Acetic Acid → HCID 10062362, compound

Participants

Reaction Steps

While stirring and ice cooling, a cold saturated aqueous solution of 42 g (0.6 mol) sodium nitrite was added so slowly drop-by-drop to a solution of 104.4 g (0.6 mol) methoxypentanoic acid ethyl ester in 450 mL of glacial acetic acid, that no noticeable NOX development was detected. The solution was stirred for two hours and treated with 83.2 g (0.64 mol) acetoacetic acid ethyl ester. Then while stirring vigorously, a mixture of 80 g (1.22 mol) of zinc powder and 100 g (1.22 mol) sodium acetate was added in portions within 40 minutes. The inner temperature ranged from 80° to 85° C., a state that was reached by cooling occasionally. Following completion of the addition, the solution was stirred another 30 minutes and then filtered from the nonreacted zinc. The warm solution was poured into 4 L of water and left standing overnight to complete the precipitation. The raw product was filtered off, washed with a little ice cold ether, dried over P4O10 under vacuum for one day, and recrystallized from ethanol/water. Thus, 113.2 g (0.4 mol) 2,4-bis(ethoxycarbonyl)-3-methoxyethyl-5-methylpyrrole (2b) was obtained as colorless needles with a melting point of 86° C. Yield: 65 % based on (1b). For further reaction of (2b) it was not necessary to recrystallize the raw product from ethanol/water.

Provenance & Evidence