Sodium borohydride → 2-(2,5-Dimethyl-1H-pyrrol-1-yl)-4-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine

HRID 1412005Notes

Reaction equation

HRID 1412005 reaction equation
[CH3:1][C:2]1[N:3]([C:8]2[CH:17]=[C:11]3[C:12]([CH3:16])=[N:13][CH2:14][CH2:15][N:10]3[N:9]=2)[C:4]([CH3:7])=[CH:5][CH:6]=1.[BH4-].[Na+]>CO>[CH3:7][C:4]1[N:3]([C:8]2[CH:17]=[C:11]3[CH:12]([CH3:16])[NH:13][CH2:14][CH2:15][N:10]3[N:9]=2)[C:2]([CH3:1])=[CH:6][CH:5]=1

Participants

4

Reactant 2

HCID 4311764Sodium borohydrideHCID 866845252-(2,5-Dimethyl-1H-pyrrol-1-yl)-4-methyl-6,7-dihydropyrazolo[1,5-a]pyrazine

Product 1

HCID 866845262-(2,5-Dimethyl-1H-pyrrol-1-yl)-4-methyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazineYield 43%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer was charged with 287f (3.56 g, 1.0 eq., 15.6 mmol), NaBH4 (2.96 g, 5.0 eq., 78.0 mmol), and methanol (50 mL). The mixture was stirred at room temperature for 1 h and concentrated under reduced pressure. The residue was partitioned between water (50 mL) and dichloromethane (50 mL). The water phase was extracted with dichloromethane (3×50 mL). The combined organic layer was concentrated under reduced pressure. The residue was purified by silica-gel column chromatography eluting with 10:1 dichloromethane/methanol to afford 287g as a colorless oil (1.54 g, 43% over two steps). MS-ESI: [M+H]+ 231.3. 1H NMR (500 MHz, CDCl3) δ 5.91 (s, 1H), 5.86 (s, 2H), 4.17-4.11 (m, 3H), 3.51-3.48 (m, 1H), 3.36-3.31 (m, 1H), 2.13 (s, 6H), 1.50 (d, J=6.5 Hz, 3H).

Workup

  1. customA 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer
  2. concentrationconcentrated under reduced pressure
  3. customThe residue was partitioned between water (50 mL) and dichloromethane (50 mL)
  4. extractionThe water phase was extracted with dichloromethane (3×50 mL)
  5. concentrationThe combined organic layer was concentrated under reduced pressure
  6. customThe residue was purified by silica-gel column chromatography
  7. washeluting with 10:1 dichloromethane/methanol

Sources & evidence

ORD record
ord-8001de65769d4adb92037a0d33cf5975
Source dataset
uspto-grants-2014_12
Patent number
US08921353B2

Reaction notes

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