3-Diethylamino-4-(4-methoxyphenyl)-isothiazole 1,1-dioxide (3) readily reacts with oxazolones 2 and munchnones 7 affording with satisfactory yield 3-diethylamino-4,6-diaryl-3a,4-dihydro-3a-(4-methoxyphenyl)-6aH-pyrrol o[3,4-d]isothiazole 1,1-dioxides 4 and 3-diethylamino-4,6-diaryl-5-alkyl-3a-(4-methoxyphenyl)-pyrrolo[3,4-d]i sothiazole 1,1-dioxides 8, respectively. The behaviour of the cycloadducts towards elevated temperatures and/or basic conditions was investigated. Under these conditions the primary products lost SO2 and diethylcyanamide affording 1-alkyl-2,3,5-triarylpyrroles 9 and 1H-2,3,5-triarylpyrroles 10. These latter were found to be better obtained through thermal decompression of N-protected cycloadducts 8 and subsequent deprotecting the final pyrroles.
Isothiazoles. Part IV. Cycloaddition reactions of diaryl-oxazolones and munchnones to 3-diethylamino-4-(4-methoxyphenyl)-isothiazole 1,1-dioxide: A new synthesis of triarylpyrroles / P. Baggi, F. Clerici, M.L. Gelmi, S. Mottadelli. - In: TETRAHEDRON. - ISSN 0040-4020. - 51:8(1995), pp. 2455-2466. [10.1016/0040-4020(94)01110-L]
Isothiazoles. Part IV. Cycloaddition reactions of diaryl-oxazolones and munchnones to 3-diethylamino-4-(4-methoxyphenyl)-isothiazole 1,1-dioxide: A new synthesis of triarylpyrroles
F. ClericiSecondo
;M.L. GelmiPenultimo
;
1995
Abstract
3-Diethylamino-4-(4-methoxyphenyl)-isothiazole 1,1-dioxide (3) readily reacts with oxazolones 2 and munchnones 7 affording with satisfactory yield 3-diethylamino-4,6-diaryl-3a,4-dihydro-3a-(4-methoxyphenyl)-6aH-pyrrol o[3,4-d]isothiazole 1,1-dioxides 4 and 3-diethylamino-4,6-diaryl-5-alkyl-3a-(4-methoxyphenyl)-pyrrolo[3,4-d]i sothiazole 1,1-dioxides 8, respectively. The behaviour of the cycloadducts towards elevated temperatures and/or basic conditions was investigated. Under these conditions the primary products lost SO2 and diethylcyanamide affording 1-alkyl-2,3,5-triarylpyrroles 9 and 1H-2,3,5-triarylpyrroles 10. These latter were found to be better obtained through thermal decompression of N-protected cycloadducts 8 and subsequent deprotecting the final pyrroles.Pubblicazioni consigliate
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