ISSN:
0021-8383
Schlagwort(e):
Chemistry
;
Organic Chemistry
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
The Dehydration of Ureas by Two-Phase Dichlorocarbene Reaction, a Synthetic Access to Substituted CyanamidesA wide variety of N,N-disubstituted ureas are dehydrated in the CHCl3/NaOH catalytic two-phase system under mild conditions. The sequence of urea-transamidation and dehydration thus offers a profitable approach to aprotic cyanamides. Among various tested PT-catalysts tertiary amines prove to be the most efficient and favourable ones. Tertiary amines may also be used advantageously in the transformation of carboxylic amides and thioamides to the corresponding nitriles. The application of the same technique is less suitable in the case of N-mono-substituted ureas, N,N′- disubstituted ureas as well as N(dialkylaminomethylidene) ureas, because consequent reactions of the primarily formed cyanamides predominate. Problems concerning the dehydration mechanism are elucidated in terms of HMO-perturbation theory
Zusätzliches Material:
4 Tab.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/prac.19833250512
