| abstract |
Title cpds. are of formula (I) (R1 = H, CH3, C2H5 or 1-4C acyl opt. substd. with CH3O or C2H5O; R2 = lower alkyl; R3 = CH3, HCO or CH2OH; R4 = H or OH and R5 and R6 = H, OH, or CH3CO2) and they are prepd. by reacting corresp. 2',3'-dihydroxy cpd. where R3 = CH3 or CHO with a trialkylorthoformate in presence of an acid catalyst opt. followed by redn. of (I, R3 = CHO) to (I, R3 = CH2OH). |