Hydrogen Bromide → 1H-Pyrazole-5-carboxylic acid, 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-, ethyl ester

HRID 2057110Notes

Reaction equation

HRID 2057110 reaction equation
[Cl:1][C:2]1[C:3]([N:8]2[CH:12]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[CH2:11][C:10](OS(C3C=CC=CC=3)(=O)=O)=[N:9]2)=[N:4][CH:5]=[CH:6][CH:7]=1.[BrH:28].C(=O)([O-])O.[Na+]>C(O)(=O)C>[Br:28][C:10]1[CH2:11][CH:12]([C:13]([O:15][CH2:16][CH3:17])=[O:14])[N:8]([C:3]2[C:2]([Cl:1])=[CH:7][CH:6]=[CH:5][N:4]=2)[N:9]=1

Participants

5

Reactant 3

HCID 260Hydrogen BromideHCID 516892Sodium BicarbonateHCID 866008331H-Pyrazole-5-carboxylic acid, 1-(3-chloro-2-pyridinyl)-4,5-dihydro-3-[(phenylsulfonyl)oxy]-, ethyl ester2×

Product 1

HCID 100653831H-Pyrazole-5-carboxylic acid, 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-, ethyl esterYield 85%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent2×

Procedure

A solution of ethyl 1-(3-chloro-2-pyridinyl)-4,5-dihydro-3-[(phenylsulfonyl)oxy]-1H-pyrazole-5-carboxylate (i.e. the product of Step A)(1.0 g, 2.44 mmol) in acetic acid (4 mL) was added to a solution of hydrogen bromide in acetic acid (33%, 1.2 g, 4.89 mmol). After about 1 h the reaction mixture was added to saturated aqueous sodium hydrogen carbonate solution (100 mL). The mixture was then extracted with ethyl acetate (2×50 mL), and the combined extracts were dried (MgSO4) and evaporated to provide the title product as an oil (0.69 g, 85% yield), which slowly crystallized. The 1H NMR spectrum was the same as reported for the product of Example 1, Step C.

Workup

  1. extractionThe mixture was then extracted with ethyl acetate (2×50 mL)
  2. dry with materialthe combined extracts were dried (MgSO4)
  3. customevaporated

Sources & evidence

ORD record
ord-0055b39401d643d1b1f31c7520dcee3e
Source dataset
uspto-grants-2008_02
Patent number
US07335780B2

Reaction notes

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