Synthesis and mass spectral fragmentation patterns of some thiazole and imidazolidine derivatives

3-[(Thiophen-2-ylmethylene)-amino]-4-oxo-imidazolidin-2-thione 4 and 5-aryl-2-[(thiophen-2-ylmethylene)-hydrazino]-thiazole 5 have been prepared via cyclization of l-(thiophen-2-ylmethylene)-thiosemicarbazone 3 with ethyl chloroacetate and ω-bromomethyl aryl ketones in presence of fused sodium acetate. Reaction of compounds 4 and 5 with hydrazine hydrate and acetic anhydride gives l,2-bis-(thiophen-2-ylmethylene)-hydrazone 7 and N-acetyl derivatives 6 and 10. Treatment of 4 with benzyl chloride, choloracetyl chloride and 4-chlorobenzaldehyde yields the corresponding N-benzyl derivative 8, imidazolo [5, 1-c]-oxazine 9 and 3-[(thiophen-2-ylmethylene)-amino]-4-oxo-5-(4-chlorobenzylidene)-imidazolidin-2-thione 11, respectively. The mass spectral fragmentation patterns of some prepared compounds have been investigated in order to elucidate the structure of the synthesized compounds.