Aluminium lithium hydride → 7-bromo-4-(2-hydroxyethyl)-3,4-dihydropyrrolo[1,2-a]pyrazin-1(2H)-one

Temperature

0 °C

Ethyl 2-(7-bromo-1-oxo-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazin-4-yl)acetate (1.23 g, 4.1 mmol) was treated with THF (30 mL), cooled to 0° C. and treated with LiAlH4, 1.0 M solution in THF (4.1 mL, 4.1 mmol) and stirred at 0° C. for 30 min. The reaction was quenched by slow dropwise addition of an aq. solution of sodium potassium tartrate and stirred at RT for 30 min. The resulting mixture was extracted with EtOAc (3×25 mL), washed with brine and dried over MgSO4, filtered and concentrated in vacuo to afford crude 7-bromo-4-(2-hydroxyethyl)-3,4-dihydropyrrolo[1,2-a]pyrazin-1(2H)-one (987 mg, 3.81 mmol, 93% yield) as a white crystalline solid: 1H NMR (400 MHz, MeOH-d4) δ ppm 7.10 (1H, s), 6.83 (1H, s), 4.47 (1H, tt, J=7.1, 3.7 Hz), 3.85 (1H, dd, J=13.2, 4.2 Hz), 3.68 (1H, dt, J=11.2, 5.6 Hz), 3.46-3.56 (2H, m), 1.91-2.07 (2H, m). m/z (ESI, +ve ion) 259.0/261.0 (M+H)+.

1. customThe reaction was quenched by slow dropwise addition of an aq. solution of sodium potassium tartrate
2. stirringstirred at RT for 30 min
3. extractionThe resulting mixture was extracted with EtOAc (3×25 mL)
4. washwashed with brine
5. dry with materialdried over MgSO4
6. filtrationfiltered
7. concentrationconcentrated in vacuo

ORD record

ord-05ab2590dc7343eb862d4321ee37ed04

Source dataset

uspto-grants-2016_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09394297B2