Synthesis and Reactions of Lactam Sulfonium Salts with a Sulfonio Bridgehead. II. 1,1a,4,5,6-Pentahydro-6-oxo-2H-thiopyrano(1,6-d)-4,1-benzothiazepinium Perchlorates.
作者:Tadashi KATAOKA、Yoshihide NAKAMURA、Harutoshi MATSUMOTO、Tetsuo IWAMA、Hiroshi SHIMIZU、Osamu MURAOKA、Genzoh TANABE
DOI:10.1248/cpb.45.265
日期:——
Tricyclic benzothiazepinium salts (5) were prepared by [2+ +4] polar cycloaddition of thionium intermediates (4A), generated from corresponding α-chloro sulfides (4) and dienes in the presence of silver perchlorate. X-Ray analysis of 5a revealed that the configuration of the thiazepinone skeleton and the dihydrothiopyran ring is cis-fused.Reactions of benzothiazepinium salts (5) with NaBH4 or NaH afforded 3, 6-epithiobenzazocinone derivatives (9) in high yields by [2, 3]-sigmatropic rearrangement of an ylide intermediate (11). The stereochemistry of epithiobenzazocinone (9a) was determined by the nuclear Overhauser enhancement (NOE) technique and finally by X-ray analysis of the sulfoxide (10) derived from epithiobenzazocinone (9a) by m-chloroperbenzoic acid (MCPBA) oxidation. Alkylation of epithiobenzazocinone (9a) afforded 3-alkyl-3, 6-epithiobenzazocinones (12) with retention of the configuration at C-3. Dihydrothiopyran derivatives (13) were obtained in good yields by SmI2 reduction of benzothiazepinium salts (5).
三环苯噁唑铵盐(5)通过[2+4]极性环加成反应合成,该反应中生成的噻唑中间体(4A),是由相应的α-氯硫化物(4)和二烯在过氯酸银存在下反应得到的。对5a的X射线分析显示,噻唑酮骨架和二氢噻吡啶环的构型是顺式融合的。苯噁唑铵盐(5)与NaBH4或NaH的反应通过[2,3]-σ-转位重排反应产生了高产率的3,6-环噻唑苯唑酮衍生物(9),其中的中间体(11)为亚胺。环噻唑苯唑酮(9a)的立体化学通过核Overhauser增强(NOE)技术确定,最后通过m-氯过苯甲酸(MCPBA)氧化反应获取的硫氧化物(10)的X射线分析确认。对环噻唑苯唑酮(9a)进行烷基化反应,得到了构型在C-3处保持不变的3-烷基-3,6-环噻唑苯唑酮(12)。通过SmI2还原苯噁唑铵盐(5)获得了良产率的二氢噻吡啶衍生物(13)。