Carbon Dioxide → 4-((2-Fluoroethyl)(methyl)carbamoyl)-1-methyl-1H-pyrazole-5-carboxylic acid

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Reaction Conditions

Reaction Steps

In a 50 mL three-necked flask, N-(2-fluoroethyl)-N,1-dimethyl-1H-pyrazole-4-carboxamide (500 mg, 2.7 mmol) was combined with THF (10.0 ml) to give a colorless solution. 1,1,4,7,7-Pentamethyldiethylenetriamine (621 μl, 2.97 mmol) was added, and, after cooling down to −100° C., tBuLi (1.6 M in pentane, 2.53 ml, 4.05 mmol) was added dropwise. After stirring 30 min an excess of dry ice was carefully added. After 5 min, the cooling bath was removed and the mixture was allowed to warm up to RT. H2O was added and un-reacted starting material was removed by extraction with CH2Cl2. The aqueous layer was then acidified using 1 N HCl solution, and the acid was extracted using CH2Cl2. After drying over Na2SO4, filtration and concentration in vacuum, the viscous oil was dried in HV to yield 307 mg (50%) of product as a light brown viscous oil. MS: m/z=230.2 [M+H]+.

Provenance & Evidence