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

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).

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

ORD 기록

ord-24728a1111bc4deeb900b2179b0228fa

출처 데이터셋

uspto-grants-2016_01

DOI

10.6084/m9.figshare.5104873.v1

특허 번호

US09238655B2