STRUCTURE OF 5 ( 4' - NN - DIMETHYL) BENZYLIDENE - 2 PHENOLOXAZOLE - 4 - ONE, C₁₈H₁₆N₂O₂ S. Karmakar, A. N. Talukdar, Department of Physics, Gauhati University, Guwahati - 781014, India.

'The benzylidene ring ( A ), the oxazolone ring system (B) and the attached phenyl ring (C) of the title compound ( Fig 1 ) are almost planar having interplanar angles between A and B and that between B and C 4.3deg. and 2.5deg. respectively. The compound crystallises in monoclinic space group P2₁/c. Intensity data were collected on an Enraf- Nonius CAD - 4 diffractometer using CuK_[[alpha]] radiation. 'I'he structure was solved direct methods ( SHELXS 86 ) and refined by full - matrix least squares methods (SHELX 90 ) . The final R value is 0.068 for 1866 reflections. The N,N - dimethyl group is nearly coplanar with the benzylidene ring plane. There is no any hydrogen bonds and the structure is stabilised by van der Walls interaction in their crystalline space.

The crystal data are: a = 12.177 ( 4 ), b = 3.966 ( 1 ),

c = 30.944 ( 8 )Adeg.; [[beta]]= 101.17 ( 1) deg., z = 4, D_x =1.319 Mg m^-3,

D_m = 1.332 Mg m^-3.