or more polar protic solvents for example methanol ethanol propanol isopropanol or butanol the compound of formula 46 can also be prepared according to for example scheme viiia thus reaction of a compound of formula 42 with phenyl chloroformate can give a compound of formula 42b which on reaction with an amine of formula r 6 nh 2 can give a compound of formula 45 which can be deprotected to give a compound of formula 46 the reaction of a compound of formula 42 with phenyl chloroformate can be carried out in one or more solvents for example chlorinated solvents e g dichloromethane dichloroethane chloroform or tetrachloromethane nitriles e g acetonitrile or propionitrile or in mixture thereof the compound of formula 42b can be reacted in the presence of one or more bases for example triethylamine trimethylamine or pyridine in one or more chlorinated solvents for example dichloromethane dichloroethane chloroform or carbon tetrachloride the compound of formula 45 can be deprotected in the presence of one or more acids for example organic acids e g trifluoro acetic or acetic acid mineral acids e g hydrochloric hydrobromic or hydroiodic acid or in mixture thereof in one or more polar protic solvents for example methanol ethanol propanol isopropanol butanol or water the compound of formula 51 can be prepared according to for example scheme ix thus reaction of a compound of formula 47 with a compound of formula 24 can give a compound of formula 48 which on protection can give a compound of formula 49 which on.