THE RECTIONS OF SOME BROMO-DERIVATIVES OF COMPOUNDS HAVING REACTIVE METHYLENE GROUPS WITH THIOUREAS, AND OF SOME RESULTANT THIOURONIUM SALTS WITH BASE

Article abstract of DOI:10.1016/0040-4020(80)80140-2

Whereas α-bromocarbonyl compounds react with thiourea to give thiazole derivatives, bromomalononitrile and bromobis(phenylsulphonyl)methane underwent protodebromination.With N,N,N',N'-tetramethylthiourea many of the bromo compounds gave thiouronium salts but protodebromination sometimes supervened.N,N'-Disubstituted thioureas provided examples of salt formation, protodebromination and cyclisation reactions.The only thiouronium salt to provide an ylide on treatment with base was the S--N,N,N',N'-tetramethylthiouronium bromide.N,N'-Disubstituted salts gave isothioureas rather than ylides.Thiouronium dicyano methylide underwent cyclisation rather than a Wittig reaction when heated with p-nitrobenzaldehyde, and the aldehyde condensed with the resultant 2-aminothiazole.