Preparation of New Nitrogen-Bridged Heterocycles. 46. Selective Formation of 4(1H)-8,8a-Dihydro-1,4-thiazino[3,4,5-cd]indolizinone and (E)-3-(1,3-Oxathiol-2-ylidene)-2(3H)-indolizinone Derivatives.
作者:Akikazu KAKEHI、Suketaka ITO、Hiroyuki SUGA、Toshiyuki KOBAYASHI、Susumu HATANAKA
DOI:10.1248/cpb.46.1866
日期:——
The reactions of (Z)-3-[mercapto(methylthio)methylene]-2(3H)-indolizinones with bromoacetonitrile and bromoacetates in the presence of a base gave the corresponding 4(1H)-8, 8a-dihydro-1, 4-thiazino[3, 4, 5-cd]indolizinone derivatives, but similar treatment of the same compounds with some phenacyl bromides provided a quite different type of product, (E)-3-(5-aryl-1, 3-oxathiol-2-ylidene)-2(3H)-indolizinones, in 12-74% yield with the evolution of methanethiol. Interestingly, the reactions of (Z)-3-[mercapto(phenacylthio)methylene]-2(3H)-indolizinones and iodomethane in the presence of a base did not afford the expected (Z)-3-(5-aryl-1, 3-oxathiol-2-ylidene)-2(3H)-indolizinones, but gave only the same (E)-isomers in 22-53% yields. The stereochemistry about the C3-C2' double bond in these 3-(5-aryl-1, 3-oxathiol-2-ylidene)-2(3H)-indolizinones was determined to be (E) by X-ray analysis.
(Z)-3-[巯基(甲硫基)亚甲基]-2(3H)-吲嗪酮与溴乙腈和溴乙酸酯在碱存在下的反应得到了相应的 4(1H)-8,8a-二氢-1,4-噻嗪并[3,4,5-cd]吲嗪酮衍生物、但用一些苯酰基溴化物对相同化合物进行类似处理,可得到一种完全不同类型的产物--(E)-3-(5-芳基-1, 3-氧硫杂环戊烯-2-亚基)-2(3H)-吲嗪酮,产率为 12-74%,并伴有甲硫醇的演化。有趣的是,(Z)-3-[巯基(苯硫基)亚甲基]-2(3H)-吲嗪酮与碘甲烷在碱存在下的反应并没有得到预期的(Z)-3-(5-芳基-1, 3-氧硫杂环戊-2-亚基)-2(3H)-吲嗪酮,而只得到了相同的(E)-异构体,产率为 22-53%。通过 X 射线分析,确定这些 3-(5-芳基-1, 3-氧硫杂环戊-2-亚基)-2(3H)-吲嗪酮中 C3-C2' 双键的立体化学结构为 (E)。