Reaction #48039

Reaction equation

N-[(4-chlorophenyl)sulfonyl]-1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxamide

PCl5

HCl

DIPEA

→

N-[(4-chlorophenyl)sulfonyl]-N′-methyl-1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxamidine

Yield 15.0%

Solvents

methylamine

chlorobenzene

dichloromethane

Conditions

Workup

1. 1
   TemperatureAfter cooling the mixture to room temperature the residue
2. 2
   workup.STIRRINGThe resulting mixture is stirred for 16 hours at room temperature
3. 3
   Washtwice washed with water
4. 4
   Dryingdried over MgSO4
5. 5
   Filtrationfiltered
6. 6
   Concentrationconcentrated in vacuo
7. 7
   OtherThe resulting residue is further purified by flash chromatography (silica gel, dichloromethane/acetone=99/1 (v/v/),
8. 8
   Otherfollowed by crystallization from diisopropyl ether

Procedure

Part B: A stirred mixture of N-[(4-chlorophenyl)sulfonyl]-1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxamide (2.36 gram, 5 mmol), PCl5 (1.15 g, 5.5 mmol) and chlorobenzene (50 ml) is heated for 90 minutes at 140° C. After cooling the mixture to room temperature the residue is dissolved in dichloromethane and methylamine.HCl (0.34 g, 5 mmol) and DIPEA (1.74 ml, 10 mmol) are successively added. The resulting mixture is stirred for 16 hours at room temperature, twice washed with water, dried over MgSO4, filtered and concentrated in vacuo. The resulting residue is further purified by flash chromatography (silica gel, dichloromethane/acetone=99/1 (v/v/), followed by crystallization from diisopropyl ether to give N-[(4-chlorophenyl)sulfonyl]-N′-methyl-1-(4-chlorophenyl)-5-phenyl-4,5-dihydro-(1H)-pyrazole-3-carboxamidine (0.36 gram, 15% yield). Melting point: 134-144° C. Rf (silica gel, diethyl ether=0.4).

Source