A convenient and efficient three-component reaction to a one-pot synthesis of thiophene derivatives from activated acetylenic compounds and ethyl 2chloroacetoacetate in the presence of tetramethyl thiourea in water lead to the formation of thiophenes in good yields.

The title compound PBPEA, C(10)H(7)Br(5)O(2), has its ethyl acetate portion nearly orthogonal to the benzene ring, with a C-C-C-C torsion angle of 88.3 (5)°. The packing involves an inter-molecular contact with a Br⋯Br distance of 3.491 (1) Å, having C-Br⋯Br angles of 173.4 (2) and 106.0 (2)°. The crystal studied was an inversion twin.

The title compound, C(12)H(14)N(2)O(3)S, adopts a cis-trans geometry of the thio-urea group and is stabilized by intra-molecular hydrogen bonds between the carbonyl O atoms and the H atom of the thio-amide group and by a C-H⋯S interaction. Mol-ecules are linked by two inter-molecular hydrogen bonds (C-H⋯O and N-H⋯O), forming a one-dimensional chain parallel to the c axis.

In the title mol-ecule, C(10)H(11)NO(5), the methyl C atom deviates by 0.830 (6) Å from the mean plane of the remaining non-H atoms. In the crystal, weak C-H⋯O hydrogen bonds link the mol-ecules into layers parallel to the bc plane.