Dimethyl methylmalonate → 7-hydroxy-6-methyl-2-phenylpyrazolo[1,5-a]pyrimidin-5(4H)-one

HRID 928251Notes

Reaction equation

[CH3:1][CH:2]([C:7]([O:9]C)=O)[C:3](OC)=[O:4].[NH2:11][C:12]1[NH:16][N:15]=[C:14]([C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[CH:13]=1.C[O-].[Na+]>CO>[OH:9][C:7]1[N:16]2[N:15]=[C:14]([C:17]3[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=3)[CH:13]=[C:12]2[NH:11][C:3](=[O:4])[C:2]=1[CH3:1]

Participants

Conditions

Temperature: 75 °C

Procedure

To a solution of dimethyl methylmalonate (1.30 mL, 9.80 mmol) and 5-amino-3-phenylpyrazole (1.50 g, 9.42 mmol) in methanol (11 mL) is added 25% sodium methoxide in methanol (6.04 mL, 26.4 mmol). The reaction mixture is heated at 75° C. for 48 hr. The precipitate was collected in a Buchner funnel and washed with dichloromethane to provide 7-hydroxy-6-methyl-2-phenylpyrazolo[1,5-a]pyrimidin-5(4H)-one (2.87 g, yield 95%). LCMS: (AA) M+1 242; 1H NMR (400 MHz, DMSO) δ 10.39 (s, 1H), 7.92-7.86 (m, 2H), 7.41-7.33 (m, 2H), 7.32-7.26 (m, 1H), 5.92 (s, 1H), 1.75 (s, 3H).

Workup

customThe precipitate was collected in a Buchner funnel
washwashed with dichloromethane

Sources & evidence

ORD record: ord-d2db23ed4d9e4251b2dd8090b254e53c
Source dataset: uspto-grants-2016_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09290500B2

Reaction notes

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