ОПТИМИЗАЦИЯ СИНТЕЗА 2'- О-α- D-РИБОФУРАНОЗИЛАДЕНОЗИНА ПО МЕТОДУ СИМПЛЕКСНОГО ПЛАНИРОВАНИЯ

Disaccharide nucleosides belong to an important group of natural compounds found in t-RNA and poly(ADPribose). They are also key elements in the structure of antibiotics and other physiologically active compounds. Poly(ADP-ribosylation) is a posttranslational modification of proteins in eukariotic cells catalyzed by poly(ADPribose)-polymerazes. The importance of poly(ADP-ribose) has been established in many cellular processes such as DNA replication, recombination and repair and cellular differentiation. The development of the synthesis of poly(ADP-ribose) and it’s components is still a challenging problem. The synthesis of 2'-O-α-D-ribofuranosyladenosine, a monomeric unit of poly(ADP-ribose) reported earlier has been improved. An important step on this way is the formation of a 2'-O-glycosidic bond between the adenosine and carbohydrate moieties. A new strategy involving glycosylation of 3',5'-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl)adenosine has been suggested. Varying of the catalyst (SnCl4), nucleoside and carbohydrate relations by the simplex method allowed improving the yields in the glycosylation step from 35 to 64%. As a result, it made possible to reach a higher overall yield of 2'-O-α-D-ribofuranosyladenosine in comparison with the literature data.С помощью метода симплексного планирования оптимизирован синтез 2'-O-α-D-рибофура-нозиладенозина - мономерного звена поли(АDP-рибозы). Подбор оптимальных соотношений катализатора (SnCl4), нуклеозида и углеводной компоненты позволил повысить выходы на стадии гликозилирования с 35 до 64%

Distinct Peculiarities of In Planta Synthesis of Isoprenoid and Aromatic Cytokinins

The biosynthesis of aromatic cytokinins in planta, unlike isoprenoid cytokinins, is still unknown. To compare the final steps of biosynthesis pathways of aromatic and isoprenoid cytokinins, we synthesized a series of nucleoside derivatives of natural cytokinins starting from acyl-protected ribofuranosyl-, 2′-deoxyribofuranosyl- and 5′-deoxyribofuranosyladenine derivatives using stereoselective alkylation with further deblocking. Their cytokinin activity was determined in two bioassays based on model plants Arabidopsis thaliana and Amaranthus caudatus. Unlike active cytokinins-bases, cytokinin nucleosides lack the hormonal activity until the ribose moiety is removed. According to our experiments, ribo-, 2′-deoxyribo- and 5′-deoxyribo-derivatives of isoprenoid cytokinin N6-isopentenyladenine turned in planta into active cytokinins with clear hormonal activity. As for aromatic cytokinins, both 2′-deoxyribo- and 5′-deoxyribo-derivatives did not exhibit analogous activity in Arabidopsis. The 5′-deoxyribo-derivatives cannot be phosphorylated enzymatically in vivo; therefore, they cannot be “activated” by the direct LOG-mediated cleavage, largely occurring with cytokinin ribonucleotides in plant cells. The contrasting effects exerted by deoxyribonucleosides of isoprenoid (true hormonal activity) and aromatic (almost no activity) cytokinins indicates a significant difference in the biosynthesis of these compounds

Distinct Peculiarities of In Planta Synthesis of Isoprenoid and Aromatic Cytokinins

The biosynthesis of aromatic cytokinins in planta, unlike isoprenoid cytokinins, is still unknown. To compare the final steps of biosynthesis pathways of aromatic and isoprenoid cytokinins, we synthesized a series of nucleoside derivatives of natural cytokinins starting from acyl-protected ribofuranosyl-, 2′-deoxyribofuranosyl- and 5′-deoxyribofuranosyladenine derivatives using stereoselective alkylation with further deblocking. Their cytokinin activity was determined in two bioassays based on model plants Arabidopsis thaliana and Amaranthus caudatus. Unlike active cytokinins-bases, cytokinin nucleosides lack the hormonal activity until the ribose moiety is removed. According to our experiments, ribo-, 2′-deoxyribo- and 5′-deoxyribo-derivatives of isoprenoid cytokinin N6-isopentenyladenine turned in planta into active cytokinins with clear hormonal activity. As for aromatic cytokinins, both 2′-deoxyribo- and 5′-deoxyribo-derivatives did not exhibit analogous activity in Arabidopsis. The 5′-deoxyribo-derivatives cannot be phosphorylated enzymatically in vivo; therefore, they cannot be “activated” by the direct LOG-mediated cleavage, largely occurring with cytokinin ribonucleotides in plant cells. The contrasting effects exerted by deoxyribonucleosides of isoprenoid (true hormonal activity) and aromatic (almost no activity) cytokinins indicates a significant difference in the biosynthesis of these compounds.</jats:p

Regioselective 1-N-Alkylation and Rearrangement of Adenosine Derivatives

<div><p>GRAPHICAL ABSTRACT</p><p></p></div

OPTIMIZATION OF 2'-О-α-D-RIBOFURANOSYLADENOSINE SYNTHESIS USING THE SIMPLEX PLANNING METHOD

Disaccharide nucleosides belong to an important group of natural compounds found in t-RNA and poly(ADPribose). They are also key elements in the structure of antibiotics and other physiologically active compounds. Poly(ADP-ribosylation) is a posttranslational modification of proteins in eukariotic cells catalyzed by poly(ADPribose)-polymerazes. The importance of poly(ADP-ribose) has been established in many cellular processes such as DNA replication, recombination and repair and cellular differentiation. The development of the synthesis of poly(ADP-ribose) and it’s components is still a challenging problem. The synthesis of 2'-O-α-D-ribofuranosyladenosine, a monomeric unit of poly(ADP-ribose) reported earlier has been improved. An important step on this way is the formation of a 2'-O-glycosidic bond between the adenosine and carbohydrate moieties. A new strategy involving glycosylation of 3',5'-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl)adenosine has been suggested. Varying of the catalyst (SnCl4), nucleoside and carbohydrate relations by the simplex method allowed improving the yields in the glycosylation step from 35 to 64%. As a result, it made possible to reach a higher overall yield of 2'-O-α-D-ribofuranosyladenosine in comparison with the literature data