To a solution of N-(1-benzylpiperid-4-yl)-2-methoxy-4-amino-5-nitrobenzamide (3.8 g; 0.01 mole) [prepared as described in Example 1 or 4], in acetone (100 ml) and chloroform (100 ml), methyl iodide (1.25 ml; 0.02 moles) was added. After stirring at room temperature for 8 hours, an additional amount of methyl iodide (1.25 ml; 0.02 moles) was added and the mixture was left at room temperature for another 15 hours and then filtered. A solid was collected which was washed with diethyl ether to give 4.8 g of N-(1-benzylpiperid-4-yl)-2-methoxy-4-amino-5-nitrobenzamide methyl iodide. After recrystallization from a mixture of water-methanol, it melted at 232°-234° C. (dec).
