Veratrole → N-Boc-(2,3-dimethoxyphenyl)-4-piperidinylmethanone

Participants

Reaction Conditions

Reaction Steps

A suitable reactor maintained under nitrogen is charged with veratrole (12.5 kg, 90.0 mol) and about 87 kg of tetrahydrofuran. The solution is cooled and maintained below −10° C. while adding n-butyl lithium (22.9 kg, 83.3 mol, 23.3% solution in hexane). The mixture is warmed to about 0° C. for 1 hour, then to about 25° C. for at least 2 hours. In a separate reactor maintained under nitrogen is charged with 4-[(methoxymethylamino)carbonyl]-1-piperidinecarboxylic acid, 1,1-dimethylethyl ester (15) as a heptanes wet cake (15.6 kg, 57.3 mol, dry weight basis) and about 66 kg of tetrahydrofuran. The mixture is cooled below −10° C.1 and the lithiated veratrole solution is added at such a rate to maintain the temperature below −10° C. The mixture is warmed to about 25° C. for at least 6 hours.2 When complete, the title compound may be utilized in Scheme H, step a, Example 108 as the reaction solution. 1The solution is sampled and analyzed by GC to determine the amount of 4-[(methoxymethylamino)carbonyl]-1-piperidinecarboxylic acid, 1,1-dimethylethyl ester (15) present.2The solution is sampled and analyzed by GC to confirm the complete formation of 4-(2,3-dimethoxybenzoyl)-1-piperidinecarboxylic acid, 1,1-dimethylethyl ester (7). The reaction is complete if less than 3 area % of 4-[(methoxymethylamino)carbonyl]-1-piperidinecarboxylic acid, 1,1-dimethylethyl ester (15) is detected.

Provenance & Evidence