Ethyl 6-ethoxy-carbonyl-methyl-4-(2-hydroxy-phen-yl)-2-oxo-1,2,3,4-tetra-hydro-pyrimidine-5-carboxyl-ate.

The title compound, C(17)H(20)N(2)O(6), belongs to the monastrol-type of anti-cancer agents and was selected for crystal structure determination in order to confirm its mol-ecular structure and explore some aspects of its structure-activity relationships. The central tetra-hydro-pyrimidine ring has a flat-envelope conformation. The 4-hydroxy-phenyl group occupies a pseudo-axial position and is inclined at an angle of 87.7 (2)° to the mean plane of the heterocyclic ring. Of the two ethyl ester groups, one (in the 5-position) is in a coplanar and the other (in the 6-position) is in a perpendicular orientation with respect to the heterocyclic plane. There is a three-dimensional hydrogen-bonding network in which all hydrogen-bond donors and acceptors are involved.