PROCESS FOR THE PREPARATION OF TROMETHAMINE SALT OF (-) 3-4-(2-(5-ETHYL-1-METHYL-7-OXO-3-PROPYL-6,7-DIHYDRO-1H-PYRAZOLO-4,3-DPYRIMIDIN-6-YL)ETHOXY)PHENYL-2-ALKOXYPROPIONIC ACID

摘要

A present invention relates to a process for the preparation of tromethamine salt of (-) 3-[ 4-(2-(5-ethyl-1-methyl- 7-oxo-3-propyl-6, 7-dihydro-1H-pyrazolo- [4,3-d]pyrimidin-6-yl)ethoxy)phenyl]-2-alkoxypropionic acid of the formula (1), where R represents (CSUB1/SUB-CSUB6SUB) alkyl group, comprising three step processes: i) condensing the pyrazolo [4, 3-d]pyrimidin- 7-one of the formula (3), with alkyI3-(4-hydroxyphenyl)-(2S)-2-hydroxy propionate of the formula (4) in the presence of a base and an organic solvent, ii) hydrolysing and etherifying the resulting alkyl (-) 3-[4-(2-( 5-ethyl-l-methyl.- 7- oxo-3-propyl-6, 7 -dihydro-l H -pyrazolo-[ 4,3-d]pyrimidin-6-yl)ethoxy )phenyl]-2- hydroxy propanoate of the formula (5) iii) reacting the resulting (-) 3-[4-(2-(5-ethyl-1-methyl- 7-oxo-3-propyl-6, 7- dihydro-1H -pyrazolo-[ 4,3-d]pyrimidin-6- yl)ethoxy )phenyl]- 2- alkoxypropanoic acid of formula (6) with tromethamine in presence of temperature.