Synthesis of Cytokinins via Enzymatic Arsenolysis of Purine Nucleosides

Abstract

This unit describes an effective method for the preparation of natural cytokinins and their synthetic derivatives based on enzymatic cleavage of the N‐glycosidic bond of N6‐substituted adenosine or O6‐substituted inosine derivatives in the presence of purine nucleoside phosphorylase (PNP) and Na2HAsO4. The arsenolysis reaction is irreversible due to the hydrolysis of the resulting α‐D‐ribose‐1‐arsenate. As a result, the desired products are formed in near‐quantitative yields, as indicated by high‐performance liquid chromatography (HPLC) analysis, and can easily be isolated. In the strategy used here, the ribose residue acts as a protective group. © 2018 by John Wiley & Sons, Inc.

Comparative Analysis of Enzymatic Transglycosylation Using E. coli Nucleoside Phosphorylases: A Synthetic Concept for the Preparation of Purine Modified 2′-Deoxyribonucleosides from Ribonucleosides

“…When preparing 2′-deoxynucleosides from ribonucleosides, N -glycosidic bond in nucleosides (donors of heterocyclic base) can be cleaved by two various enzymatic methods: enzymatic phosphorolysis in the presence of E. coli purine nucleoside phosphorylase and E. coli alkaline phosphatase [ 28 ] and by enzymatic arsenolysis in the presence of E. coli purine nucleoside phosphorylase and potassium dihydroorthoarsenate (KH 2 AsO 4 ) [ 29 , 37 , 38 ]. Synthesis of 3a – c by enzymatic arsenolysis and 3b by enzymatic phosphorolysis was described earlier [ 28 , 37 , 38 ]. In this work, 3a was obtained in enzymatic phosphorolysis conditions with lower yield (60%) than under arsenolysis conditions [ 25 ].…”

“…Ribonucleoside derivatives ( 1a , 1c ) were obtained by reaction of 6-chloropurine riboside derivatives with benzylamines [ 27 ], while compound ( 1b ) was obtained by alkylation of N 6 -acetyl-2′,3′,5′-tri-O-acetyladenosine by furfuryl alcohol under Misunobu conditions according to procedure [ 28 ]. Purine bases can be obtained by enzymatic arsenolysis ( 3a – c ) or enzymatic phosphorolysis ( 3b ) of corresponding ribonucleosides according to the previously described procedures [ 28 , 37 , 38 ]. 7-Methyl-2′-deoxyguanosine ( 4 ) was obtained as hydroiodic salt by a previously optimized method [ 13 , 39 ].…”

Intramolecular Hydrogen Bonding in N6-Substituted 2-Chloroadenosines: Evidence from NMR Spectroscopy

“…The nature of the substituent at the C2 position affects the presence of the mini-form in NMR. In the NMR spectra of substituted adenosines, the second form is usually registered as broadened signals at N 6 H-CH [16][17][18][19][20], or not registered at all. The NMR spectra of the purines with an electron-withdrawing substituent (Cl, F) at position 2 show the presence of the second form at room temperature [11], and the authors often do not discuss the second form, but it can be seen in NMR spectra in the Supplementary Information [21][22][23][24][25][26].…”