Diazoalkanes. Part I. Reaction of Diazomethane with Methyl Ether of Cyclic Hydroxy methyleneketones

Methyl ethers of cyclic α-hydroxymethyleneketones ( \(\beta\)-oxoaldehydes) have been found to react with diazomethane leading to \(\bigtriangleup\)1-pyrazolines which readily undergo elimination of nitrogen to afford \(\beta\)-methylated products. The latter on hydrolysis furnish α-acetylketones and it thus constitutes a simple method for the preparation of α-acetylketones from the readily accessible \(\beta\)-oxo-aldehydes. A convenient preparation of methyl ether of hydroxymethyIeneketones and their probable configuration have also been described. A preliminary account has already been published