| abstract |
A method of synthesising a compound of formula (1), in which each of R?1 and R2¿ is independently selected from H or optionally substituted straight or branched chain C¿1?-C30 alkyl, C1-C30 carboxyalkyl, C1-C30 sulphoxyalkyl, C1-C30 alkoxy, C3-C30 cycloalkyl, C3-C30 carboxycycloalkyl, C3-C30 sulphoxycycloalkyl, C3-C30 cycloalkoxy, heterocyclic, carboxyheterocyclic, sulphoxyheterocyclic, oxyheterocylic, C3-C30 cycloalkenyl, carboxycycloalkenyl, sulphoxycycloalkenyl or cycloalkenoxy, C8-C30 cycloalkynyl, carboxycycloalkynyl, sulphoxycycloalkynyl or cycloalkynoxy, C2-C30 alkynyl, carboxyalkynyl, sulphoxyalkynyl or alkynoxy group, C4-C30 aromatic, carboxyaromatic, sulphoxyaromatic or aryloxy, C4-C30 heteroaromatic, carboxyheteroaromatic, sulphoxyheteroaromatic or heteroaryloxy group, wherein in any of the hereto atom-containing groups the hetero atom is selected from O, S, and N; comprises treating a compound of formula (2) with a reducing system effective to reduce preferentially the compound of formula (2) at the 2-position to produce the compound of formula (1), wherein the reducing system comprises (i) hydrogen in the presence of a platinum-containing catalyst, or (ii) a hybride source in the presence of a transition metal phthalocyanine or polyphthalocyanine in which the transition metal is iron and/or cobalt. |