2-methylprop-1-ene-1-sulfonyl chloride

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 479 mg (3.0 mmol) of 2-methylpropene-1-sulfonyl chloride are added to a solution of 800 mg (2.8 mmol) of methyl (S)-3-tert-butoxycarbonylamino-2-piperazin-1-ylpropanoate (prepared as described in example 23.1) and 775 μl (5.5 mmol) of triethylamine in 8 ml of dichloromethane, cooled beforehand to 0° C. The reaction medium is stirred at ambient temperature for 18 h and then water is added and the medium is extracted with dichloromethane. The organic phase is washed with water, dried over magnesium sulfate, filtered and concentrated. The residue obtained Is purified by chromatography on silica gel, elution being carried out with a 5/5 heptane/ethyl acetate mixture. 785 mg (71%) of methyl (S)-3-tert-butoxycarbonylamino-2-[4-(2-methylpropane-1-sulfonyl)piperazin-1-yl]propanoate are obtained in the form of a colorless oil. the medium is extracted with dichloromethane The organic phase is washed with water dried over magnesium sulfate filtered concentrated The residue obtained Is purified by chromatography on silica gel, elution

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 479 mg (3.0 mmol) of 2-methylpropene-1-sulfonyl chloride are added to a solution of 800 mg (2.8 mmol) of methyl (S)-3-tert-butoxycarbonylamino-2-piperazin-1-ylpropanoate (prepared as described in example 23.1) and 775 μl (5.5 mmol) of triethylamine in 8 ml of dichloromethane, cooled beforehand to 0° C. The reaction medium is stirred at ambient temperature for 18 h and then water is added and the medium is extracted with dichloromethane. The organic phase is washed with water, dried over magnesium sulfate, filtered and concentrated. The residue obtained Is purified by chromatography on silica gel, elution being carried out with a 5/5 heptane/ethyl acetate mixture. 785 mg (71%) of methyl (S)-3-tert-butoxycarbonylamino-2-[4-(2-methylpropane-1-sulfonyl)piperazin-1-yl]propanoate are obtained in the form of a colorless oil. the medium is extracted with dichloromethane The organic phase is washed with water dried over magnesium sulfate filtered concentrated The residue obtained Is purified by chromatography on silica gel, elution

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 479 mg (3.0 mmol) of 2-methylpropene-1-sulfonyl chloride are added to a solution of 800 mg (2.8 mmol) of methyl (S)-3-tert-butoxycarbonylamino-2-piperazin-1-ylpropanoate (prepared as described in example 23.1) and 775 μl (5.5 mmol) of triethylamine in 8 ml of dichloromethane, cooled beforehand to 0° C. The reaction medium is stirred at ambient temperature for 18 h and then water is added and the medium is extracted with dichloromethane. The organic phase is washed with water, dried over magnesium sulfate, filtered and concentrated. The residue obtained Is purified by chromatography on silica gel, elution being carried out with a 5/5 heptane/ethyl acetate mixture. 785 mg (71%) of methyl (S)-3-tert-butoxycarbonylamino-2-[4-(2-methylpropane-1-sulfonyl)piperazin-1-yl]propanoate are obtained in the form of a colorless oil. the medium is extracted with dichloromethane The organic phase is washed with water dried over magnesium sulfate filtered concentrated The residue obtained Is purified by chromatography on silica gel, elution