Isothiazoles. Part IV. Cycloaddition reactions of diaryl-oxazolones and münchnones to 3-diethylamino-4-(4-methoxyphenyl)-isothiazole 1,1-dioxide: a new synthesis of triarylpyrroles
作者:Paola Baggi、Francesca Clerici、Maria L Gelmi、Sabrina Mottadelli
DOI:10.1016/0040-4020(94)01110-l
日期:1995.2
with oxazolones 2 and münchnones 7 affording with satisfactory yield 3-diethylamino-4,6-diaryl-3a,4-dihydro-3a-(4-methoxyphenyl)-6aH-pyrrolo[3,4-d]isothiazole 1,1-dioxides 4 and 3-diethylamino-4,6-diaryl-5-alkyl-3a-(4-methoxyphenyl)-pyrrolo[3,4-d]isothiazole 1,1-dioxides 8, respectively. The behaviour of the cycloadducts towards elevated temperatures and/or basic conditions was investigated. Under these
3-二乙氨基-4-(4-甲氧基苯基)-异噻唑1,1-二氧化物(3)易于与恶唑酮2和苯甲酸酯7反应,得到令人满意的收率3-二乙氨基-4,6-二芳基-3a,4-二氢-3a -(4-甲氧基苯基)-6aH-吡咯并[3,4-d]异噻唑1,1-二氧化物4和3-二乙氨基-4,6-二芳基-5-烷基-3a-(4-甲氧基苯基)-吡咯并[3 ,4-d]异噻唑1,1-二氧化物8。研究了环加合物对高温和/或碱性条件的行为。在这些条件下,初级产物损失了SO 2和二乙基氰胺,得到了1-烷基-2,3,5-三芳基吡咯9和1H-2,3,5-三芳基吡咯10。发现后者可以通过N-保护的环加合物8的热分解并随后将最终的吡咯脱保护而更好地获得。