Back to results
US 5,292,886 AGranted
Process for the preparation of 2-halomethyl-3,5-dimethyl-4-methoxypyridine halohydrate
OwnerAlberto Palomo Collinventor
Life of this patent
Estimating the term…
Abstract
The process comprises a first step of O-acylation and subsequent acyloxylation of the 2-position methyl group of 2,3,5-trimethyl-4-methoxypyridine N-oxide, to obtain a compound which is subjected to a final halogenation step, in which the 2-position substituent is converted into halomethyl with a halogenating agent.
Claims12
A process for the preparation of 2-chloromethyl-3,5-dimethyl-4-methoxypyridine hydrochloride of formula VI ##STR12## the process comprising:
- acyloxylation of the 2-position methyl group of 2,3,5-trimethyl-4-methoxypyridine N-oxide of formula III ##STR13## by treatment with an acylating agent in the presence of a catalyst, selected from 4-dimethylaminopyridine, 4-guanidinopyridine or 4-pyrrolidinopyridine, to obtain the compound of formula IVa ##STR14## wherein R is methyl, trichloromethyl or trifluoromethyl;
- basic hydrolysis of the formula IVa compound under mild conditions, carried out by adding an aqueous alkaline hydroxide solution having a pH between 11 and 13 in the presence of a cosolvent and at 0.degree. to 75.degree. C., to give 2-hydroxymethyl-3,5-dimethyl-4-methoxypyridine represented by the formula Va ##STR15## which is finally chlorinated with an amidinium chloride to give the 2-chloromethyl-3,5-dimethyl4-methoxypyridine hydrochloride.
Dependencies are inferred from the claim text.