摘要:
Provided is a method of selectively enzymatically esterifying or selectively enzymatically solvolyzing epimers of analogs of vitamin D having a stereogenic center at C-24 that has a free or esterified OH group. The method can be used, for example, for separating mixed epimers of the vitamin D analog.
摘要:
The present invention provides methods of purifying montelukast, a new isolated impurity of montelukast of formula I, method for its isolation, and method of using montelukast impurity as a reference marker and a reference standard.
摘要:
Provided is a method of selectively enzymatically esterifying or selectively enzymatically solvolyzing epimers of analogs of vitamin D having a stereogenic center at C-24 that has a free or esterified OH group. The method can be used, for example, for separating mixed epimers of the vitamin D analog.
摘要:
The present invention provides processes of preparing 3-(2-chloroethyl)- 6,7,8,9-tetrahydro-9-hydroxy-2-methyl-4H-pyrrido[ 1,2-a]- pyrimidin-4-one (CMHTP) useful as intermediates for the preparation of paliperidone, wherein the processes use 3-(2-chloroethyl)-2-methyl-9-benzyloxy-4H-pyrido[ 1,2-a]pyrimidine-4- one (CMBP) and/or 3-(2-chloroethyl)-2-methyl-9-hydoxy-4H-pyrido[l,2- a]pyrimidine-4-one (CMHP) having phosphorus at least partially removed as the intermediate.
摘要:
The present invention provides methods of purifying montelukast, a new isolated impurity of montelukast of formula I, method for its isolation, and method of using montelukast impurity as a reference marker and a reference standard.
摘要:
Provided is a process for preparation of an intermediate in the synthesis of nateglinide. Trans-4-isopropylcyclohexane acid chloride is formed by reacting 4-isopropylcyclohexanecarboxyl acid with thionyl chloride in the presence of an effective amount of an organic amide. Also provided are processes for preparation of nateglinide by acylation of a suitable salt of D-phenylalanine with trans-4-isopropylcyclohexane acid chloride in both a single and a two phase system, and in water free of a co-solvent.