Katsura Morita

A new 1,3-dipolar cycloaddition reaction : Synthesis of some isoxazolidine derivatives

Abstract A new 1,3-dipolar cycloaddition reaction with formaldoxime as a 1,3-dipole compound has been discovered. Stereospecificity of the reaction and mass spectral data are discussed. With ethyl propiolate, 3,5-diethoxycarbonylpyridine, formed via a 1,4-dipolar cycloaddition reaction, was obtained.

A novel photo-induced methylation of pyrimidines and condensed pyrimidines☆

Abstract A new photo-induced methylation of pyrimidines and condensed pyrimidines by irradiating an acidic solution of the bases in methanol is described. The scope and limitation, effects of acids, the calculation of the reactivity indices by the MO method, effect of bases on ·CH2OH radical formation, and the reaction mechanism are discussed.

The reactions of chromomycinone and derivatives

Abstract The various reactions of chromomycinone, the chromophore of the cancerostatic chromomycins, are described. The structures of several chromomycinone derivatives are also discussed.

The stereochemistry of chromomycinone and a note on the benzoate rule

Abstract It has been shown that chromomycinone can be represented by the absolute configurational structure 1. Molecular rotation differences between the acetate and benzoate of secondary alcohols can be employed for deriving the absolute configuration.

A facile one-step synthesis of adenine

Abstract A facile one-step synthesis of adenine has been achieved by the reaction of formamide with POCl 3 in a sealed tube. A maximum yield reached 43·5% of theory calculated on formamide under optimal conditions. Hydrogen cyanide is not considered a possible intermediate for the formation of adenine because H 14 CN added to the reaction mixture is not incorporated. A speculative mechanism for the reaction is proposed.

Reduction of cephalosporanic acids with chromium(II) salts : Synthesis of 3-methylenecepham derivatives☆

Abstract 7-Acylaminocephalosporanic acid derivatives (1) were converted into 7-acylamino-3-methylenecepham-4-carboxylic acids (2) by treatment with chromium(II) salts in aqueous media. The esters (4a or 4b) of 7-acylamino-3-methylenecepham compounds were readily isomerized to the 3-methyl-3-cephem compounds (5a or 5b) under basic conditions. The reaction mechanism is discussed.