MECHANISM OF TRANSFORMATION OF CYCLOPENIN TO VIRIDICATIN
MECHANISM OF TRANSFORMATION OF CYCLOPENIN TO VIRIDICATIN
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DOI：
10.1021/ja01050a026
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发表时间：
1969-01-01
影响因子：
15
通讯作者：
RAPOPORT, H
中科院分区：
文献类型：
--
作者：
SMITH, HW;RAPOPORT, H
以前被证明在酸性条件下发生的环孢菌素向维拉菌素的转化，现在被发现也发生在热和碱性条件下。异环素和甲基环素也有类似的变化，但后者在碱性条件下不能重排。根据这些观察结果和甲基异氰酸酯是热反应的伴随产物这一事实，提出了涉及三环二烯中间体的脱羧基重排反应机理。开环衍生物不能给出这个反应，证明完整的苯二氮杂二酮环是一个结构要求。环氧化物不是必需的，因为衍生的溴代丙烷可以重排；另外，相应的乙二醇会产生维拉丁，但需要更苛刻的条件。一个二氢类似物，3-甲氧基苄基-4-甲基-3，4-二氢-L，4-苯二氮卓-2，5-二酮，被转化为相应的重排但不脱羧基的氨基甲酰二氢碳酸酯。同样类型的三环二烯中间体是由含羰基的芳香族位置上的苄基碳攻击而得到的，与此相符合。
The transformation of cyclopenin to viridicatin, which had previously been shown to occur in acid, has now been found to takeplace thermally and in alkali as well. Similar changes occur for isocyclopenin and methylcyclopenin, but the latter fails to rearrange in alkali. A mechanism for this decarboxylation-rearrangement, involving a tricyclic diene intermediate, is proposed based on these observations and the factthat methylisocyanate is an accompanying product in the thermal reaction. Ring-opened derivatives fail to give this reaction, demon-strating that the intact benzodiazepinedione ring is a structural requirement. The epoxide is not necessary, since a derived bromohydrin rearranges; also, the corresponding glycol gives viridicatin but requires more drastic con-ditions. A dihydro analog, 3-mesyloxybenzyl-4-methyl-lH-3, 4-dihydro-l, 4-benzodiazepine-2, 5-dione, is trans-formed to thecorresponding rearranged but not decarboxylated carbamoyldihydrocarbostyril. The same type of tricyclic diene intermediate resultingfrom benzylic carbon attack at the carbonyl-bearing aromatic site accom-modates this observation.