Pyrazolo[1,5-a]pyridin-2-ylmethanol synthesis

6synthesis methods

Product Name:Pyrazolo[1,5-a]pyridin-2-ylmethanol
CAS Number:76943-47-0
Molecular formula:C8H8N2O
Molecular Weight:148.16

Pyrazolo[1,5-a]pyridine-2-carboxylic acid

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Yield:76943-47-0 77%

Reaction Conditions:

Stage #1: pyrazolo[1,5-a]pyridine-2-carboxylic acidwith dimethylsulfide borane complex in tetrahydrofuran;toluene at 0 - 65; for 5.5 h;Inert atmosphere;
Stage #2: with hydrogenchloride in tetrahydrofuran;water;toluene at 0;Reflux;

Steps:

1.1a 1 a. Synthesis of pyrazolo[1 ,5-a]pyridin-2-ylmethanol

1 a. Synthesis of pyrazolo[1 ,5-a]pyridin-2-ylmethanol To a stirred solution of pyrazolo[1 ,5-a]pyridine-2-carboxylic acid (2.01 g, 12.4 mmol) in 65 ml_ of dry tetrahydrofuran (THF) cooled at 0 ⁵C, under nitrogen, were slowly added 31 ml_ (62.1 mmol) of a 2 M solution of borane dimethyl sulfide in toluene. After 30 min. at room temperature, the solution was heated at 65 ⁵C for 5 h, and then cooled to 0 ⁵C to add 15 mL of water. After addition of 8 ml_ of 6N solution of HCI, the mixture was refluxed for 2 h. Finally, the organic solvent was removed under reduced pressure, 40 mL of methanol were added and concentrated. The residue was solved in ethyl acetate, and washed with aqueous NaOH 10% solution and water. The organic layers were dried (Na₂S0₄) and concentrated to afford 1 .42 g (77%) of pyrazolo[1 ,5-a]pyridin- 2-ylmethanol as a colorless oil.

References:

WO2013/124341,2013,A1 Location in patent:Page/Page column 35-36