METHOD FOR OBTAINING FLUORESCEIN-5-ISOTHIOCYANATE Russian patent published in 2022 - IPC C07D311/82 

FIELD: medical diagnostics.

SUBSTANCE: invention relates to a method for producing fluorescein-5-isothiocyanate, which can be used as an immunofluorescent dye or a fluorescent protein tag for the rapid diagnosis of viral infections. The method consists in the interaction of 5-aminofluorescein with a sulfur-containing compound, followed by the release of the target product. Carbon disulfide is used as a sulfur-containing compound and the reaction of 5-aminofluorescein with carbon disulfide is carried out in the presence of triethylamine at their molar ratio, respectively, equal to 0.048:0.25:0.4. In this case, carbon disulfide and triethylamine are initially mixed in a pyridine medium, after which a solution of 5-aminofluorescein in pyridine or dimethylformamide is added to the resulting solution at 0°C and the resulting reaction mass is mixed at the same temperature for 4.5-5.5 hours. Then it is mixed with an aqueous solution containing 0.05 moles of a heavy metal salt selected from the group: lead, copper, bismuth, after which the resulting solution is acidified to pH 6.5-7 and the precipitate is filtered, washed with distilled water and dried, after which it is extracted with boiling acetone, the acetone extract is evaporated, cooled, filtered and washed with chloroform.

EFFECT: proposed method makes it possible to obtain fluorescein-5-isothiocyanate with good yields and purity.

3 cl, 3 ex