Crystal structure of 4-(4-bromophenyl)-1,7,7-trimethyl-1,2,3,4,5,6,7,8- octahydroquinazoline-2,5-dione.

hydroquinazoline-2,5-dione was obtained from Biginelli-type cyclocondensation1 of 5,5-dimethylcyclohexane-1,3-dione with urea and 4-bromobenzaldehyde: yield 1.16 g (62.19%), m.p. 174 – 175 ̊C. A summary of the key crystallographic information is given in Table 1. The atomic coordinates and equivalent isotropic displacement parameters with estimated standard deviations for atoms except H are listed in Table 2, and selected bond lengths and bond angles in Table 3. A perspective view of the title molecule showing the atomnumbering scheme is presented in Fig. 2. The phenyl ring at C4 is nearly perpendicular to the quinazoline ring system, with the dihedral angle of 84.4(1) ̊. The observed bond lengths of both C–O in these structures are normal. The differences between the lenghts of C2–N1 and C2– N3 are 0.065 Å, similar to the value of 0.065 Å found in 1,7,7trimethyl-4-(4-methylphenyl)-1,2,3,4,5,6,7,8-octahydro1023 ANALYTICAL SCIENCES AUGUST 2001, VOL. 17 2001 © The Japan Society for Analytical Chemistry