Lithium Hydroxide → 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-1H-pyrazole-3-carboxylic acid

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Reaction Steps

The ester (10 g, 19.9 mmoles) obtained from step C was taken in 500 ml 1 neck flask and to it 300 ml of 7:2:1 mixture of THF-methanol-water along with solid lithium hydroxide (2.5 g, 104.6 mol) was added. The mixture was refluxed for 12 hours. The solvents were removed totally and to the residue 200 ml of DCM was added. To that 100 ml of water was added and the mixture was acidified to pH ˜2 using concentrated HCl. The organic layer was separated, washed with 100 ml of brine, dried over sodium sulphate and concentrated to give the acid. This was taken directly to the next step (9.4 g, 100%).

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