C-23-MODIFIED DERIVATIVE OF OMT

C-23-Modified derivatives of 5-O-mycaminosyl-tylonolide (OMT) of the formula: 1 wherein R is chloro, fluoro, -S-R4, azido, -NHR5, pyridinium, or -OSO2CF3; R1 is hydrogen, optionally substituted C1-C5-alkanoyl or optionally substituted benzoyl, phenylacetyl, phenylpropionyl, phenoxyacetyl or phenylthioacetyl; R2 and R3 are hydrogen, optionally substituted C1-C5-alkanoyl or optionally substituted benzoyl, phenylacetyl or phenylpropionyl; R4 is hydrogen, optionally substituted C1-C6-alkyl, cyclohexyl, C1-C5 alkanoyl, optionally substituted phenyl or benzyl, or an optionally substituted heteroaryl group selected from imidazolyl, pyrazolyl, pyridyl, pyrimidyl, pyrazinyl, pyridazinyl, triazinyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, thiadiazolyl, thienyl and furanyl; and R5 is hydrogen or an acyl group selected from optionally substituted C1-C5-alkanoyl, optionally substituted benzoyl, phenylacetyl, or phenylpropionyl or optionally substituted phenylglycyl or phenylalanyl; and of the formula: 2 wherein: R6 and R7 together form a CH2= group or R6 is R8O- and R7 is methyl; R8 is C1-C4-alkyl, benzyl or phenethyl; and R1, R2 and R3 are as defined in formula 1; and salts thereof are useful antibiotics or intermediates to antibiotics.