- The reaction of amino-imidazoles, -pyrazoles and -triazoles with α,β-unsaturated nitriles
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The reactions of α,β-unsaturated nitriles (1, 9, 12) as bielectrophiles with aminoazoles (2, 4, 6) as binucleophiles were investigated. Acrylonitrile (1) reacts almost exclusively in a chemoselective Michael-type addition yielding the substituted azoles 3, 5 and 7, respectively. Cinnamonitriles 9a,b behave in a similar way, but the free CN group adds a second molecule 4 yielding 10a,b and its cyclocondensation product 11a,b as minor component. The attempted formation of azolopyrimidines is best achieved by the reaction of the benzylidenemalononitriles 12a - f with 2 or 4. The process is chemo- and regioselective. The structure determinations were based on NMR measurements including DEPT, COSY, ROESY, HMQC and HMBC techniques and correct earlier suggestions.
- Komykhov, Sergey A.,Ostras, Konstantin S.,Kostanyan, Alvard R.,Desenko, Sergey M.,Orlov, Valery D.,Meier, Herbert
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- Approach to the library of fused pyridine-4-carboxylic acids by combes-type reaction of acyl pyruvates and electron-rich amino heterocycles
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A library of fused pyridine-4-carboxylic acids (including pyrazolo[3,4-b]pyridines, isoxazolo[5,4-b]pyridines, furo[2,3-b]pyridines, thieno[2,3-b]pyridines, and pyrido[2,3-d]pyrimidines) was generated by Combes-type reaction of acyl pyruvates and electron-rich amino heterocycles followed by hydrolysis of the ester. The library members were also demonstrated to undergo the standard combinatorial transformations including amide coupling and esterification, as well as less common heterocyclizations to 1,2,4-triazoles and 1,2,4-oxadiazoles.
- Volochnyuk, Dmitriy M.,Ryabukhin, Sergey V.,Plaskon, Andrey S.,Dmytriv, Yuri V.,Grygorenko, Oleksandr O.,Mykhailiuk, Pavel K.,Krotko, Dmitriy G.,Pushechnikov, Alexei,Tolmachev, Andrey A.
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scheme or table
p. 510 - 517
(2010/09/05)
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