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US 6,635,763 B2Granted
Process to prepare clopidogrel
AssigneeCadila Health Care Limited
InventorsBipin Pandey, Vidya Bhushan Lohray, Braj Bhushan Lohray
Life of this patent
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Abstract
The present invention relates to a process for the preparation of thieno[3,2-c]pyridine derivatives having pharmacologically significant anti-aggregating and anti-thrombotic properties.
Claims28
A process for the preparation of compound of formula (I),
- where X represents either hydrogen, fluoro, chloro, bromo or iodo atom which comprises:
- i) reacting a compound of formula (V) or its salt,
- with a cyanide of general formula (VII) where M represents alkali metal, trimethysilyl, Cu, or hydrogen, followed by addition of compound of general formula (VI), where X is as defined earlier, to obtain a racemic compound of general formula (IV), where X is as defined earlier;
- ii) reacting a compound of general formula (IV), in (±) form or any of its optically active (+), or (−) forms,
- with acidic or basic reagents to obtain a compound of formula (II) or its salt with retention of configuration;
- iii) reacting a compound of general formula (II), in either (±) form or its optically active (+) or (−) forms;
- with acidic reagents in presence of methanol to obtain a compound of formula (I) or its salt, with retention of configuration;
- and
- iv) resolving the (±) form of the compound of formula (I) or its salt if formed into its optical isomers.
6 more elements
A process for the preparation of compound of formula (III) or its salt, where X represents hydrogen, chloro, bromo or iodo atom which comprises:
- i) reacting a compound of general formula (IV) or salt thereof, in any of its optical forms, in presence of acidic/basic catalyst in a suitable solvent, giving the corresponding acid of formula (III) or its salt, with a configuration that is the same as that of the starting material;
- and
- ii) optionally resolving any racemic compound of formula (III) or its salt, into its corresponding optically pure (+) and (−) forms.
A process for the preparation of a compound of formula (IV) and its salts,
- where X represents a halogen atom such as chloro, bromo, iodo substituent which comprises:
- i) reacting a compound of general formula (V) or its acid addition salt with a cyanide of general formula (VII), wherein M is selected from the group consisting of:
- alkali metal, TMS, Cu, and hydrogen, followed by reaction with a halogenobenzaldehyde of the formula (VI), wherein X is halogen atom;
- or
- ii) reacting a halogenobenzaldehyde of general formula (VI), wherein the meaning of X is halogen atom, with cyanide of general formula (VII), wherein M is selected from the group consisting of:
- alkali metal, TMS, Cu, and hydrogen, followed by in situ reaction with the compound of general formula (V) or its acid addition salt;
- or,
- iii) reacting a halogenobenzaldehyde of general formula (VI) wherein the meaning of X is halogen atom, with hydrogen sulfite of general formula (VIII),
- M′HSO3 (VIII)
- wherein M is selected from the group consisting of:
- alkali metal, TMS, Cu, and hydrogen, and then with cyanide of general formula (VII), wherein M is selected from the group consisting of:
- alkali metal, TMS, Cu, and hydrogen, and subsequently reacting in situ with the compound of general formula (V) or its acid addition salt followed by resolving of the compound of formula (IV) or its salt, so as to obtain to its optically pure (+) and (−) form.
9 more elements
Dependencies are inferred from the claim text.