ChemInform Abstract: REACTION OF KETENE AMINALS WITH ISOCYANATES

Abstract

Die 2,2‐Bis‐[carboalkoxy]‐ketenarninale (I) reagieren mit äquimolaren Mengen von Arylisocyanaten in siedendem Chlorbenzol (3‐4 h) unter Bildung der Tetrahydropyrimidindione (II).

Synthesis and properties of β,β-bisfunctionalised keteneN,N-acetals

“…The synthesis of pyrazolylbenzoimidazole 137 is based on the reaction of gem-formyl groups of the starting benzoimidazole with hydrazine hydrate. 106 Several studies 171,172 dealt with the synthesis of imidazole derivatives from `push-pull' enamines (see also Ref. 18).…”

“…For example, the reaction of ethyl diaminomethylenecyanoacetate with phosgene or diethyl oxalate results in imidazolidinediones. 171 Imidazoles are formed from salts of alkyl dicyanoacetate or tricyanomethane and amino acids, 172 ketene aminals being the intermediate products.…”

“…86 Similar replacement of the CCl 3 and CF 3 groups in enamines by the amino groups with the formation vicinal ethylenediamine derivatives has been reported. 87,88 Reactions of trichloromethyldialkylamines 58 with compounds containing reactive methylene groups also result in ketene N,N-acetals. 89 For example, compounds 58 react with malonodi-nitrile to give chloroenamines 59.…”

“…151 The reaction of b,b-disubstituted ketene N,N-acetals with acyl halides results in N-acylation products. 88 If dimethyltrichloromethylamine is used as the acylating reagent, the reaction occurs at the nitrogen atom to give the derivative 109 containing the chloroformamidine moiety.…”

“…Four-membered heterocycles Benzoylation of ketene aminals results in azetine derivatives. 88 The formation of diazetidine derivatives 131 has been discussed above (see Section II.8).…”