Dichloromethane → 3-Nitro-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine

HRID 1768876Notes

Reaction equation

[NH2:1][C:2]1[C:6]([N+:7]([O-:9])=[O:8])=[CH:5][NH:4][N:3]=1.[H-].[Na+].Br[CH2:13][CH2:14][CH2:15]Br.ClCCl>CN(C=O)C>[N+:7]([C:6]1[CH:5]=[N:4][N:3]2[CH2:15][CH2:14][CH2:13][NH:1][C:2]=12)([O-:9])=[O:8]

Participants

Conditions

Temperature: 0 °C

Procedure

A solution of 51.2 g (0.4 moles) 3-amino-4-nitropyrazole in 650 ml dried DMF is slowly added by drops to a suspension of 10 g (0.4 moles) sodium hydride in 200 ml dried DMF. After the reaction is concluded, 121 g (0.6 moles) 1,3-dibromopropane in 250 ml DMF are added. The mixture is then heated for 5 hours accompanied by reflux. After cooling, the preparation is reduced to dryness. When the residue is treated with 300 ml dichloromethane and subsequently cooled to 0° C. the product is precipitated out together with NaBr. The raw product is recrystallized from 1200 ml ethanol. 59 g (38%) ocher-colored crystals with a melting point of 251°-252° C. are obtained.

Workup

temperatureThe mixture is then heated for 5 hours
temperatureby reflux
temperatureAfter cooling
customis precipitated out together with NaBr
customThe raw product is recrystallized from 1200 ml ethanol

Sources & evidence

ORD record: ord-b6dca452f357446580ea6c1bab1d7757
Source dataset: uspto-grants-1995_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05380340

Reaction notes

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