Chlorosulfonic acid → Demethylpiperazinyl Desethyl Sildenafil Sulfonyl Chloride

HRID 2226136Notes

Reaction equation

HRID 2226136 reaction equation
[OH:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[C:8]1[NH:9][C:10](=[O:21])[C:11]2[N:16]([CH3:17])[N:15]=[C:14]([CH2:18][CH2:19][CH3:20])[C:12]=2[N:13]=1.[Cl:22][S:23](O)(=[O:25])=[O:24]>>[Cl:22][S:23]([C:5]1[CH:6]=[CH:7][C:2]([OH:1])=[C:3]([C:8]2[NH:9][C:10](=[O:21])[C:11]3[N:16]([CH3:17])[N:15]=[C:14]([CH2:18][CH2:19][CH3:20])[C:12]=3[N:13]=2)[CH:4]=1)(=[O:25])=[O:24]

Participants

3

Reactant 2

HCID 24638Chlorosulfonic acidHCID 1355465171,6-Dihydro-5-(2-hydroxyphenyl)-1-methyl-3-propyl-7H-pyrazolo[4,3-d]pyrimidin-7-one

Product 1

HCID 135738545Demethylpiperazinyl Desethyl Sildenafil Sulfonyl ChlorideYield 75%

Conditions

Temperature
0 °C

Procedure

5-(2-Hydroxyphenyl)-1-methyl-3-n-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidin-7-one (0.239 g, 0.00084 mol) was added, in portions, to stirred chlorosulphonic acid (3 ml) cooled to 0° C. under a nitrogen atmosphere, and the resulting deep red solution stirred at room temperature for 18 hours. The reaction mixture was then added dropwise, with care, to stirred ice/water to give a brown solid. The latter mixture was extracted with dichloromethane (3×30 ml), the combined extracts dried (Na2SO4) and filtered, and the filtrate evaporated under vacuum to give a brown solid (0.24 g, 75%), used in the next step without further purification; Rf 0.3 (silica; dichloromethane, methanol; 95:5).

Workup

  1. additionThe reaction mixture was then added dropwise, with care
  2. customto give a brown solid
  3. extractionThe latter mixture was extracted with dichloromethane (3×30 ml)
  4. dry with materialthe combined extracts dried (Na2SO4)
  5. filtrationfiltered
  6. customthe filtrate evaporated under vacuum

Sources & evidence

ORD record
ord-1befbb53fbdc4c9ca8d9a0c4e25710e4
Source dataset
uspto-grants-1994_09
Patent number
US05346901

Reaction notes

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