INTRAMOLECULAR FUNCTIONALIZATION OF N-CYANAMIDE RADICALS - SYNTHESIS OF 1-4-N-CYANOEPIMINO AND 1,5-N-CYANOEPIMINO COMPOUNDS
INTRAMOLECULAR FUNCTIONALIZATION OF N-CYANAMIDE RADICALS - SYNTHESIS OF 1-4-N-CYANOEPIMINO AND 1,5-N-CYANOEPIMINO COMPOUNDS
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DOI：
10.1039/p19870000937
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发表时间：
1987-04-01
期刊：
影响因子：
--
通讯作者：
BETANCOR, C
中科院分区：
文献类型：
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作者：
CARRAU, R;HERNANDEZ, R;BETANCOR, C
光解3β-甲氧基甲氧基-5 α-胆甾烷-6 β-基氰胺（6）、29-甲氧基非甾烷-3 β-基-氰胺（15）、（22 R，25 R）-5α-呋甾烷-26-基氰胺（23）、8α，12-（12 R/12 S）-环氧非甾烷-15-基氰胺（32）和（33），在碘和四乙酸铅的存在下，导致中性氰酰自由基，其进行分子内氢提取以产生N-氰基表亚氨基化合物。用碘和二乙酰氧基碘苯体系得到较好的结果。起始的氰胺是通过肟（3）和（13）以及酰胺（20）、（28）和（29）分别用氢化铝锂还原，然后用溴化氰或氰酸钠氰化，接着用甲磺酰氯使脲衍生物脱水而制备的。
Photolysis of 3β-methoxymethoxy-5α-cholestan-6β-ylcyanamide (6), 29-methoxyfriedelan-3β-yl-cyanamide (15), (22R,25R)-5α-furostan-26-ylcyanamide (23), 8α,12-(12R/12S)-epoxylabdan-15-ylcyanamides, (32) and (33), in the presence of iodine and lead tetra-acetate leads to neutral cyanimyl radicals which undergo intramolecular hydrogen abstraction to produce N-cyanoepimino compounds. Better results are obtained with the system iodine and diacetoxyiodobenzene. The starting cyanamides have been prepared by reduction of the oximes (3) and (13) and of the amides (20), (28), and (29), respectively, with lithium aluminium hydride followed by cyanation with cyanogen bromide or with sodium cyanate and subsequent dehydration of the urea derivative with methanesulphonyl chloride.