Method for Isolation of Cytisine

• Main Authors: Metodiev, Danail Georgiev, Apostolova, Petya Mitkova, Klisarova, Maria Nedkova, Stoyanov, Nikolay Kirilov, Zaekova, Galina Nikolova
• Format: Patent
• Language: English
• Published: 19.11.2020
• Subjects: CHEMISTRY; HETEROCYCLIC COMPOUNDS; METALLURGY; ORGANIC CHEMISTRY; PERFORMING OPERATIONS; PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL; SEPARATION; TRANSPORTING

The invention discloses a new method for purifying cytisine from raw plant extracts that yields high purity. The method comprises the steps of dissolving raw plant material with a lower alcohol, such as methanol or ethanol, then acidifying with mineral acid to a pH between 1.5 and 3.5. The combined alcohol-aqueous extracts are concentrated under vacuum distillation until the alcohol is eliminated and after filtration they are extracted with chloroform, methylene chloride, butyl acetate or normal butanol in a ratio of 1:1. The purified from ballast substances acid aqueous concentrate is alkalized to a pH of between 9 and 12 with alkaline hydroxide or ammonium hydroxide and the resulting alkaline aqueous concentrate is extracted at least twice with chloroform, methylene chloride, butyl acetate or normal butanol in a ratio of concentrate to extractant of from 1:5 to 1:10. The combined organic extracts are evaporated to dryness, then acetone or ethyl acetate are added to obtain a suspension which is allowed to crystallize completely at a temperature of from 5-10° C., then it is filtered and dried. The isolated final cytisine product has high purity and yield than otherwise known methods in the art.