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50 g (0.129 mmol) of cholesterol are dissolved in 250 ml of pyridine and cooled to about 5° C. with ice/water. Under argon, 49 g (0.258 mol) of tosyl chloride are added in portions thereto. When the addition is complete, the mixture is stirred for a further 15 minutes with cooling. The ice-bath is then removed and the mixture is stirred for 2 days at room temperature to complete the reaction. The resulting fine suspension is poured onto 1.2 liters of ice-water and stirred for 30 minutes. The precipitate is filtered off with suction, washed thoroughly with H2O and dried under a high vacuum at 40°. The substance, which still contains a large amount of pyridine hydrochloride, is dissolved in CH2Cl2 and the organic phase is washed twice with water, once with 1N hydrochloric acid and again with water. After drying over Na2SO4 and concentration in a rotary evaporator, the residue is recrystallised from CH2Cl2 /hexane, yielding cholesteryl tosylate; m.p. 130°-131°.

1. additionWhen the addition
2. temperaturewith cooling
3. customThe ice-bath is then removed
4. stirringthe mixture is stirred for 2 days at room temperature
5. customthe reaction
6. stirringstirred for 30 minutes
7. filtrationThe precipitate is filtered off with suction
8. washwashed thoroughly with H2O
9. customdried under a high vacuum at 40°
10. dissolutionis dissolved in CH2Cl2
11. washthe organic phase is washed twice with water, once with 1N hydrochloric acid and again with water
12. dry with materialAfter drying over Na2SO4 and concentration in a rotary evaporator
13. customthe residue is recrystallised from CH2Cl2 /hexane