title: New entry for synthesis of N-acylhydrazones, pyridazinones, and 1,3,4-oxadiazin-6-ones from alpha-amino acid esters.
abstract: Versatile electrophiles N-acylhydrazones are synthesized via diazotization, reduction, and acylation of alpha-amino acid esters. Reduction of diazo esters with L-selectride or tributylphosphine affords the corresponding hydrazones in good yields. Both reducing agents give anti-hydrazones as the major product although the reactivity of each reductant is slightly different. The resulting hydrazones are acylated to give N-acylhydrazones, which are subjected to further reactions to give 1,3,4-oxadiazin-6-ones that serve as useful synthetic intermediates for the Diels-Alder reaction.
authors.affiliation: Department of Pharmaceutical Science, Musashino University, Shinmachi, Nishitokyo, Tokyo, Japan.
authors.forename: Eiko
authors.initials: E
authors.lastname: Yasui
authors.forename: Masao
authors.initials: M
authors.lastname: Wada
authors.forename: Norio
authors.initials: N
authors.lastname: Takamura
mesh_terms: D000215:Acylation; D000596:Amino Acids / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry; D004952:Esters / Q000737:chemistry*; D006835:Hydrazones / Q000138:chemical synthesis*; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D010078:Oxazines / Q000737:chemistry*; D010084:Oxidation-Reduction; D011724:Pyridazines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D001391:Azo Compounds; D004952:Esters; D006835:Hydrazones; D010078:Oxazines; D011724:Pyridazines