GEMINAL VINYL DIAZIDES .10. METHYL 3,3-DIAZIDO-2-CYANOACRYLATE - SYNTHESIS OF VINYL AZIDES, 4,5-DIHYDRO-1H-TETRAZOL-5-YLIDENES, OXAZOLES, AND N-CYANIMINES

Reaction of methyl 3,3-diazido-2-cyanoacrylate (1) with amines 2 at -30-degrees-C yields aminovinyl azides 4. In the presence of equivalent amounts of triethylamine the vinyl azides 4 undergo 1,5'-ring closure to afford the triethylammonium salts 5. Treatment of 5 with hydrochloric acid gives the corresponding 4,5-dihydro-1H-tetrazol-5-ylidene derivatives 6. In contrast thermolysis of 4 leads via azirines 7 to oxazoles 8. Reaction of vinyl diazide 1 with lysine and cystine, respectively, yields bis(vinyl azides) 9. Triethylamine-induced 1,5'-ring closure of 9 produces the bis(triethylammonium) salts 10, which can be transformed under acidic conditions into the corresponding bis(4,5-dihydro-1H-tetrazol-5-ylidene) derivatives 11. With methyl acrylate (17) oxazole 15 reacts via carbonyl ylide 16 in a 1,3-dipolar cycloaddition to give pyrroline 18 (X-ray structure analysis). Thermolysis of the geminal vinyl diazide 1 in the presence of alcohols 19 or primary amines 21 forms the cyanimines 20 and 22, respectively, via methyl 3-aza-2,3-dicyanoacrylate 25. 25 exists as syn/anti isomers which fully agrees with AM1 calculations carried out on cyanimine model systems.