Oxidative cyclization by lead(IV) acetate of 1-(4-methoxyphenyl)-4-(tetrazol-5-ylmethyl)azetidin-2-ones to 3-methoxy-9,9a-dihydroazeto[1,2-a]tetrazolo-[5,1-d][1,5]benzodiazepin-11(10H)-ones and related reactions
The tetrazolyl groups of azetidin-2-ones 1a-e and 1h interfere with the normal reaction of related azetidin-2-ones with lead(IV) acetate, viz. acetoxylation at C-4, and cause formation of tetracyclic products 3a-e and 3h. Similar reactions take place with ring homologues 1f, 1g and 1i, and with open-chain analogues 11a and 11b.