Synthesis of steganacin and derivatives thereof

A process for the preparation of a racemic mixture of the compound having the formula ##STR63## in which Z is OH, oxo (.dbd.O) or OW wherein W is acetyl or ##STR64## and R.sup.1, R.sup.2 and R.sup.3 are alike or different and each is H or (lower)alkyl of 1 to 3 carbon atoms, which process comprises the consecutive steps of

• A. treating the compound having the formula ##STR65## in which R.sup.1, R.sup.2 and R.sup.3 are as defined above, with excess 37% aqueous formaldehdye in the presence of 0.1-2.0M alkali metal hydroxide for about 1 to 48 hours, followed by heating in the presence of excess dilute sulfuric acid and chloroform to produce the compound having the formula ##STR66## in which R.sup.1, R.sup.2 and R.sup.3 are as defined above;
• B. treating compound IV with sodium borohydride in methylene chloride-anhydrous methanol to produce a mixture of the compounds having the formula ##STR67## in which R.sup.1, R.sup.2 and R.sup.3 are as defined above, which mixture is separated into its component parts;
• C. acylating compound III with acetic anhydride, acetyl halide or angelic acid halide in the presence of a tertiary amine to produce the compound having the formula ##STR68## in which W is acetyl or ##STR69## R.sup.1, R.sup.2 and R.sup.3 are as defined above and halide is Cl, Br or I.