The use of endemic plant raw materials in folk medical practice has a centuries-old history and acts as a resource base for traditional medical practices, widespread primarily in rural areas. Statistics are known that 80% of the world's modern population relies on traditional herbal medicine for primary health care [1, 2].
Synthetic transformations of natural compounds have become one of the foundations of organic synthesis and medical chemistry. An attractive factor is the availability of natural metabolites, due to the prevalence of sources and technological methods of isolation of natural substances [1].
Currently, biologically active compounds based on plants and their transformation products are used to maintain and promote a healthy lifestyle, prevent diseases and treat ailments. The pharmacological effect of such drugs primarily depends on their chemical composition, which is often complex, multicomponent in nature, which is accompanied by difficulties in isolating the main components and in their normalization [2].
Among the many extractive substances from plant raw materials, pentacyclic triterpenoids from birch bark, especially betulin, occupy a special place. Betulin can actually be considered the first biologically active substance isolated from a plant source on an industrially significant scale.
The sufficient raw material base and a wide range of biological activity of betulin place it in a number of valuable natural sources for use both in the native state and in the form of various transformation products, and also make the development of medicines based on it relevant [3].
It has been proven that betulin and its derivatives exhibit antiseptic, antiviral and antioxidant properties, have hepatoprotective, choleretic, antifungal and antitumor effects [3-5].
It has been proven that betulin and its derivatives exhibit antiseptic, antiviral and antioxidant properties, have hepatoprotective, choleretic, antifungal and antitumor effects [6].
Thus, the purpose of the work is to develop a strategy for the synthesis of new aminobetulines based on a renewable natural source of raw materials.
In accordance with the set goal, the following tasks were solved:
1. To obtain the initial substrates and reagents: isolate, purify betulin and identify its structure using IR and NMR spectroscopy methods.
2. To synthesize 3,28-O-diacetylbetulin and identify its structure using IR and NMR spectroscopy methods.
3. To perform bromination of 3,28-O-diacetylbetulin with N- bromosuccinimide and tetrabromoglycoluryl and identify the products using IR and NMR spectroscopy methods.
4. To study the conditions for the conversion of halogen derivatives of betulin into aminobetulines using the example of anaesthesin.
5. To identify the obtained amination products using IR and NMR spectroscopy methods.
In the course of the work we have done, we have obtained the following results:
1. The initial substrates and reagents were isolated and identified: betulin and
3.28- O-diacetylbetulin with yields of 15% and 91%, respectively.
2. The conditions of bromination of 3,28-O-diacetylbetulin with tetrabromoglycoluryl om and N-bromosuccinimide have been studied. It was found that the bromination of 3,28-O-diacetylbetulin forms a mixture of isomers, which complicates further research. The initiator of radical reactions, azobisisobutyronitrile, was used for the selective course of the reaction to the allyl position of the isopropenyl fragment. As a result, 3,28-O-diacetyl-30-bromolup- 20(29)-en was formed with a yield of 49%.
3. The reaction of conversion of 3,28-O-diacetyl-30-bromolup-20(29)-en into
3.28- O-diacetyl-30-(1-amino-4-ethyl benzoate)lup-20(29)-en was carried using anaesthesin.
4. All compounds obtained during the work were identified using IR and 1H NMR and 13C NMR spectroscopy.
