Synthesis and mass spectra of some new heterocyclic compounds containing thiophene moiety

Reaction of ethyl beta-[thiophen-2-yl]-alpha-cyanoacrylate I with guanidine hydrochloride and thiosemicarbazide gave the corresponding 2-aminopyrimidine derivative 2 and thiophen-2-yl carboxaldehvde thiosemicarbazone 4. Treatment of 4 with acetic anhydride, benzyl chloride, hydrazine hydrate and bromine solution afforded the corresponding N-diacetyl and N-benzylthiosemicarbazones 5, 6, hydrazone derivative [7] and 1, 2, 4-triazole derivative 8. Acylation of 2 and 8 with acetic anhydride yielded the corresponding N-acetyl derivatives 3 and 9. The mass spectral fragmentation patterns of the some compounds are described