Hydrofluoric Acid → 1-(2,2-Dimethyl-3,3-difluoro-indan-1-yl)-5-imidazolecarboxylic acid methyl ester
Reaction equation
[CH3:1][O:2][C:3]([C:5]1[N:9]([CH:10]2[C:18]3[C:13](=[CH:14][CH:15]=[CH:16][CH:17]=3)[C:12](=O)[C:11]2([CH3:21])[CH3:20])[CH:8]=[N:7][CH:6]=1)=[O:4].S(F)(F)(F)[F:23].[FH:27]>>[CH3:1][O:2][C:3]([C:5]1[N:9]([CH:10]2[C:18]3[C:13](=[CH:14][CH:15]=[CH:16][CH:17]=3)[C:12]([F:23])([F:27])[C:11]2([CH3:21])[CH3:20])[CH:8]=[N:7][CH:6]=1)=[O:4]Participants
4
Procedure
A mixture of 11.4 g of 1-(2,2-dimethyl-3-oxo-indan-1-yl)-5-imidazolecarboxylic acid methyl ester, 43 g of sulfur tetrafluoride and 160 g of hydrogen fluoride is heated for 24 hours to +50° C. in an acid-resistant autoclave. The pressure is about 7 bars. The unreacted hydrogen fluoride is removed and the residue is taken up with methylene chloride. The organic phase is neutralized with sodium bicarbonate, washed with water, dried with sodium sulfate and concentrated to dryness. Chromatography of the residue at a silica gel column with a diethyl ether/hexane mixture (3:1 by volume) affords 8.4 g of 1-(2,2-dimethyl-3,3-difluoro-indan-1-yl)-5-imidazolecarboxylic acid methyl ester, mp. 96°-97° C.