“…The angle between the least squares planes formed by the N1± ±C2± ±N3 and C4± ±C5± ±C6 atoms of the pyrimidine ring is 30.1(3) . This angle appers sensitive to the type of the substituents present in the related ring, since the corresponding angles in 1 H-pyrimidine-2-thione (Akc Ëamur, Altural, Sarõpõnar et al, 1988), 5-benzoyl-1-[4-(dimethylamino)phenyl-methyleneamino]-4-phenyl-1 H-pyrimidine-2-one (Akkurt and Hiller, 1993), 1-amino-5-benzoyl-4-phenyl-1 H-pyrimidine-2-thione (Akkurt, Gu Èldeste, Soylu, Altural, Sarõpõnar, 1992) and in 1-allyl-5-benzoyl-4-phenylpyrimidine-2-one (Úztu Èrk, Akkurt, Ho Èkelek, Yõldõrõm, 1997) are 5.3, 7.5, 0.7 and 9.0(7) respectively. The conformation of the dihydropyrimidine ring can be described as a distorted boat with the C(4) atom displaced most from the plane of the ring; the puckering coordinates (Cremer and Pople, 1975) are: S 0X37(3), j À175X3(5) , q 76X94(5) , and in 2-methyl-5,6,7-triphenyl-6,7-dihydro-pyrazolo[2,3-a]pyrimidine (Lindeman, Struckhov, Shishkin, Desenko, Lipson, Orlov, 1993), these parameters are: S 0X56, j 27X4 , q 45X4 .…”