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

HRID 1850667Notes

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-d20a804d6b3f4546ba023b12f3525b54
Source dataset: uspto-grants-2015_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08957078B2

Reaction notes

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