Sodium borohydride → 5-cyclopropylmethyl-2-hydroxymethyl-6,7-dihydro-5H-pyrazolo[1,5-a]pyrazin-4-one

HRID 2046206Notes

Reaction equation

[BH4-].[Na+].C([O:5][C:6]([C:8]1[CH:21]=[C:11]2[C:12](=[O:20])[N:13]([CH2:16][CH:17]3[CH2:19][CH2:18]3)[CH2:14][CH2:15][N:10]2[N:9]=1)=O)C>C1COCC1.CO.O>[CH:17]1([CH2:16][N:13]2[CH2:14][CH2:15][N:10]3[N:9]=[C:8]([CH2:6][OH:5])[CH:21]=[C:11]3[C:12]2=[O:20])[CH2:18][CH2:19]1

Participants

Conditions

Temperature: 80 °C

Procedure

Sodium borohydride (0.23 mL, 6.1 mmol) was added dropwise to a stirred solution of 5-cyclopropylmethyl-4-oxo-4,5,6,7-tetrahydro-pyrazolo[1,5-a]pyrazine-2-carboxylic acid ethyl ester (0.32 g, 1.2 mmol) in a mixture of THF (4 mL) and MeOH (1 mL) under N2 at 0° C. The reaction mixture was stirred at 80° C. for 30 minutes and then diluted with water and extracted with DCM. The aqueous layer was acidified with a 1N solution of HCl and extracted with DCM. The organic layers were combined, dried (NaSO4), filtered 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 5-cyclopropylmethyl-2-hydroxymethyl-6,7-dihydro-5H-pyrazolo[1,5-a]pyrazin-4-one (0.21 g, 78% yield) as a colorless oil.

Workup

extractionextracted with DCM
extractionextracted with DCM
dry with materialdried (NaSO4)
filtrationfiltered
customthe solvents evaporated in vacuo
customThe crude product was purified by flash column chromatography (silica; 7 M solution of ammonia in methanol in DCM 0/100 to 10/90)
customThe desired fractions were collected
customthe solvents evaporated in vacuo

Sources & evidence

ORD record: ord-4cd71b07eb954e31a64e74fc44f40a95
Source dataset: uspto-grants-2013_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08592422B2

Reaction notes

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