N-Bis(methylthio)methylene Derivatives. VII. Syntheses and Reactions of Synthetic Equivalents of New 1,3-Dipolar Reagents Using N-Bis(methylthio)methylene Derivatives.
作者:Yoshinori TOMINAGA、Koichiro OGATA、Hiroshi UEDA、Shinya KOHRA、Akira HOSOMI
DOI:10.1248/cpb.43.1425
日期:——
N-Cyano- or N-(p-toluenesulfonyl)-N'-(trimethylsilylmethyl)-S-methylisothioureas (3, 4), readily prepared by reactions of S, S'-dimethyl N-cyano- (1a)b and S, S'-dimethyl N-(p-toluenesulfonyl)- (1b) carbonimidodithioates with trimethylsilylmethylamine (2a), followed by N-alkylation, have been found to provide synthetic equivalents of iminoazomethine ylide. Treatment of these compounds with cesium fluoride in the presence of reactive hetero-dipolarophiles such as carbonyl compounds afforded 1, 3-dipolar cycloadducts, 4, 5-dihydro-2-iminooxazoles and 4, 5-dihydro-2-iminothiazoles, via the 1, 3-elimination of (methylthio)trimethylsilane.S-Methyl-S'-trimethylsilylmethyl N-cyano- (5a) and N-(p-toluene-sulfonyl)- (5b) carbonimidodithioates, also readily prepared from the corresponding 1a and 1b with (mercaptomethyl)trimethylsilane (2b), were used as new reagents for introducing a thioformaldehyde unit at a carbonyl carbon. Reactions of these compounds with aldehydes in the presence of cesium fluoride afforded thiiranes via the 1, 3-dipolar cycloaddition of iminothiocarbonyl ylide to the C=O double bond. Reactions of 5 with dimethyl fumarate and maleate in the presence of cesium fluoride in acetonitrile gave 1, 3-dipolar cycloadducts, dimethyl 2-(N-(p-toluenesulfonyl)imino)tetrahydrothiophene-3, 4-dicarboxylates.
N-
氰基或N-(对
甲苯磺酰)-N'-(三
甲基硅甲基)-S-
甲基异
硫脲(3, 4),通过S,S'-二
甲基N-
氰基(1a)和S,S'-二
甲基N-(对
甲苯磺酰)(1b)双
碳酰亚胺与三
甲基硅甲基胺(2a)反应,随后进行N-烷基化,可以方便地制备,并被发现提供了
亚胺偶
氮烷亚基的合成等效物。这些化合物在
氟化铯存在下,与活性杂双极体如羰基化合物处理,通过(甲
硫基)三
甲基硅烷的1,3-消除,得到了1,3-偶极环加成产物,4,5-二
氢-2-
亚胺恶唑和4,5-二
氢-2-
亚胺噻唑。S-
甲基-S'-(三
甲基硅甲基)N-
氰基(5a)和N-(对
甲苯磺酰)(5b)
碳酰亚胺,也可以通过相应的1a和1b与(巯
甲基)三
甲基硅烷(2b)方便地制备,被用作新的试剂,在羰基
碳上引入
硫甲醛单元。这些化合物在
氟化铯存在下与醛反应,通过
亚胺碳酰亚胺偶极体与C=O双键的1,3-偶极环加成,得到了
硫杂
环丙烷。5在
氟化铯存在下与
富马酸二甲酯和
马来酸二甲酯反应,得到了1,3-偶极环加成产物,二
甲基2-(N-(对
甲苯磺酰)
亚胺)四
氢硫杂
环戊烯-3,4-二
甲酸酯。