Process for preparing anthracyclinones

A process for the preparation of an anthracyclinone of formula (I):

• ##STR12## wherein R represents a hydrogen atom or a COOR.sub.1 group in which R.sub.1 is a hydrogen atom or a straight or branched alkyl group having from 1 to 10 carbon atoms optionally substituted at one or more carbon(s) in the chain by an aryl, alkoxy, ester or amide group, which process comprises:
• (i) (a) reacting a 4-demethyl-4-sulfonyl-7-deoxy-13-dioxolanyl daunomycinone of formula (V):
• ##STR13## wherein R' represents an alkyl group having from 1 to 10 carbon atoms optionally substituted by one or more halogen atoms or an aryl group optionally substituted by halogen, alkyl, alkoxy or nitro, in a reducing environment with a catalytic amount of a compound of formula (VIII):
• ML.sub.n L'.sub.m (VIII)
• wherein M represents a transition metal atom, L and L', which may be the same or different, each represent an anion or a neutral molecule selected from the group consisting of Cl, CH.sub.3 COO, monophosphine, di-phosphine, phosphite and diamine;
• and n and m may vary from 0 to 4, such as to obtain a compound of formula (VII):
• ##STR14## wherein R represents hydrogen;
• or (b) carbonylating a 4-demethyl-4-sulfonyl-7-deoxy-13-dioxolanyl daunomycinone of formula (V) as defined above, with carbon monoxide in the presence of a nucleophile R.sub.1 OH wherein R.sub.1 is as defined above, an organic or inorganic base and as catalyst a compound of formula (VIII) as defined above, such as to obtain a compound of formula (VII) as shown above wherein R represents a COOR.sub.1 group;
• and
• (ii) introducing an .alpha.-hydroxy group at the 7-position and removing the 13-oxo protecting group by acid hydrolysis from the resultant compound of formula (VII).