Water → Allyl 2-amino-6-fluoro-pyrazolo[1,5-a]pyrimidine-3-carboxylate

HRID 524838Notes

Reaction equation

[NH2:1][C:2]1[C:6]([C:7]([O:9][CH2:10][CH:11]=[CH2:12])=[O:8])=[C:5]([NH2:13])[NH:4][N:3]=1.O.C(N(C(C)C)[CH:19]=[C:20]([F:23])[CH:21]=O)(C)C>CS(C)=O>[NH2:13][C:5]1[C:6]([C:7]([O:9][CH2:10][CH:11]=[CH2:12])=[O:8])=[C:2]2[N:1]=[CH:19][C:20]([F:23])=[CH:21][N:3]2[N:4]=1

Participants

Conditions

Temperature: 100 °C

Procedure

To a suspension of allyl 3,5-diamino-1H-pyrazole-4-carboxylate 3 (42.72 g, 234.5 mmol) in DMSO (270.8 mL)/Water (270.8 mL), was added p-TsOH hydrate (46.72 g, 245.6 mmol) and 3-(diisopropylamino)-2-fluoro-prop-2-enal (described in Tetrahedron Letters, 33(3), 357-60; 1992) (38.69 g, 223.3 mmol). The reaction mixture was heated to 100° C. for 3 h during which time a solid slowly precipitated out of solution. The orange suspension was allowed to cool down to RT overnight. The solid was filtered, washed with water and dried under vacuum to give allyl 2-amino-6-fluoro-pyrazolo[1,5-a]pyrimidine-3-carboxylate 4a as a sand solid (45.05 g, 85% yield).

Workup

customslowly precipitated out of solution
temperatureto cool down to RT overnight
filtrationThe solid was filtered
washwashed with water
customdried under vacuum

Sources & evidence

ORD record: ord-507f90463dac42178a4e7d1c26c38263
Source dataset: uspto-grants-2016_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09340546B2

Reaction notes

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