Ouverture regioselective d'alcools tetrahydrofuranniques par Me3SiCl/NaI synthese de L'exo-ET DE L'endo-brevicomine

Me₃SiCl/NaI in acetone opens regioselectively tetrahydrofurfurylalcohols and hydroxy-3 tetrahydrofuran to give the corresponding iodoacetonides in good yields. An application to the synthesis of the exo-and endo-brevicomins is described.     

Development and Validation of a UHPLC UV Method for the In-Process Control of Bosentan Monohydrate Synthesis

Bosentan monohydrate (4-tert-butyl-N-[6-(2-hydroxyethoxy)-5-(2-methoxyphenoxy)-2-(pyrimidin-2-yl) pyrimidin-4-yl]benzene-1-sulfonamide monohydrate) is a dual endothelin receptor antagonist (ERA) applied in the treatment of pulmonary arterial hypertension. To achieve effective process control of the bosentan monohydrate synthesis, it was necessary to develop a selective and not highly time-consuming method for ultra-high performance liquid chromatography (UHPLC). The method is characterized by adequate sensitivity, reproducibility and selectivity for the determination of bosentan monohydrate and related compounds from all synthetic stages. The UHPLC separation was carried out by reversed phase chromatography on the Acquity BEH C18 column (100 mm × 2.1 mm, 1.7 µm) with a mobile phase composed of solvent A (0.1 %, v/v, acetic acid in water) and solvent B (methanol), in the gradient mode at the flow rate of 0.4 mL min⁻¹. Limits of detection and quantification for the compounds were ≤0.1 µg mL⁻¹ and 0.3 µg mL⁻¹, respectively. The linearity for all related compounds was investigated as in the range for the active pharmaceutical ingredient (API) and as in the range for the in-process control. The developed method was validated according to the current guidelines, proving the suitability of the method for its intended purpose.

     

Preparation of selectively protected protoescigenin derivatives for synthesis of escin analogs and neoglycoconjugates

Protoescigenin, the main aglycone of horse chestnut saponin mixture known as escin, was selected as substrate for exploratory chemistry towards selective protection, followed by propargyl ether formation and subsequent condensation with azido-monosaccharides, to obtain novel triazole linked conjugates of the triterpene.