scholarly journals Cytostatic and Antiviral 6-Arylpurine Ribonucleosides IX. Synthesis and Evaluation of 6-Substituted 3-Deazapurine Ribonucleosides

2008 ◽  
Vol 73 (5) ◽  
pp. 665-678 ◽  
Author(s):  
Petr Nauš ◽  
Martin Kuchař ◽  
Michal Hocek
Keyword(s):  
Antiviral Activity ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Alkyl Aryl ◽  
Cross Coupling Reactions

A series of 3-deazapurine ribonucleosides 5a-5l bearing diverse C-substituents (alkyl, aryl and heteroaryl) in the position 6 were prepared by Pd-catalyzed cross-coupling reactions of either free 6-chloro-3-deazapurine ribonucleoside 4 or its acetyl protected congener 3 followed by deprotection. An improved synthesis of the starting 4-chloro-1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-1H-imidazo[4,5-c]pyridine (3) was developed by the application of Vorbrüggen glycosylation of silylated nucleobase with 1,2,3,5-tetra-O-acetyl-β-D-ribofuranose (2). None of compounds 5a-5l showed any considerable cytostatic or antiviral activity.

Sugar-modified derivatives of cytostatic 6-(het)aryl-7-deazapurine nucleosides: 2′-C-methylribonucleosides, arabinonucleosides and 2′-deoxy-2′-fluoroarabinonucleosides

2011 ◽  
Vol 76 (8) ◽  
pp. 957-988 ◽  
Author(s):  
Petr Nauš ◽  
Pavla Perlíková ◽  
Radek Pohl ◽  
Michal Hocek
Keyword(s):  
Antiviral Activity ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Alkyl Aryl ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
Derivatives Of

A series of novel sugar-modified derivatives of cytostatic 6-hetaryl-7-deazapurine ribonucleosides: 2′-C-methylribonucleosides, arabinonucleosides and 2′-deoxy-2′-fluoroarabinonucleosides bearing an alkyl, aryl and hetaryl group in position 6 were prepared by palladium catalyzed cross-coupling reactions of corresponding (protected) 6-chloro-(7-fluoro)-7-deazapurine nucleosides with (het)arylboronic, hetarylstannanes and trimethylaluminium eventually followed by deprotection. Key intermediate 6-chloro-7-deazapurine 2′-C-methyl-β-D-ribofuranoside was prepared via a stereoselective nucleobase anion glycosylation with toluoyl-protected 1,2-anhydro-2-C-methylribofuranose. The 1,2-anhydro sugar was synthesized in 3 steps starting from readily available 2-C-methylribonolactone. The 6-chloro-7-deazapurine arabinofuranoside intermediate was obtained by epimerization from 3′,5′-protected 6-chloro-7-deazapurine ribofuranoside via 2′-hydroxyl oxidation followed by reduction. None of the prepared compounds showed any considerable cytostatic or antiviral activity.

The synthesis of the 8-C-substituted 2,6-diamino-9-[2-(phosphonomethoxy)ethyl]purine (PMEDAP) derivatives by diverse cross-coupling reactions

2011 ◽  
Vol 89 (4) ◽  
pp. 488-498 ◽  
Author(s):  
Ondřej Sedláček ◽  
Petra Břehová ◽  
Radek Pohl ◽  
Antonín Holý ◽  
Zlatko Janeba
Keyword(s):  
Antitumor Activity ◽  
Antiviral Activity ◽  
Parent Compound ◽  
Cross Coupling ◽  
Starting Material ◽  
Coupling Reactions ◽  
Systematic Screening ◽  
Cross Coupling Reactions

Diisopropyl 8-bromo-2,6-diamino-9-[2-(phosphonomethoxy)ethyl]purine was used as a starting material for the synthesis of the 8-C-substituted 2,6-diamino-9-[2-(phosphonomethoxy)ethyl]purine (PMEDAP) analogues. A systematic screening of diverse cross-coupling reactions was carried out. Stille, Suzuki–Miyaura, Negishi, and Sonogashira cross-couplings, as well as Pd-catalysed reactions with trialkylaluminiums, were employed for the introduction of various alkyl, alkenyl, alkynyl, aryl, and hetaryl substituents to the C-8 position of the 2,6-diaminopurine moiety. In contrast to the potent parent compound PMEDAP, which exhibits potent antiretroviral and antitumor activity, none of the sixteen newly synthesized 8-C-substituted analogues of PMEDAP showed any specific antiviral activity.

