@jauhar123 | Posted 14 Mar. 2019
2-Chloro-4-methylpyridine (2-Chloro-4-picoline) reacts with 3,5-bis(trifluoromethyl)phenylboronic acid to form 2-(3,5-bis(trifluoromethyl)phenyl)-4-methylpyridine by palladium-catalyzed cross-coupling reaction.
2-Chloro-4-picoline (2-Chloro-4-methylpyridine) has used in the determination of gas-phase basicity of several relatively small organic molecules used in the MALD.
In the preparation of 2-chloro-4-methylpyridine of the formula ##STR6## by reacting 3-methylpyridine 1-oxide with phosphorus oxychloride, the increase which comprises leading out the reaction in the presence of an underlying organic nitrogen mixture and in the presence of a diluent at a temperature between about -50° C. and +50° C.
The 2-chloro-4-methylpyridine is obtained in addition to 2-chloro-3-methylpyridine, 4-chloro-3-methylpyridine and 3-chloro-5-methylpyridine by reacting 3-methylpyridine 1-oxide with phosphorus oxychloride. The main result of this reaction is 4-chloro-3-methylpyridine; the percentage of 2-chloro-4-methylpyridine is in general below 25%.
A novel process for the preparation of 2-chloro-4-methylpyridine of the formula (I) ##STR2## from 3-methylpyridine 1-oxide of the formula II) ##STR3## and phosphorus oxychloride has now been found, which described in that the reaction is conducted out in the presence of an underlying organic nitrogen compound and in the presence of a diluent at temp between -50° C. and +50° C.
It is surprising that the preparation for this basic organic nitrogen compounds, 2-chloro-4-methylpyridine can be taken in a significantly higher yield than by the hitherto known method since by using phosphorus oxychloride and basic organic nitrogen mixtures together, by-products from the reaction of these ingredients with one another were more likely to occur.