Debenzylation of N-Benzyl-b-lactams by Use of Anodic Oxidation
1985; Elsevier BV; Volume: 23; Issue: 2 Linguagem: Inglês
10.3987/r-1985-02-0317
ISSN1881-0942
Autores Tópico(s)Asymmetric Synthesis and Catalysis
ResumoAnodic oxidation of N-benzyl-3-methylene-0-lactam la .followedby hydrolysis with TsOH in 2-butanone gave 3-methylene-Blactam 4?.To examine the effect of the substltuents on the aromatic ring of N-benzyl group for the anodic oxidation, N-p-carbomethoxy, N-p-methyl and N-p-methoxybenryl-3-methylene-6-lactams were electrolyzed under the same conditions.N-p-Methyl and N-pmethoxybenzyl-@-lactams gave only the exo-methoxylated compounds.In the previous paper, it has been shown that the anodlc oxidation of N-alkyl-B-lactams 1 in MeOH afforded the methoxylated compounds 2 and 3 at the exo---.and endo-cyclic carbons w to nitrogen, though five, six and seven membered lactams were regioselectively electrolyzed under the same conditions.'It was very interesting that the major product on the electrochemical oxidation of Nbenzyl-3-methylene-6-lactam(la) was methoxylated compound 2a at the exo--... p o s i t ~o n .~ If the acid treatment of this compound 2a could afford N-non--substituted-6-lactam 4a, the anodic oxidation might be a useful method for -debenzylation of N-benryl-6-lactams.3 4 Thus, a solution of N-benzyl-3-methylene-~-lactam (la, 85 mg, 0.49 mmol) was .electrolyzed in MeOH(6 mll containing Et4NC1O4(0.1 mol solutionl in an undivided cell with platinum plates as anode and cathode under constant current130 mA, 4.4 F/mol) to afford N-methoxybenzyl-3-methy1enee6-1actam~2a, 55 mg, 54 8 1 , N--. b e n z y l -3 -m e t h y l e n e -4 -m e t h o x ~B -l a c t a m ( 3 a , 12 my, 12 % ) and the starting
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