The amides prepared from 5,6-dihydro-2-methyl-1,4-oxathiin-3-carbonyl chloride 2 and imidamides 4, carbamimidothioates 4, 2-benzimidazolamine 7, 2-benzothiazolamine 12, and 2-thiazolamine have been studied. The reaction of 2 with imidamides 4 and with carbamimidothioates 4 in the presence of base gave the amides 5, which when heated in toluene underwent the 1,4-oxathiin ring opening and rearrangement to produce 2-substituted-5-[(2-hydroxyethyl)thio]-6-methyl-4(1H)-pyrimidinones 6. Acylation of 2-benzimidazolamine 7 with 2 yielded the amide 10. This, in boiling ethanol, ring opened and rearranged to give the compound 11. The reaction of 2-benzothiazolamine 12 with 2 gave the rearrangement product 14 directly and neither of the possible amides 13 and 15 could be detected. The amide 15 was synthesized by an unambiguous route from 2-aminobenzenethiol and 5,6-dihydro-2-methyl-1,4-oxathiin-3-carbonyl isothiocyanate 3. It would not undergo ring opening and rearrangement when heated. Acylation of 2-thiazolamine with 2 yielded a mixture from which the amide 19 and the rearrangement ester 18 were separated. Structural assignments are based mainly on nmr, uv, and ir spectral evidence.
从5,6-二氢-2-甲基-1,4-噁硫环-3-羰基氯化物2和咪唑酰胺4、氨基甲硫酸酯4、2-苯并咪唑胺7、2-苯并噻唑胺12和2-噻唑胺制备的酰胺已经研究。在碱存在下,2与咪唑酰胺4和氨基甲硫酸酯4发生反应生成酰胺5,当在甲苯中加热时,发生1,4-噁硫环开环重排反应,生成2-取代-5-[(2-羟乙基)硫基]-6-甲基-4(1H)-嘧啶酮6。2-苯并咪唑胺7与2的酰化生成酰胺10。在沸腾的乙醇中,发生环开环重排反应,生成化合物11。2-苯并噻唑胺12与2发生反应,直接生成重排产物14,无法检测到可能的酰胺13和15。酰胺15由2-氨基苯硫醇和5,6-二氢-2-甲基-1,4-噁硫环-3-羰基异硫氰酸酯3经过明确的途径合成。当加热时,不会发生环开环和重排反应。2-噻唑胺与2的酰化产生混合物,从中分离出酰胺19和重排酯18。结构分配主要基于核磁共振、紫外和红外光谱证据。