Aluminium lithium hydride → 4,5,6,7-Tetrahydro-5-(phenylmethyl)-pyrazolo[1,5-a]pyrazine-2-methanol

HRID 1773770Notes

Reaction equation

HRID 1773770 reaction equation
[H-].[Al+3].[Li+].[H-].[H-].[H-].C([O:9][C:10]([C:12]1[CH:28]=[C:15]2[C:16](=O)[N:17]([CH2:20][C:21]3[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=3)[CH2:18][CH2:19][N:14]2[N:13]=1)=O)C>C1COCC1>[C:21]1([CH2:20][N:17]2[CH2:18][CH2:19][N:14]3[N:13]=[C:12]([CH2:10][OH:9])[CH:28]=[C:15]3[CH2:16]2)[CH:22]=[CH:23][CH:24]=[CH:25][CH:26]=1

Participants

4

Reactant 2

HCID 21226445Aluminium lithium hydrideHCID 58465696Ethyl 5-benzyl-4-oxo-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine-2-carboxylate

Product 1

HCID 679602214,5,6,7-Tetrahydro-5-(phenylmethyl)-pyrazolo[1,5-a]pyrazine-2-methanolYield 102%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

A 1M solution of lithium aluminum hydride in THF (6.5 mL, 6.5 mmol) was added dropwise to a stirred solution of 4,5,6,7-tetrahydro-4-oxo-5-(phenylmethyl)-pyrazolo[1,5-a]pyrazine-2-carboxylic acid ethyl ester (0.81 g, 2.7 mmol) in THF (16 mL) under N2 at 0° C. The reaction mixture was stirred at room temperature for 30 minutes, quenched with MeOH and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; 7 M solution of ammonia in methanol in DCM 0/100 to 10/90). The desired fractions were collected and the solvents evaporated in vacuo to yield 4,5,6,7-tetrahydro-5-(phenylmethyl)-pyrazolo[1,5-a]pyrazine-2-methanol (0.67 g, 100% yield) as a colorless oil. C14H17N3O LCMS: Rt 1.25, m/z 244 [M+H]+ (see LCMS Method 1).

Workup

  1. customquenched with MeOH
  2. customthe solvents evaporated in vacuo
  3. customThe crude product was purified by flash column chromatography (silica; 7 M solution of ammonia in methanol in DCM 0/100 to 10/90)
  4. customThe desired fractions were collected
  5. customthe solvents evaporated in vacuo

Sources & evidence

ORD record
ord-c2509b3fca4a4b888d391a0e8a128b32
Source dataset
uspto-grants-2016_02
Patent number
US09255103B2

Reaction notes

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