Acetic Acid → ethyl 5-(4-chlorophenylsulfonyl)-4,5-dihydro-1H-pyrazolo[4,3-c]pyridine-4-carboxylate

HRID 15742Notes

Reaction equation

HRID 15742 reaction equation
[Cl:1][C:2]1[CH:7]=[CH:6][C:5]([S:8]([N:11]2[CH:16]=[CH:15][C:14](=O)[C:13](=[CH:18][N:19](C)C)[CH:12]2[C:22]([O:24][CH2:25][CH3:26])=[O:23])(=[O:10])=[O:9])=[CH:4][CH:3]=1.C(O)(=O)C.O.[NH2:32]N>CCO>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]([S:8]([N:11]2[CH:16]=[CH:15][C:14]3[NH:32][N:19]=[CH:18][C:13]=3[CH:12]2[C:22]([O:24][CH2:25][CH3:26])=[O:23])(=[O:10])=[O:9])=[CH:6][CH:7]=1

Participants

5

Reactant 3

HCID 176Acetic AcidHCID 24654Hydrazine hydrate (1:1)HCID 68502343Ethyl 1-(4-chlorophenylsulfonyl)-3-((dimethylamino)methylene)-4-oxo-1,2,3,4-tetrahydropyridine-2-carboxylate

Product 1

HCID 59342407ethyl 5-(4-chlorophenylsulfonyl)-4,5-dihydro-1H-pyrazolo[4,3-c]pyridine-4-carboxylateYield 30.4%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A flask was charged with compound 104 (5.8 g, 14.6 mmol), acetic acid (10 mL) and EtOH (10 mL). Hydrazine hydrate (1.4 mL, 30 mmol) was added and the reaction stirred at room temperature for 2 hours. The reaction mixture was concentrated in vacuo and the residue was taken up in EtOAc. The organic layer was washed with sat. aq. NaHCO3, brine, dried over Na2SO4, filtered, and concentrated in vacuo to yield crude material that was purified by flash chromatography (50% EtOAc/hexanes) to yield 1.63 g (30%) of compound 105 as a yellow foam. 1H NMR (CDCl3) δ 7.76 (d, J=6.3 Hz, 2H), 7.48-7.41 (m, 3H), 6.90-6.87 (m, 1H), 5.96-5.93 (m, 1H), 5.80 (s, 1H), 4.13-4.11 (m, 2H), 1.24-1.18 (m, 3H; MS (m/z) 368.0 (M+H)+.

Workup

  1. concentrationThe reaction mixture was concentrated in vacuo
  2. washThe organic layer was washed with sat. aq. NaHCO3, brine
  3. dry with materialdried over Na2SO4
  4. filtrationfiltered
  5. concentrationconcentrated in vacuo
  6. customto yield crude material that
  7. customwas purified by flash chromatography (50% EtOAc/hexanes)

Sources & evidence

ORD record
ord-23990e764170470189064d7f252ac0e5
Source dataset
uspto-grants-2010_06
Patent number
US07732609B2

Reaction notes

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