[F:1][CH2:2][C:3]1([CH2:19][F:20])[CH:8]=[C:7]([C:9]([OH:11])=[O:10])[C:6]2[CH:12]=[C:13]([N+:16]([O-:18])=[O:17])[CH:14]=[CH:15][C:5]=2[O:4]1.S(=O)(=O)(O)O.[CH2:26](O)[CH3:27]>>[CH2:26]([O:10][C:9]([C:7]1[C:6]2[CH:12]=[C:13]([N+:16]([O-:18])=[O:17])[CH:14]=[CH:15][C:5]=2[O:4][C:3]([CH2:2][F:1])([CH2:19][F:20])[CH:8]=1)=[O:11])[CH3:27]A mixture of 41.7 g of 2,2-bis(fluoromethyl)-6-nitro-2H-1-benzopyran-4-carboxylic acid, 20 ml of sulfuric acid and 300 ml of ethyl alcohol was refluxed with heating for 6 hours. The reaction mixture was poured into ice water and crystals separated out were filtered to obtain 42.7 g of 2,2-bis(fluoromethyl)-6-nitro-2H-1-benzopyran-4-carboxylic acid ethyl ester with a melting point of 96°-98° C.
Wird geladen…