Dimethylformamide potassium carbonate → Ethyl 8-chloro-1-cyclopropyl-7-fluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate
Reaction equation
[Cl:1][C:2]1[C:3](F)=[C:4]([CH:18]=[CH:19][C:20]=1[F:21])[C:5]([C:7](=[CH:13][NH:14][CH:15]1[CH2:17][CH2:16]1)[C:8]([O:10][CH2:11][CH3:12])=[O:9])=[O:6].C(=O)([O-])[O-].[K+].[K+].CN(C)C=O>>[Cl:1][C:2]1[C:20]([F:21])=[CH:19][CH:18]=[C:4]2[C:3]=1[N:14]([CH:15]1[CH2:17][CH2:16]1)[CH:13]=[C:7]([C:8]([O:10][CH2:11][CH3:12])=[O:9])[C:5]2=[O:6]Participants
3
Procedure
Reaction of 3-chloro-2,4-difluoro-benzoyl chloride with diethyl malonate gives diethyl (3-chloro-2,4-difluoro-benzoyl)-malonate, and partial hydrolysis and decarboxylation lead to ethyl (3-chloro-2,4-difluoro-benzoyl)-acetate, which is reacted with ethyl orthoformate/acetic anhydride to give ethyl 2-(3-chloro-2,4-difluorobenzoyl)-3-ethoxy-acrylate; further reaction with cyclopropylamine leads to ethyl 2-(3-chloro-2,4-difluoro-benzoyl)-3-cyclopropylaminoacrylate, which is cyclized with potassium carbonate/dimethylformamide to give ethyl 8-chloro-1-cyclopropyl-7-fluoro-1,4-dihydro-4-oxo-3 -quinolinecarboxylate; hydrolysis then finally leads to the corresponding carboxylic acid. The reaction sequence described can be represented by the following equation: ##STR4##