4-Amino-1-methyl-3-propyl-1H-pyrazole-5-carboxamide → Sildenafil

HRID 1831473Notes

Reaction equation

[CH2:1]([O:3][C:4]1[CH:9]=[CH:8][C:7]([S:10]([N:13]2[CH2:18][CH2:17][N:16]([CH3:19])[CH2:15][CH2:14]2)(=[O:12])=[O:11])=[CH:6][C:5]=1[CH:20]=O)[CH3:2].[NH2:22][C:23]1[C:24]([CH2:32][CH2:33][CH3:34])=[N:25][N:26]([CH3:31])[C:27]=1[C:28]([NH2:30])=[O:29]>[Pd].C1(C)C(C)=CC=CC=1>[CH2:1]([O:3][C:4]1[CH:9]=[CH:8][C:7]([S:10]([N:13]2[CH2:14][CH2:15][N:16]([CH3:19])[CH2:17][CH2:18]2)(=[O:12])=[O:11])=[CH:6][C:5]=1[C:20]1[NH:30][C:28](=[O:29])[C:27]2[N:26]([CH3:31])[N:25]=[C:24]([CH2:32][CH2:33][CH3:34])[C:23]=2[N:22]=1)[CH3:2]

Participants

Conditions

Temperature: 200 °C

Procedure

A solution of xylene (60 mL) containing 1-(4-ethoxy-3-formylphenylsulfonyl)-4-methylpiperazine (4.0 g, 0.013 mol, prepared analogously to the methods described in DE 24 44 720) and 4-amino-1-methyl-3-propyl-1H-pyrazole-5-carboxamide (Example 37 of EP 0463756) (2.6 g, 0.014 mol) was submitted to 46 hours at 200° C. and 34.5 kPa (5 psi). The reaction was allowed to cool and the catalyst (10% Pd/C, 3.1 g, 50% w/w) was added. The reaction was heated at 200° C. under 34.5 kPa (5 psi) of pressure for a further 12 hours. The catalyst was recovered by filtration and the organic solvent removed in vacuo to give 4.2 g of crude product, which was purified by trituration in methyl ethyl ketone (MEK). This yielded 3.3 g (53%) of the title compound as an off-white solid.

Workup

customprepared analogously to the methods
temperatureto cool
filtrationThe catalyst was recovered by filtration
customthe organic solvent removed in vacuo

Sources & evidence

ORD record: ord-464ecb03e41646ab9da60d2d07e2e81d
Source dataset: uspto-grants-2006_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07067660B2

Reaction notes

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