Ethyl 2-(4-carb­oxy­benzyl­idene)-7-methyl-3-oxo-5-phenyl-2,3-dihydro-5H-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate–N,N-dimethyl­formamide (1/1)

In the title compound, C₂₄H₂₀N₂O₅S·C₃H₇NO, 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, inter­molecular C—H...O inter­actions result in centrosymmetric head-to-head dimers with an R₂²(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 R₂²(7) graph-set motif along the a axis.

Ethyl 7-methyl-3-oxo-5-phenyl-2-(2,4,6-trimeth­oxy­benzyl­idene)-2,3-dihydro-5H-thia­zolo[3,2-a]pyrimidine-6-carboxyl­ate

In the title compound, C₂₆H₂₆N₂O₆S, the benzene ring is positioned axially to the thia­zolopyrimidine ring and bis­ects it with a dihedral angle of 80.94 (7)°. The pyrimidine ring adopts a flattened boat conformation. In the crystal, pairs of bifurcated C—H...O hydrogen bonds link the mol­ecules into chains along the c axis.