Ethyl 2-(4-carb-oxy-benzyl-idene)-7-methyl-3-oxo-5-phenyl-2,3-dihydro-5H-thia-zolo[3,2-a]pyrimidine-6-carboxyl-ate-N,N-dimethyl-formamide (1/1).

In the title compound, C(24)H(20)N(2)O(5)S·C(3)H(7)NO, a benzene ring is positioned axially to the pyrimidine ring, which adopts a twist-boat conformation, and is inclined to its mean plane by 85.36 (7)°. In the crystal, inter-molecular C-H⋯O inter-actions result in centrosymmetric head-to-head dimers with an R(2) (2)(14) graph-set motif along the b axis. Pairs of C-H⋯O and O-H⋯O hydrogen bonds form centrosymmetric head-to-head dimers about inversion centres, corresponding to an R(2) (2)(7) graph-set motif along the a axis.