A convenient CeCl3·7H2O/NaI-promoted synthesis of structurally novel and strained tricyclic β-lactams from hydrazines

✍ Scribed by Lal Dhar S. Yadav; Vijai K. Rai

• Publisher: Elsevier Science
• Year: 2008
• Tongue: French
• Weight: 186 KB
• Volume: 49
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/j.tetlet.2008.07.068

✦ Synopsis

A convenient synthetic protocol for structurally novel and strained highly derivatized tricyclic b-lactams has been developed. The synthesis involves CeCl 3 Á7H 2 O/NaI catalyzed addition-condensation of mercaptoacetic acid and N-aroyl-N 0 -arylidenehydrazines followed by intramolecular cyclodehydration to afford bicyclic 5H-thiazolo[4,3-b][1,3,4]-oxadiazoles, which on treatment with acid chlorides in the presence of triethylamine furnish highly derivatized tricyclic 3H-azetidino[2,1-b]-thiazolo [3,4-d][1,3,4]-oxadiazol-6ones in 80-93% yields. The process presents an excellent illustration of Ce(III)-catalyzed C-C, C-N and C-S bond formation in a one-pot procedure.