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.

trans-Stilbene as a Starting Material for the Synthesis of Tamoxifen Based on Palladium-Catalyzed Cross-Coupling Reactions

Synthesis ◽  
2009 ◽  
Vol 2009 (16) ◽  
pp. 2761-2765 ◽  
Author(s):  
Adriano Monteiro ◽  
Carolina Nunes ◽  
Jones Limberger ◽  
Silvia Poersch ◽  
Marcus Seferin
Keyword(s):  
Cross Coupling ◽  
Starting Material ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Trans Stilbene ◽  
Palladium Catalyzed

scholarly journals Remarkable effect of alkynyl substituents on the fluorescence properties of a BN-phenanthrene

2019 ◽  
Vol 15 ◽  
pp. 1257-1261 ◽  
Author(s):  
Alberto Abengózar ◽  
David Sucunza ◽  
Patricia García-García ◽  
Juan J Vaquero
Keyword(s):  
Quantum Yield ◽  
Fluorescence Quantum Yield ◽  
Triple Bond ◽  
Photophysical Properties ◽  
Parent Compound ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Remarkable Effect ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed

A series of BN-phenanthrenes with substituents of a diverse nature have been synthesized by palladium-catalyzed cross-coupling reactions of a common chloro-substituted precursor, which was made from readily available materials in only four steps. Evaluation of the photophysical properties of the prepared compounds unveiled an impressive effect of the presence of alkynyl substituents on the fluorescence quantum yield, which improved from 0.01 in the parent compound to up to 0.65 in derivatives containing a triple bond.

scholarly journals Efficient Access to 3,5-Disubstituted 7-(Trifluoromethyl)pyrazolo[1,5-a]pyrimidines Involving SNAr and Suzuki Cross-Coupling Reactions

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2062 ◽  
Author(s):  
Badr Jismy ◽  
Abdellatif Tikad ◽  
Mohamed Akssira ◽  
Gérald Guillaumet ◽  
Mohamed Abarbri
Keyword(s):  
Kinase Inhibitors ◽  
Cross Coupling ◽  
Boronic Acids ◽  
Starting Material ◽  
Coupling Reactions ◽  
Synthetic Methodology ◽  
Type Reaction ◽  
Cross Coupling Reactions ◽  
Pim1 Kinase ◽  
Efficient Access

An efficient and original synthesis of various 3,5-disubstituted 7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidines is reported. A library of compounds diversely substituted in C-3 and C-5 positions was easily prepared from a common starting material, 3-bromo-7-(trifluoromethyl)pyrazolo[1,5-a]pyrimidin-5-one. In C-5 position, a SNAr type reaction was achieved by first activating the C–O bond of the lactam function with PyBroP (Bromotripyrrolidinophosphonium hexafluorophosphate), followed by the addition of amine or thiol giving monosubstituted derivatives, whereas in C-3 position, arylation was performed via Suzuki–Miyaura cross-coupling using the commercially available aromatic and heteroaromatic boronic acids. Moreover, trifluoromethylated analogues of potent Pim1 kinase inhibitors were designed following our concise synthetic methodology.

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.

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.

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.

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.

An Iron-Based Catalyst Enables The Enantioconvergent Synthesis of Chiral 1,1-Diarylalkanes Through a Suzuki-Miyaura Cross-Coupling Reaction

2020 ◽  
Author(s):  
Chet Tyrol ◽  
Nang Yone ◽  
Connor Gallin ◽  
Jeffery Byers
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Radical Intermediates ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Boronic Esters ◽  
Carbon Centered Radical ◽  
Iron Based ◽  
High Yields

By using an iron-based catalyst, access to enantioenriched 1,1-diarylakanes was enabled through an enantioselective Suzuki-Miyaura crosscoupling reaction. The combination of a chiral cyanobis(oxazoline) ligand framework and 1,3,5-trimethoxybenzene additive were essential to afford high yields and enantioselectivities in cross-coupling reactions between unactivated aryl boronic esters and a variety of benzylic chlorides, including challenging ortho-substituted benzylic chloride substrates. Mechanistic investigations implicate a stereoconvergent pathway involving carbon-centered radical intermediates.

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