Reaction of 3-aroylaziridines with diphenylcyclopropenone. Synthesis and properties of novel 4-aroyl-4-oxazolines

Abstract

3-Aroylaziridines and 3-acylaziridines react with diphenylcyclopropenone with the formation of novel 4-aroyl-4-oxazolines and 4-acyl-4-oxazolines respectively. The unusual physical and chemical properties of these reactive heterocycles are discussed.

1,3-Dipolar Cycloaddition Reactions of Azomethine Ylides with Carbonyl Dipolarophiles Yielding Oxazolidine Derivatives

“…Two years prior, Lown's research group also reported that azomethine ylides, derived from 3-aroyl-and 3-acylaziridines 23, added to the carbonyl group of diphenylcyclopropenone (3a). This afforded intermediate oxazolidines 27 that were postulated to open to give azomethine ylides 28 and subsequently close onto the adjacent carbonyl group to afford 4-aroyl-and 4-acyl-4-oxazolines 29 (Scheme 5, Table 3) [56,57]. 6 3-NO2-C6H4 C6H11 Ph f (27) 1 7 4-NO2-C6H4 C6H11 Ph g (64)…”

“…oxazolines 29 (Scheme 5, Table 3) [56,57]. Lown and Akhtar went on to examine the thermolysis of cis-3-benzoylaziridine 30 in dry acetonitrile, which predominantly formed an 80:20 mixture of the corresponding stereoisomeric Lown and Akhtar went on to examine the thermolysis of cis-3-benzoylaziridine 30 in dry acetonitrile, which predominantly formed an 80:20 mixture of the corresponding stereoisomeric oxazolidines 31 and 32, respectively, by an autocatalytic partial hydrolytic fragmentation of one molecule of aziridine 30 to give 3-nitrobenzaldehyde (2h) and subsequent 1,3-dipolar cycloaddition of 2h to the azomethine ylide formed from ring opening of another molecule of aziridine 30.…”

1,3-Dipolar cycloaddition reactions of 2-(2′-thienyl)aziridines

“…The 2-(2'-thienyl)aziridine, 1, reacted readily stantially reduced resonance energy compared with diphenylcyclopropenone to give a 1:l with an aryl group. adduct assigned the 2-(2'-thieny1)-4-oxazoline structure 14 on the basis of its dipolarophilic (c) Aryl Isothiocyanates as Dipolarophiles activity (8,9). For example, treatment of 14 with…”

Synthesis and cycloaddition reactions of 2-(2-thienyl)aziridines

“…The latter reaction probably involves thermal isomerization of ethyl maleate to ethyl fumarate at the higher reaction temperature. We have reported the partial isomerization of methyl maleate during the addition to 4-oxazolines to give 3-aroyl-4,5-dihydrofurans (27) and Huisgen et al have observed complete thermal isomerization of methyl maleate in an attempt to observe stereospecific addition of a ketocarbene to maleate and fumarate (28). Adducts 14,15, and 16 prepared by reaction of 1-isopropyl-3-p-phenylbenzoyl-2-(2-thieny1)-aziridine to methyl fumarate, methyl maleate, and maleic anhydride respectively show a pronounced trend towards increasing difference in chemical shift of the non-equivalent N-isopropyl methyl groups (see Fig.…”