3-(Acetylsulfanyl)propanoyl chloride → (+/-)-1-[3-(Acetylthio)-1-oxopropyl]-4,5-dihydro-3-(2-thienyl)-1H-pyrazole-5-carboxylic acid
Reaction equation
[S:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[C:6]1[CH2:10][CH:9]([C:11]([OH:13])=[O:12])[NH:8][N:7]=1.[C:14]([S:17][CH2:18][CH2:19][C:20](Cl)=[O:21])(=[O:16])[CH3:15]>C([O-])([O-])=O.[Na+].[Na+]>[C:14]([S:17][CH2:18][CH2:19][C:20]([N:8]1[CH:9]([C:11]([OH:13])=[O:12])[CH2:10][C:6]([C:2]2[S:1][CH:5]=[CH:4][CH:3]=2)=[N:7]1)=[O:21])(=[O:16])[CH3:15]Participants
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
(±)-4,5-Dihydro-3-(2-thienyl)-1H-pyrazole-5-carboxylic acid is dissolved in aqueous Na2CO3 (1.38 g) at pH 8.6. The temperature is lowered to 5° C. and 3-(acetylthio)propionyl chloride (4.15 g) and a 25% solution of Na2CO3 are added simultaneously maintaining the pH at 8-9. The final pH is 8.9 and the reaction is stirred for 2 hours at room temperature. It is then extracted with ethyl acetate and the ethyl acetate is discarded. The aqueous layer is made strongly acid with 20% HCl and the gummy precipitate is extracted with ethyl acetate. The ethyl acetate is dried over MgSO4 and removed to yield a viscous residue (7.2 g) which is triturated with ether to yield 5.1 g of material, melting point 127°-130° C., dec. After recrystallization from CH3CN (very soluble) the melting point is constant at 134°-136° C., dec.
Workup
- customis lowered to 5° C.
- temperaturemaintaining the pH at 8-9
- extractionIt is then extracted with ethyl acetate
- extractionthe gummy precipitate is extracted with ethyl acetate
- dry with materialThe ethyl acetate is dried over MgSO4
- customremoved
Sources & evidence
- ORD record
- ord-c39a2cfc81064a9c938bf2e9677cf4f5
- Source dataset
- uspto-grants-1981_03
- Patent number
- US04254267
Reaction notes
Loading…