5-Methyl-2-pyrazinecarboxylic acid → 2-Pyrazinecarboxylic acid, 5-methyl-, methyl ester

Beteiligte Stoffe

Reaktionsschritte

According to the invention there is provided a process for the preparation of N-[2-[4-(aminosulfonyl)phenyl]ethyl]-5-methylpyrazine-carboxamide of the formula I: ##STR15## consisting of: i) treating 5-methylpyrazine-2-carboxylic acid of the formula VIII: ##STR16## with methanol under reflux to obtain 5-methylpyrazine-2-carboxylic acid methyl ester of the formula VIII A ##STR17## ii) reacting 5-methylpyrazine-2-carboxylic acid methyl ester of the formula VIII A with 2-phenylethylamine of the formula II: ##STR18## at 100° to 200° C. to obtain 5-methylpyrazine 2-(2-phenylethyl) carboxamide of the formula IX: ##STR19## iii) chlorosulfonating the 5-methylpyrazine-2(2-phenylethyl)carboxamide of the formula IX with chlorosulfonic acid at 0°-45° C. to obtain [N-[2-[4-Chlorosulfonyl)phenyl]ethyl]-5-methylpyrazine carboxamide] of the formula X: ##STR20## iv) and treating the (N-[2-[4-(chlorosulfonyl)phenyl]ethyl]-5-methyl pyrazine-carboxamide] of the formula X with ammonia to obtain N-[2-[4-(aminosulfonyl)phenyl]ethyl]-5-methylpyrazine carboxamide of the formula I.

Herkunft & Nachweise