Hydrochloric Acid → isopropyl 5-benzoyl-7-bromo-1,2-dihydro-3H-pyrrolo[1,2-a]pyrrole-1-carboxylate
Reaction equation
[C:1]([C:9]1[N:13]2[CH2:14][CH2:15][CH:16]([C:17]([OH:19])=[O:18])[C:12]2=[C:11]([Br:20])[CH:10]=1)(=[O:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.Cl.[CH:22](O)([CH3:24])[CH3:23]>>[C:1]([C:9]1[N:13]2[CH2:14][CH2:15][CH:16]([C:17]([O:19][CH:22]([CH3:24])[CH3:23])=[O:18])[C:12]2=[C:11]([Br:20])[CH:10]=1)(=[O:8])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1Participants
4
Procedure
A solution of 1.34 g. of 5-benzoyl-7- bromo-1,2-dihydro- 3H-pyrrolo[1,2-a]pyrrole-1-carboxylic acid in 50 ml. of isopropanol, cooled in an ice bath is saturated with gaseous hydrogen chloride, maintaining the temperature of the reaction mixture below 50° C. The ice bath is then removed and the reaction mixture is stirred for 1.5 hours at room temperature, and evaporated to dryness under reduced pressure; 10 ml. of benzene is added to the residue and the solution is evaporated under vacuum once again, repeating this process a total of three times to completely remove the excess hydrogen chloride, thus obtaining of isopropyl 5-benzoyl-7-bromo-1,2-dihydro-3H-pyrrolo[1,2-a]pyrrole-1-carboxylate. The product is recrystallized from methanol-ethyl acetate.