Dichloromethane → 1-(2-Nitro-6,7-dihydropyrazolo[1,5-a]pyrazin-5(4H)-yl)ethanone

A 200 mL round bottom flask was charged with 2-nitro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine 108a (2.1 g, 12.9 mmol), triethylamine (5.5 mL, 38.7 mmol), acetyl chloride (1.1 mL, 15.5 mmol) and CH2Cl2 (100 mL). The mixture stirred at room temperature over night. After this time, the reaction mixture was concentrated under reduced pressure, and to the residue was added H2O (50 mL) and EtOAc (50 mL). The aqueous layer was separated and extracted with EtOAc (2×50 mL). The combined organic extracts were washed with brine (100 mL). The combined aqueous extracts were back extracted with 9:1 CH2Cl2:MeOH (2×50 mL). The combined organics were dried over sodium sulfate. The resulting residue was purified by column chromatography eluting with a gradient of CH2Cl2-9:1 CH2Cl2:MeOH to afford a 84% yield (2.3 g) of 1-(2-nitro-6,7-dihydropyrazolo[1,5-a]pyrazin-5(4H)-yl)ethanone 108b.

1. concentrationAfter this time, the reaction mixture was concentrated under reduced pressure
2. additionto the residue was added H2O (50 mL) and EtOAc (50 mL)
3. customThe aqueous layer was separated
4. extractionextracted with EtOAc (2×50 mL)
5. washThe combined organic extracts were washed with brine (100 mL)
6. extractionThe combined aqueous extracts were back extracted with 9:1 CH2Cl2
7. dry with materialThe combined organics were dried over sodium sulfate
8. customThe resulting residue was purified by column chromatography
9. washeluting with a gradient of CH2Cl2-9:1 CH2Cl2

ORD record

ord-d662d9fc1efa415ca52eb3a2f0e1ed01

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08618107B2