Simple and condensed β-lactams. Part 33. AlCl3 catalyzed ring closures of some 3-aryloxy-4-oxoazetidine-2-carboxylic chlorides to 1H-chromeno[3,2-b]azete-2,8(2aH,8aH)-diones and some reactions of the products

✍ Scribed by Ferenc Bertha; József Fetter; Mária Kajtár-Peredy; Károly Lempert

• Publisher: Elsevier Science
• Year: 1999
• Tongue: French
• Weight: 749 KB
• Volume: 55
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(99)00222-7

✦ Synopsis

Carboxylic chlorides 3a-3c, when treated with AIC13, afforded the tricyclic compounds 17a-17c. NaBH4 reduction of 17a and 17b afforded compounds 1 la and lib. The latter and the related known compounds 4a, 5b, 6a and 7a were used for the preparation of various dihydrochromeno[3,2-b]azet-2(lH)-ones and of a 3A-disubstituted chromane-2-carboxylic ester (26) of fixed stereochemistry. Catalytic reduction of 8-chloro compound 5b afforded compounds 10b and 25, the products of simple hydrodechlorination and of azetidinone ring cleavage with concomitant hydrodechlorination, respectively, o 1999 Elsevier Science Ltd. All rights reserved.