2-Pyrrolidones aziridines

Thermolysis of the aziridine (446) in the presence of diphenylketene gave a mixture of the pyrrolidone (447 minor product) and the oxazolidine (448 major product). In this instance the preferential addition to the C=0 bond is explained in terms of steric effects (72CC199). Similar addition to diphenylacetaldehyde takes place with the same orientation and the oxazolidine (448a) was obtained. When the reaction of the aziridine with the aldehyde was carried out in the presence of hydrogen selenide a selenazolidine was obtained (72BSB295). 

Carbanions of active methylene compounds also react with aziridine-2-car-boxylic esters to give ring-opened products [129]. The ring-opened intermediates usually cyclize spontaneously to pyrrolidones. Treatment of 190 (Scheme 3.70) with the sodium enolate of dimethyl malonate 191, for example, afforded pyrroli-done 192 in 15% isolated yield, together with 30% of the debenzoylated product 193. 

Thermolysis of the aziridine (225) with diphenylketene gave the pyrrolidone (226 minor product) and the oxazolidine (227 major product). 

Yang, D., and B.R. Mattes. 1999. Investigation of gel inhibitor assisted dissolution of polyaniline A case study for emeraldine base, 2-methyl-aziridine, and N-methyl-pyrrolidone. Synth Met... 

Stamm and his co-workers have shown that pyrrolidones can be obtained from aziridines by reaction with sodium enolates of simple esters, and if or R = H in (99), then further amidoethylation can result. 

All lower lactams have strained rings but with some differences among them aziridin-2-one and azetidin-2-one are highly strained, while 2-pyrrolidone and 2-piperidone have weakly strained rings. The stability of the highly strained lactams maybe increased by substitution in fact, aziridin-2-one is known only in the substituted form. 

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