PSP	Synthesis 2003: 1916-1919 DOI: 10.1055/s-2003-41037
© Georg Thieme Verlag Stuttgart · New York
New Protocol for Efficient N-Chlorinations of Amides and Carbamates [1]
Oleg V. Larionov, Sergei I. Kozhushkov, Armin de Meijere*
Institut für Organische Chemie der Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany Fax: +49(551)399475; e-Mail: Armin.deMeijere@chemie.uni-goettingen.de;
Received 12 May 2003

Abstract

N-Chlorination of various amides, carbamates and lactams with inexpensive and stable calcium hypochlorite on moist alumina proceeds smoothly and efficiently, e.g. the technically important 1-chlorohexahydroazepin-2-one (3-Cl) and 1-chloropyrrolidin-2-one (7-Cl) were obtained in 95% and 98% yield, respectively. Excellent results were also observed for the N-chlorination of protected amino acid esters with a cyclopropane moiety to give derivatives such as methyl (tert-butoxycarbonylchloroamino)cyclopropylacetate (1-Cl), methyl (benzyloxycarbonylchloroamino)cyclopropylacetate (2-Cl), methyl 1-(tert-butoxycarbonylchloroamino)cyclopropanecarboxylate (5-Cl) and methyl trans-2-(tert-butoxycarbonylchloroamino)cyclopropanecarboxylate (6-Cl) in 99%, 96%, 90% and 97% yield, respectively.

Key words

amides - amino acids - N-chlorination - calcium hypochlorite - alumina