Difluoromethylation of 4,5-dihydro-1-phenyl-3-methyl-1,2,4-triaz

Details Difluoromethylation of 4,5-dihydro-1-phenyl-3-methyl-1,2,4-triaz Difluoromethylation of 4,5-dihydro-1-phenyl-3-methyl-1,2,4-triaz

1997-05-30

1998-05-26

Richter, Johann

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

C07D24912

Patent

active

057567557

ABSTRACT:
An improved process for the difluoromethylation of a 1-(optionally substituted)phenyl-1H-1,2,4-triazol-5-one at the 4-position of the triazole ring with chlorodifluoromethane significantly reduces the cycle time required for the reaction. The improvement comprises reacting the triazolinone with potassium carbonate in a glyme solvent, heating one molar equivalent of a sodium or potassium salt of the triazolinone with 0.1 to 1 molar equivalent of potassium carbonate and 1.5 to 1.8 molar equivalents of chlorodifluoromethane in a glyme solvent, the concentration the triazolinone in the glyme being in the range of 5 to 15 percent weight/volume, at a temperature in the range of 165.degree. to 200.degree. C. for 5 to 30 minutes, with a 10 to 15 percent molar excess of chlorodifluoromethane, either at atmospheric pressure under an inert atmosphere or in a sealed autoclave, and recovering the difluoromethylated triazolinone.

REFERENCES:
patent: 5438149 (1995-08-01), Halfon et al.

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