Über Thioacyl‐isocyanate, XVII. Reaktion des Ethoxy(thiocarbonyl)‐isocyanats mit Vinylethern

Abstract

Offenkettige und cyclische Vinylether ergaben mit Ethoxy(thiocarbony1)-isocyanat (5) nebeneinander Dihydro-1,3-thiazinone (1, 3, 6, 8) und ungesattigte Carboxamide (2, 4, 7, 9). Spektroskopisch machte man in einigen Fallen P-Lactame in geringer Konzentration wahrscheinlich. Die Cycloaddition erfolgte regiospezifisch nach der vorgegebenen Polaritat; sie ergab mit Dihydropyran den Bicyclus 6 rnit cis-verknupften Ringen. Thioacyl Isocyanates, XVII Reaction of Ethoxy(thiocarbony1) Isocyanate with Vinyl EthersEthoxy(thiocarbony1) isocyanate (5) reacts with linear and cyclic vinyl ethers to give dihydro-I ,3-thiazinones (1, 3, 6, 8) besides unsaturated carboxamides (2, 4, 7, 9). In some cases P-lactams in low concentrations probably originated (spectroscopy). The cycloaddition occurred regiospecifically according to the polarity; it afforded with dihydropyran the bicyclic compound 6 with cisbonded rings.In der XV. Mitteilung wurde an drei Beispielen gezeigt, dal3 Thiobenzoyl-isocyanat mit Vinylethern zu 1,3-Thiazinon-Derivaten reagiert 3); es interessierte die Frage, ob Ethoxy(thiocarbony1)-isocyanat (5) mit seiner modifizierten Thion-Gruppe gleichartiges Verhalten aufweist. Die hierfiir eingesetzten Vinylether sind aus Schema 1 zu ersehen.Zur praktischen Durchfiihrung wurde das Isocyanat thermisch aus seinem Dimeren erzeugt ') und in einen 4 -5fach molaren Uberschul3 des Vinylethers destilliert. Der VerChem.

Synthesis and chemical characteristics of 2-substituted thiazoline-4,5-diones. (Review)

“…In this reaction 2,3-dihydro-1,4-dioxin only forms the C-addition product 42, while 1-ethoxy-2-methylethylene forms the [4+2] cycloaddition product 43 [18]. Numerous examples of the similar reaction of thiobenzoyl isocyanate 2 with vinyl ethers and sulfides and also with substituted acetylenes, leading to the cyclic products 44-53, are described in [17,18]. Norbornene and norbornadiene form the cycloadducts 54 [9,20] and 55 [20] respectively.…”

“…It is interesting that diazoacetophenone plays the role of C-nucleophile during the reaction with the isocyanate 2 (Ar = Ph) and reacts with the formation of compound 35 [16]. In this reaction 2,3-dihydro-1,4-dioxin only forms the C-addition product 42, while 1-ethoxy-2-methylethylene forms the [4+2] cycloaddition product 43 [18]. Numerous examples of the similar reaction of thiobenzoyl isocyanate 2 with vinyl ethers and sulfides and also with substituted acetylenes, leading to the cyclic products 44-53, are described in [17,18].…”

“…butyl vinyl ethers, 3,4-dihydropyran, and 1-ethoxycyclohexene react with ethoxydithiocarbonyl isocyanate 13 simultaneously as CH nucleophiles and dienophiles with the formation of compounds 36-41[18…”