Abstract: A process for the preparation of a pharmaceutical-grade anhydrous calcipotriol comprising: (a) dissolving crude calcipotriol having a water content of X% by weight in a first solvent or in a mixture of two or more first solvents, said first solvent or said mixture of two or more first solvents forming an azeotropic system with water, to obtain a solution of crude calcipotriol; (b) obtaining an intermediate calcipotriol by (i) placing said solution of crude calcipotriol under a reduced pressure and evaporating, if X is greater than or equal to 1, or (ii) crystallizing, if X is lower than 1; and (c) re-dissolving said intermediate calcipotriol in a second solvent or a mixture of two or more second solvents, said second solvent being anhydrous, and crystallizing at least once to obtain pharmaceutical-grade anhydrous calcipotriol.

Abstract: Preparation of sulfonyl derivatives of cholecalciferol of Formula 1, wherein R1 is a protective group, preferably a t-butyl(dimethyl)silyl, and R2 is a heterocyclic group, such as a 2-thiazolyl, a 2-benzothiazolyl, a 1-phenyl-1H-tetrazo-5-yl, a 2-pyridyl, a 2-pyrimidynyl, a 1-isochinolinyl, a 1-methyl-2-imidazyl, or a 4-alkyl-1,2,4-triazo-3-yl, comprises the conversion of the hydroxyl derivative of cholecalciferol into the corresponding sulfide followed by its oxidation to the respective sulfone characterized by the use of a hydroxyl derivative of cholecalciferol as a starting material, in which the triene system is protected as a Diels-Alder adduct, and in particular as an adduct with sulfur dioxide of the Formula 2a. Novel are also the derivatives of Formula 3a and 4a, isolated in the process provided by the invention.

Abstract: A process for the preparation of a pharmaceutical-grade anhydrous calcipotriol comprising: (a) dissolving crude calcipotriol having a water content of X % by weight in a first solvent or in a mixture of two or more first solvents, said first solvent or said mixture of two or more first solvents forming an azeotropic system with water, to obtain a solution of crude calcipotriol; (b) obtaining an intermediate calcipotriol by (i) placing said solution of crude calcipotriol under a reduced pressure and evaporating, if X is greater than or equal to 1, or (ii) crystallizing, if X is lower than 1; and (c) re-dissolving said intermediate calcipotriol in a second solvent or a mixture of two or more second solvents, said second solvent being anhydrous, and crystallizing at least once to obtain pharmaceutical-grade anhydrous calcipotriol.