Study on the Conversion of 1,5,3,7-Dichalcogenadiazocines to Cyclic Polychalcogenides

目前的兴趣已集中在环硫族缩醛断裂产生的含硫族原子的反应物种。然而，很少有研究的环状polyaminopolychalcogenacetals的氧化已经实现了尽管期望通过氧化环收缩得到各种含硫族元素的杂环。特别是，构象灵活的八元氨基硫属缩醛的氧化将引起自发的跨环Ch-Ch相互作用，生成1，5，3，7-二硫属二氮杂双环[3.3.0]辛烷型二硫属双阳离子，通过亲核试剂对双阳离子的亚甲基碳的攻击，这些双阳离子将进一步断裂，得到新型环状二硫属化合物。我们将描述一种新的将3，7-二取代的2 H，6 H-四氢-1，5，3，7-二硫杂环庚二氮杂环辛烯用各种氧化剂处理成1，2，4-二硫杂环庚二氮杂环辛烯的方法。用溴处理3，7-二取代的2 H，6 H-四氢-1，5，3，7-二硫杂环庚二氮杂环辛烯得到6 H-二氢-1，2，3，4，5，7-五硫杂环辛烯的产率中等，在该反应体系中加入元素硫导致五硫杂环辛烯产率的增加。与氯化硫反应得到了较好的产率，而二硒二氮杂环辛烯和二碲二氮杂环辛烯与各种氧化剂反应得到了相应的3 H-二氢-1，2，4-硫属唑烷，产率较高。2 H，6 H-四氢-1，5，3，7-二硫杂环庚二氮杂环辛二烯经不同氧化剂选择性缩环得到1，2，3，4，5，7-五硫杂环庚二烯和1，2，3，4，5，7-五硫杂环庚二烯。2，4-二硒或二碲唑烷。

Current interest has been concentrated on the chalcogen atom-containing reactive species generated by the fragmentation of cyclic chalcogenoacetals. However, few studies on the oxidation of cyclic polyaminopolychalcogenoacetals have been achieved in spite of the expectation to give various chalcogen-containing heterocycles through the oxidative ring contraction. Especially, it was expected that oxidation of conformationally flexible eight membered aminochalcogenoacetals would cause spontaneous transannular Ch-Ch interaction to give 1,5,3,7-dichalcogenadiazabicyclo[3.3.0]octane-type dichalcogena dications which would undergo further fragmentation to give novel cyclic dichalcogenidesby the attack of nucleophiles toward the methylene carbons of the dications, In this paper, we would like to describe a novelring contraction of 3,7-Disubstituted 2 H,6H-tetrahydro-1,5,3,7-dichalcogenadiazocines to 1,2,4-dichalcogenazolidines by treating with various oxidizing agents.Treatment of 3,7-disubstituted 2 H,6H-tetrahydro-1,5,3,7-dithiadiazocines with bromine afforded 6H-dihydro-1,2,3,4,5,7-pentathiazocines in moderate yield and the addition of elemental sulfur in this reaction systems resulted in an increase of the yields of pentathiazocines. Reaction with sulfur chloride resulted in a good yield.On the other hand, treatment of diselenadiazocines and ditelluradiazocines with various oxidizing agents afforded the corresponding 3H-dihydro-1,2,4-chalcogenazolidines in good yields. The intermediates of the reactions were supposed to be diselena or ditellura dications possessing 1,5,3,7-dichalcogenadiazabicyclo[3.3.0]octane skeleton generatedtransiently by the transannular interaction of two chalcogen atoms.In conclusion, 2H,6H-tetrahydro-1,5,3,7-dichalcogenadiazocines subjected to selective ring contraction by treating with various oxidizing agents gave 1,2,3,4,5,7-pentathiazocines and 1,2,4-diselena- or ditellurazolidines, respectively.