To obtain a new 12,13-epoxytylosin derivative having antimicrobial action and useful as an intermediate, etc., for producing antimicrobial agents and new tylosin derivatives by selectively oxidizing a diene part of 16 membered tylosin ring compound which is a macrolide-based antibiotic compound.

This new 12,13-epoxytylosin derivative is expressed by formula I [R is O or NOH; R1 is CHO or CH(OCH3)2; R2 is H or mycarosyl of formula II; a broken line is a single bond or a double bond] and this new compound is expressed by formula III (R is H or mycarosyl). They have antimicrobial action and useful as intermediates for producing antimicrobial agents and new tylosin derivatives. These compounds expressed by formula I and formula III are obtained by hydrogenating a compound of formula IV [R is CHO or CH (OCH3)2; R1 is H or micarosyl; R2 is N(CH3)2 or N-O(CH3)2] with hydrogen in an organic solvent at an ambient temperature in the presence of Pt-supporting carbon to obtain a compound of formula I, which is reacted with hydroxylamine hydrogen chloride salt and separated by a silica gel chromatography to obtain compounds of formula I and formula III.