X-ray mapping in heterocyclic design: IV. Crystal structure determination of 3-(p-nitrobenzoyl)-2-oxooxazolo[3,2-a]pyridine from powder diffraction data

The structure of 3-(p-nitrobenzoyl)-2-oxooxazolo[3,2-a]pyridine is determin ed by the powder diffraction technique. The crystals are monoclinic, a = 13 .642(2) Angstrom, b = 22.278(3) Angstrom, c = 3.917(1) Angstrom, beta = 90. 63(2)degrees, Z = 4, and space group P2(1)/n. The structure is solved by a modified Monte Carlo method and refined by the Reitveld method. The six-mem bered heterocycle is characterized by the alternation of partially single a nd partially double bonds. The system of two conjugated heterocycles is pla nar and forms a dihedral angle of 46.1(1)degrees with the plane of the phen yl ring. The nitro group is virtually coplanar with the phenyl fragment. An extensive system of intramolecular and intermolecular contacts involving h ydrogen, oxygen, and nitrogen atoms is observed in the crystal. (C) 2001 MA IK "Nauka/lnterperiodica".