (CDCl₃, p.p.m..): 7.64-6.04 (m, 20H, Ar-H), 3.88, 3.77 (s, 6H, CH₃O), 2.25, 2.18, 2.15 (s, 9H, Ar-CH₃); ¹³C NMR (CDCl₃, p.p.m..): 178.51 (C3-O1), 165.58 (C4-O2), 164.47 (C5-O3), 162.35-115.52 (C=C, arom. and aliph.), 81.36 (N1-C1-N2), 57.50 (O4-C38), 57.28 (O5-C37), 23.00, 22.94, 22.92 (Ar-CH₃). Analysis calculated for C₄₁H₃₅N₃O₅: C 75.80, H 5.39, N 6.47%; found: C 76.02, H 5.69, N 6.22%.

Crystal data

C41H35N3O5 Mr = 649.72 Triclinic, a = 10.1797 (12) Å b = 12.5347 (14) Å c = 13.6855 (16) Å = 107.999 (2)° = 99.985 (2)° = 90.504 (2)° V = 1632.0 (3) Å3 Z = 2 Dx = 1.322 Mg m-3 Mo K radiation Cell parameters from 3062 reflections = 4.7-50.5° = 0.09 mm-1 T = 150 (2) K Block, yellow 0.38 × 0.21 × 0.10 mm

Data collection

Bruker SMART 1000 CCD area-detector diffractometer scans Absorption correction: multi-scan(SADABS; Bruker, 1997)Tmin = 0.968, Tmax = 0.991 18940 measured reflections 7331 independent reflections 4028 reflections with I > 2(I) Rint = 0.054 max = 27.6° h = -13 13 k = -16 16 l = -17 17

Refinement

Refinement on F2 R[F2 > 2(F2)] = 0.050 wR(F2) = 0.129 S = 0.98 7331 reflections 445 parameters H-atom parameters constrained w = 1/[2(Fo2) + (0.054P)2 + 0.1342P] where P = (Fo2 + 2Fc2)/3 (/)max < 0.001 max = 0.26 e Å-3 min = -0.25 e Å-3

Table 1 Hydrogen-bond geometry (Å, °) D-HA D-H HA DA D-HA C9-H9AO1i 0.95 2.55 3.409 (3) 150 C11-H11AO2ii 0.95 2.53 3.158 (3) 123 C18-H18AO3 0.95 2.58 2.927 (3) 102 C30-H30AO2 0.95 2.55 2.928 (3) 104 C32-H32AN1 0.95 2.51 2.858 (3) 102 C39-H39CO5iii 0.98 2.48 3.422 (3) 160 C40-H40CO4iv 0.98 2.54 3.341 (3) 139 Symmetry codes: (i) -x, -y+1, -z; (ii) -x+1, -y+1, -z; (iii) x-1, y, z; (iv) x+1, y, z+1.

H atoms were positioned geometrically [0.95 (CH) and 0.98 Å (CH₃)] and constrained to ride on their parent atoms, with U_iso(H) values of 1.2 (1.5 for methyl) times U_eq.

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SHELXTL (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.