Patent ID: 7005516

Claim:
A process for preparing compounds of Formula I: and its pharmaceutically acceptable salts, esters, enantiomers, diastereomers, N-oxides, amides, wherein R is C 1 to C 15 alkyl, alkene, alkyne (straight chain or branched), aryl, substituted aryl or alkylaryl and R 1 is methyl, phenyl o-, m- or p-chlorophenyl, tolyl, methoxyphenyl or nitrophenyl and R 2 is H, pyrrolidinyl, piperidinyl, morpholinyl or hexamethyleneimino or a radical of the formula NHR 3 , wherein R 3 is C 1 to C 15 alkyl, alkene or alkyne (straight chain or branched) or a radical of Formula III: wherein n is 2 to 5 and is a five-, six- or seven-membered heterocyclic ring containing one or more heteroatoms, the process comprising treating the compound of Formula II with an isocyanate in a solvent as follows: