Phosphorus oxychloride → methyl 3-chloro-1-methyl-4,5-dihydro-1H-pyrazole-5-carboxylate

HRID 402484Notes

Reaction equation

HRID 402484 reaction equation
O=P(Cl)(Cl)[Cl:3].O[C:7]1[CH2:11][CH:10]([C:12]([O:14][CH3:15])=[O:13])[N:9]([CH3:16])[N:8]=1>C(Cl)(Cl)Cl>[Cl:3][C:7]1[CH2:11][CH:10]([C:12]([O:14][CH3:15])=[O:13])[N:9]([CH3:16])[N:8]=1

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 178498599HCID 178498599, compound

Product 1

HCID 67209560methyl 3-chloro-1-methyl-4,5-dihydro-1H-pyrazole-5-carboxylateYield 52.2%

Reagents, catalysts & solvents 1

HCID 6212ChloroformSolvent2×

Procedure

To a solution of POCl3 (31.8 ml, 341 mmol) and Net3 (47.6 ml, 341 mmol) in CHCl3 (100 ml) at −5° C. was added a solution of methyl 3-hydroxy-1-methyl-4,5-dihydro-1H-pyrazole-5-carboxylate (36 g, 228 mmol) in CHCl3 (100 ml). After 1 h at this temperature, the mixture was stirred for another 20 h under warming to rt. Then, the reaction mixture was poured on ice water and extracted with CHCl3. The combined organics were washed with water, dried over Na2SO4 and evaporated under reduced pressure. This yielded the title compound (21 g, 52%) which was used in the next step without further purification. [LCMS RtJ=0.63 min; [M+H]+=177.0, 179.0]

Workup

  1. additionThen, the reaction mixture was poured on ice water
  2. extractionextracted with CHCl3
  3. washThe combined organics were washed with water
  4. dry with materialdried over Na2SO4
  5. customevaporated under reduced pressure

Sources & evidence

ORD record
ord-d744a7b091ec495990d10dac49ef6102
Source dataset
uspto-grants-2014_06
Patent number
US08742106B2

Reaction notes

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