93074-68-1Relevant academic research and scientific papers
Condensation of (2-Bromo-1-phenylethylidene)malononitrile with Substituted Thioureas: An Unusual Ring Size Effect
Svetlik, Jan,Turecek, Frantisek,Goljer, Igor
, p. 4740 - 4744 (2007/10/02)
Condensations of the title electrophile with ambient S,N-nucleophiles, e.g., thiourea, N,N'-diphenylthiourea, and thiosemicarbazide, proceed via initial S-alkylation followed by closure of the thiazole ring.In contrast to this, cyclic thioureas with the five-, six- and seven-membered rings afford distinct condensation products depending on the size of the ring. 2-Imidazolinethione gave 7-cyano-2,3-dihydro-5-mercapto-6-phenyl-1H-pyrrolo-imidazole in low yield. 3,4,5,6-Tetrahydro-2(1H)-pyrimidinethione afforded malonitrile in high yield, while 1,3,4,5,6,7-hexahydro-2H-1,3-diazepine-2-thione gave 7-amino-8-cyano-9-phenyl-2,3,4,5-tetrahydropyridodiazepine in moderate yield.A common feature of these cyclizations is the primary S-nucleophilic attack, which was confirmed by isolation and characterization of the corresponding intermediates.The effects of ring size are discussed.