Cytostatic and Antiviral 6-Arylpurine Ribonucleosides VIII. Synthesis and Evaluation of 6-Substituted Purine 3'-Deoxyribonucleosides

2006 ◽  
Vol 71 (10) ◽  
pp. 1484-1496 ◽  
Author(s):  
Michal Hocek ◽  
Peter Šilhár ◽  
Radek Pohl
Keyword(s):  
Cross Coupling ◽  
Cytostatic Activity ◽  
Coupling Reactions ◽  
Alkyl Aryl ◽  
Cross Coupling Reactions

A series of purine 3'-deoxyribonucleosides bearing diverse C-substituents (alkyl, aryl, hetaryl or hydroxymethyl) in the position 6 was prepared by Pd-catalyzed cross-coupling reactions of 6-iodo-9-[2,5-bis-O-(tert-butyldimethylsilyl)-3-deoxy-β-D-ribofuranosyl]purine with the corresponding organometallics followed by deprotection by (HF)3·Et3N. None of the title 3'-deoxyribonucleoside showed any cytostatic activity or anti-HCV effect in replicon assay.

Cu(0)@Al2O3/SiO2 NPs: an efficient reusable catalyst for the cross coupling reactions of aryl chlorides with amines and anilines

RSC Advances ◽  
2015 ◽  
Vol 5 (112) ◽  
pp. 92121-92127 ◽  
Author(s):  
P. Linga Reddy ◽  
R. Arundhathi ◽  
Diwan S. Rawat
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Reusable Catalyst ◽  
Coupling Reactions ◽  
Silica Support ◽  
Alkyl Aryl ◽  
Aryl Chlorides ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Aryl Amines

The C–N cross coupling reaction of aryl chlorides with various alkyl/aryl amines catalyzed by copper nanoparticles impregnated on alumina/silica support (Cu(0)@Al2O3/SiO2) was investigated and the catalyst showed excellent reactivity and efficacy.

scholarly journals Synthesis of (purin-6-yl)acetates and their transformations to 6-(2-hydroxyethyl)- and 6-(carbamoylmethyl)purines

2009 ◽  
Vol 74 (7-8) ◽  
pp. 1035-1059 ◽  
Author(s):  
Zbyněk Hasník ◽  
Radek Pohl ◽  
Blanka Klepetářová ◽  
Michal Hocek
Keyword(s):  
Antiviral Activity ◽  
Cross Coupling ◽  
Significant Activity ◽  
Coupling Reactions ◽  
Nucleophilic Substitutions ◽  
Purine Bases ◽  
Cross Coupling Reactions ◽  
Novel Approach ◽  
Reformatsky Reagent ◽  
Activity Screening

A novel approach to the synthesis of (purin-6-yl)acetates was developed based on Pd-catalyzed cross-coupling reactions of 6-chloropurines with a Reformatsky reagent. Their reduction with NaBH4 and treatment with MnO2 gave 6-(2-hydroxyethyl)purines, while reactions with amines in presence of NaCN afforded 6-(carbamoylmethyl)purines. Mesylation of the 6-(2-hydroxyethyl)purines followed by nucleophilic substitutions gave rise to several 6-(2-substituted ethyl)purines. This methodology was successfully applied to the synthesis of substituted purine bases and nucleosides for cytostatic and antiviral activity screening. None of the compounds exerted significant activity.

Dual Nickel/Palladium-Catalyzed Reductive Cross-Coupling Reactions Between Two Phenol Derivatives

2020 ◽  
Author(s):  
Baojian Xiong ◽  
Yue Li ◽  
Yin Wei ◽  
Søren Kramer ◽  
Zhong Lian
Keyword(s):  
Functional Group ◽  
Low Cost ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Phenol Derivatives ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
One Step ◽  
Aryl Tosylates ◽  
Low Sensitivity

Cross-coupling between substrates that can be easily derived from phenols is highly attractive due to the abundance and low cost of phenols. Here, we report a dual nickel/palladium-catalyzed reductive cross-coupling between aryl tosylates and aryl triflates; both substrates can be accessed in just one step from readily available phenols. The reaction has a broad functional group tolerance and substrate scope (>60 examples). Furthermore, it displays low sensitivity to steric effects demonstrated by the synthesis of a 2,2’disubstituted biaryl and a fully substituted aryl product. The widespread presence of phenols in natural products and pharmaceuticals allow for straightforward late-stage functionalization, illustrated with examples such as Ezetimibe and tyrosine. NMR spectroscopy and DFT calculations indicate that the nickel catalyst is responsible for activating the aryl triflate, while the palladium catalyst preferentially reacts with the aryl tosylate.

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