A Short Synthesis of the Plant Alkaloid 4-Methyl-2,6-naphthyridine

2019 ◽  
Vol 16 (12) ◽  
pp. 931-934 ◽  
Author(s):  
Alexandra Kamlah ◽  
Franz Bracher
Keyword(s):  
Pyridine Ring ◽  
Cross Coupling ◽  
Antirrhinum Majus ◽  
New Synthesis ◽  
Short Synthesis ◽  
Regioselective Oxidation ◽  
Key Steps

: A new synthesis of the 2,6-naphthyridine alkaloid 4-methyl-2,6-naphthyridine from Antirrhinum majus has been developed. Key steps are a regioselective oxidation of 3-bromo-4,5- dimethylpyridine to the corresponding 4-formyl derivative, and the annulation of the second pyridine ring by Suzuki-Miyaura cross-coupling using (E)-2-ethoxyvinylboronic acid pinacol ester as a masked acetaldehyde equivalent. This protocol gives the alkaloid in four steps starting from commercially available 3,4-dimethylpyridine in 15% overall yield. This annulation protocol should be useful for the synthesis of other condensed pyridines as well.

ChemInform Abstract: A New Synthesis of Butadienyl- and Styrylboronic Esters: Highly Reactive Intermediates for Suzuki Cross-Coupling.

ChemInform ◽  
2010 ◽  
Vol 33 (34) ◽  
pp. no-no
Author(s):  
Paolo Balma Tivola ◽  
Annamaria Deagostino ◽  
Cristina Prandi ◽  
Paolo Venturello
Keyword(s):  
Cross Coupling ◽  
Reactive Intermediates ◽  
New Synthesis

New Synthesis of 1,3-Dihydro-1,4-benzodiazepin-2(2H)-ones and 3-Amino-1,3-dihydro-1,4-benzodiazepin-2(2H)-ones:  Pd-Catalyzed Cross-Coupling of Imidoyl Chlorides with Organoboronic Acids

2003 ◽  
Vol 68 (7) ◽  
pp. 2844-2852 ◽  
Author(s):  
Alan Nadin ◽  
José M. Sánchez López ◽  
Andrew P. Owens ◽  
Dean M. Howells ◽  
Adam C. Talbot ◽  
...  
Keyword(s):  
Cross Coupling ◽  
New Synthesis ◽  
Organoboronic Acids ◽  
Imidoyl Chlorides

scholarly journals Electron-Deficient Acetylenes as Three-Modal Adjuvants in SNH Reaction of Pyridinoids with Phosphorus Nucleophiles

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6824
Author(s):  
Boris A. Trofimov ◽  
Pavel A. Volkov ◽  
Anton A. Telezhkin
Keyword(s):  
Nucleophilic Addition ◽  
Pyridine Ring ◽  
Cross Coupling ◽  
Secondary Phosphine ◽  
Metal Free ◽  
Secondary Phosphine Chalcogenides ◽  
Heterocyclic Moiety ◽  
Acid Esters ◽  
Phosphine Chalcogenides

Publications covering a new easy metal-free functionalization of pyridinoids (pyridines, quinolines, isoquinolines, acridine) under the action of the system of electron-deficient acetylenes (acetylenecarboxylic acid esters, acylacetylenes)/P-nucleophiles (phosphine chalcogenides, H-phosphonates) are reviewed. Special attention is focused on a SNH reaction of the regioselective cross-coupling of pyridines with secondary phosphine chalcogenides triggered by acylacetylenes to give 4-chalcogenophosphorylpyridines. In these processes, acetylenes act as three-modal adjuvants (i) activating the pyridine ring towards P-nucleophiles, (ii) deprotonating the P-H bond and (iii) facilitating the nucleophilic addition of the P-centered anion to a heterocyclic moiety followed by the release of the selectively reduced acetylenes (E-alkenes).

Synthesis of Biaryl Derivatives by Using Ruthenium-Mediated [2+2+2] Cyclotrimerization and Suzuki-Miyaura Cross-Coupling as Key Steps

Synthesis ◽  
2011 ◽  
Vol 2011 (10) ◽  
pp. 1581-1586 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Vittal Seema ◽  
Shaikh Mobin
Keyword(s):  
Cross Coupling ◽  
Key Steps

Tandem Schiff-Base Formation/Heterocyclization: An Approach to the Synthesis of Fused Pyrazolo–Pyrimidine/Isoxazolo-Pyrimidine Hybrids

Synlett ◽  
2019 ◽  
Vol 30 (05) ◽  
pp. 586-592 ◽  
Author(s):  
Manoranjan Behera ◽  
M. Sambaiah ◽  
Poosa Mallesham ◽  
K. Shiva Kumar ◽  
Yamini Bobde ◽  
...  
Keyword(s):  
Schiff Base ◽  
Pyrimidine Ring ◽  
Stille Coupling ◽  
New Synthesis ◽  
Schiff Base Formation ◽  
Key Steps ◽  
Base Formation

A new synthesis of pyrazolo[4,3-d]pyrimidines and isoxazolo[4,5-d]pyrimidines is described. Key steps in the synthesis involve Stille coupling of 4,6-dichloro-2-phenyl-pyrimidine with tributyl(1-ethoxyvinyl)stannane and tandem Schiff-base formation/heterocyclization of 2,6-di-aryl-5-fluoro-4-acetylpyrimidine with hydrazines or ­hydroxylamine to give pyrazolo[4,3-d]pyrimidines and isoxazolo[4,5-d]pyrimidines, respectively. The position of the fluoro group in the ­pyrimidine ring is important for the success of heterocylization reaction.

A Concise Enantioselective Synthesis of (S)-Preclamol via Asymmetric Catalytic Negishi Cross-Coupling Reaction

Synlett ◽  
2019 ◽  
Vol 30 (07) ◽  
pp. 860-862 ◽  
Author(s):  
Yun Zhou ◽  
Chunxiao Liu ◽  
Lifeng Wang ◽  
Leng Han ◽  
Shicong Hou ◽  
...  
Keyword(s):  
Total Yield ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Enantioselective Synthesis ◽  
Synthetic Approach ◽  
Chiral Drugs ◽  
Asymmetric Catalytic ◽  
Cross Coupling Reaction ◽  
Tertiary Carbon ◽  
Key Steps

A novel, concise, and efficient enantioselective synthesis of (S)-preclamol (87% ee, 51% total yield) has been developed. The key steps of this synthetic approach included cobalt-catalyzed asymmetric catalytic cross-coupling of α-bromo ester with arylzinc and the reduction of chiral ester to diol with a tertiary carbon atom. Moreover, it was demonstrated that our enantioselective Negishi cross-coupling was a powerful tool to construct stereogenic benzylmethyl center in chiral drugs on a gram scale.

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