Dimethyl Sulfoxide → 5-(3-Methoxypropyl)-2-nitro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazine

HRID 593113Notes

Reaction equation

Br[CH2:2][CH2:3][N:4]1[C:8]([CH2:9]Cl)=[CH:7][C:6]([N+:11]([O-:13])=[O:12])=[N:5]1.[CH3:14][O:15][CH2:16][CH2:17][CH2:18][NH2:19].CS(C)=O>C(OCC)(=O)C>[CH3:14][O:15][CH2:16][CH2:17][CH2:18][N:19]1[CH2:2][CH2:3][N:4]2[N:5]=[C:6]([N+:11]([O-:13])=[O:12])[CH:7]=[C:8]2[CH2:9]1

Participants

Conditions

Temperature: 120 °C

Procedure

A microwave vial equipped with a magnetic stirrer was charged with 1-(2-bromoethyl)-5-(chloromethyl)-3-nitro-1H-pyrazole 296c (600 mg, 2.2 mmol), 3-methoxypropan-1-amine (595 mg, 6.6 mmol), and DMSO (6 mL). It was heated at 120° C. under microwave irradiation for 0.5 h. The mixture was then cooled to room temperature and diluted with ethyl acetate (30 mL). The resulting mixture was washed with water (3×10 ml). The organic layer was dried and filtered. The filtrate was concentrated under pressure and the residue was purified by silica-gel column chromatography eluting with 30:1 dichloromethane/methanol to afford 309a (350 mg, 66%) as a yellow solid. MS-ESI: [M+H]+ 241.1

Workup

customA microwave vial equipped with a magnetic stirrer
temperatureThe mixture was then cooled to room temperature
washThe resulting mixture was washed with water (3×10 ml)
customThe organic layer was dried
filtrationfiltered
concentrationThe filtrate was concentrated under pressure
customthe residue was purified by silica-gel column chromatography
washeluting with 30:1 dichloromethane/methanol

Sources & evidence

ORD record: ord-5cb7072882d64911902de754bc7488c9
Source dataset: uspto-grants-2016_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09238655B2

Reaction notes

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