There is provides a process for the preparation of a compound of formula (7): wherein R is an optionally substituted hydrocarbyl group or an optionally substituted heterocyclic group; provides that R is not a compound of Formula (a): wherein Ra represents an alkyl group, such as a C1-16 alkyl group, and preferably an isopropyl group; Rb represents an aryl group, preferably a 4-fluorophenyl group; Rc represents hydrogen, a protecting group or an alkyl group, such as a C1-16 alkyl group, and preferably a methyl group; and Rd represents hydrogen, a protecting group or a SO2Re group where Re is an alkyl group, such as a C1-16 alkyl group, and preferably a methyl group.