تفاعل #702863

معادلة التفاعل

HCl

cysteine hydrochloride

benzoyl chloride

potassium hydroxide

→

N,S-dibenzoylcysteine

المردود 81.0%

المذيبات

water

water

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةwhile cooling at 0°-5° C
2. 2
   workup.WAITwas continued for a further hour at room temperature
3. 3
   ترشيحthe precipitate was filtered off under suction
4. 4
   غسيلwashed neutral with water
5. 5
   أخرىthe product was recrystallized twice from methanol/water

الإجراء التجريبي

63.0 g (0.4 mole) of cysteine hydrochloride were suspended in 400 ml of water, and 112.5 g (0.8 mole) of benzoyl chloride were added. A solution of 89.8 g (1.6 moles) of potassium hydroxide in 1 liter of water was added dropwise to the stirred mixture, while cooling at 0°-5° C. Stirring was continued for a further hour at room temperature, after which the mixture was rendered strongly acidic with aqueous 2N HCl, the precipitate was filtered off under suction and washed neutral with water, and the product was recrystallized twice from methanol/water. 106.3 g (81%) of N,S-dibenzoylcysteine of melting point 183°-185° C. were obtained; Rf=0.43 in system I, [α]D20 =-85.7° (c=1 in absolute ethanol).

المصدر