Heterocyclization Reactions of Pyruvic Acids and Aminoazoles with Controlled Chemoselectivity

Authors

  • Yana Sakhno
  • Maryna Murlykina
  • Alisa Morozova
  • Anton Kozyrev
  • Valentin Chebanov

DOI:

https://doi.org/10.17721/fujcV3I2P1-20

Keywords:

heterocyclization reaction, pyruvic acid, aminoazole, chemoselectivity, diversity oriented synthesis

Abstract

The present review includes the analysis of known literature data concerning linear and multicomponent heterocyclizations involving pyruvic acids and aminoazoles. In particular, the review demonstrates the approaches to control regio- and chemoselectivity of these types of treatments and their application to solve the matters of Diversity Oriented Synthesis.

References

Epling G, Lin K. Sulfur-containing 2-arylquinolinemethanols as potential antimalarials. Journal of Heterocyclic Chemistry 1987;24(3):853-857. https://doi.org/10.1002/jhet.5570240359

Saggiomo A, Kato K, Kaiya T. Fluorine-containing 4-quinolinemethanols as antimalarials. J. Med. Chem. 1968;11(2):277-281. https://doi.org/10.1021/jm00308a020

Atwell G, Baguley B, Denny W. Potential antitumor agents. 57. 2-Phenylquinoline-8-carboxamides as minimal DNA-intercalating antitumor agents with in vivo solid tumor activity. J. Med. Chem. 1989;32(2):396-401. https://doi.org/10.1021/jm00122a018

Bhatt DJ, Kamdar GC, Parikh AR. J Indian Chem Soc 1984;61:816.

Bergman J, Brynolf A. Synthesis of Chrysogine, a Metabolite of Penicillium chrysogenum and some related 2-substituted 4-(3H)-Quinazolinones. Tetrahedron 1990;46(4):1295-1310. https://doi.org/10.1016/s0040-4020(01)86694-1

Milyutin A, Amirova L, Kolla V, Nazmetdinov F, Drovosekova L, Andreichikov Y. Amides and hydrazides of aroylpyrivic acids. Part 6 Synthesis and study of antiinflammatory and analgesic activity of β-aroylpyruvoyl hydrazides of 2-methyl(phenyl)-4-quinolinecarboxylic acids. Pharm Chem J 1998;32(8):422-424. https://doi.org/10.1007/bf02465772

Aboul-Enein H, Ibrahim S. Synthesis and analgesic-anti-inflammatory activity of certain fluorinated cinchophen analogues. Journal of Fluorine Chemistry 1992;59(2):233-237. https://doi.org/10.1016/s0022-1139(00)82415-x

Miiyutin A, Makhmudov R, Andreichikov Y, Goleneva A, Tul'bovich G, Kovina T. Search for biologically active compounds in a series of α-acetylamino- and β-arylsulfonylaminoethylamides of aroylpyruvic acids. Pharm Chem J 1996;30(6):374-376. https://doi.org/10.1007/bf02219323

Doebner O. Ueber α-Alkylcinchoninsäuren. Berichte der deutschen chemischen Gesellschaft 1887;20(1):277-281. https://doi.org/10.1002/cber.18870200171

Döbner O, Gieseke M. 2) Ueber α-Phenylcinchoninsäure und ihre Homologen. Justus Liebigs Ann. Chem. 1887;242(3):290-300. https://doi.org/10.1002/jlac.18872420303

Borsche W. Über die Synthese α-substituierter Cinchoninsäuren nach Döbner. Berichte der deutschen chemischen Gesellschaft 1908;41(3):3884-3894. https://doi.org/10.1002/cber.19080410385

Borsche W. Neue Cinchoninsäure-Synthesen. Berichte der deutschen chemischen Gesellschaft 1909;42(3):4072-4088. https://doi.org/10.1002/cber.190904203172

Toma M. Gazz Chim Ital 1952;82:40.

Johnson J, Adams R. 2-PHENYLQUINOLINE-4-CARBOXYLIC ACID-6-ARSONIC ACID. 1 . J. Am. Chem. Soc. 1921;43(10):2255-2257. https://doi.org/10.1021/ja01443a019

NITIDANDHAPRABHAS O. Doebner's Reaction with 6-Methyl-2-amino Pyridine. Nature 1966;212(5061):504-505. https://doi.org/10.1038/212504b0

Eftekhari-Sis B, Zirak M. Chemistry of α-Oxoesters: A Powerful Tool for the Synthesis of Heterocycles. Chemical Reviews 2015;115(1):151-264. https://doi.org/10.1021/cr5004216

Herbert R, Kattah A, Knagg E. The Biosynthesis of the phenethylisoquinoline alkaloid colchicine. Early and intermediate stages. Tetrahedron 1990;46(20):7119-7138. https://doi.org/10.1016/s0040-4020(01)87895-9

Mitra A, De A, Karchaudhuri N. Application of Microwave Irradiation Techniques for the Syntheses of Cinnamic Acids by Doebner Condensation. Synthetic Communications 1999;29(4):573-581. https://doi.org/10.1080/00397919908085805

Um SJ, Park SH, Park CH, Chang BH, Yoon JH, Sin HS. Synthesis of Novel Quinolinecarboxamide Derivatives with Estrogenic Activity. Bulletin of the Korean Chemical Society 2003;24(5):677-680. https://doi.org/10.5012/bkcs.2003.24.5.677

MEYER W, VAUGHAN W. 1,5-Diaryl-2,3-pyrrolidinediones. IX. Reassignment of Structure1. The Journal of Organic Chemistry 1957;22(12):1560-1565. https://doi.org/10.1021/jo01363a006

VAUGHAN W, PETERS L. 2,3-PYRROLIDINEDIONES. I. PREPARATION AND STRUCTURE. The Journal of Organic Chemistry 1953;18(4):382-392. https://doi.org/10.1021/jo01132a006

Wang L, Hu L, Chen H, Sui Y, Shen W. One-pot synthesis of quinoline-4-carboxylic acid derivatives in water: Ytterbium perfluorooctanoate catalyzed Doebner reaction. Journal of Fluorine Chemistry 2009;130(4):406-409. https://doi.org/10.1016/j.jfluchem.2009.01.002

Muscia G, Carnevale J, Bollini M, Asís S. Microwave-assisted döbner synthesis of 2-phenylquinoline-4-carboxylic acids and their antiparasitic activities. Journal of Heterocyclic Chemistry 2008;45(2):611-614. https://doi.org/10.1002/jhet.5570450251

Saeed A, Elhadi S. Synthesis of Some 2-Aryl- and 2,3-Diaryl-quinolin-4-carboxylic Acid Derivatives. Synthetic Communications 2011;41(10):1435-1443. https://doi.org/10.1080/00397911.2010.486508

McCloskey C. 6-Nitrocinchophen and Related Substances 1 . J. Am. Chem. Soc. 1952;74(23):5922-5924. https://doi.org/10.1021/ja01143a029

Bhatt H, Agrawal Y, Patel M. Amino- and fluoro-substituted quinoline-4-carboxylic acid derivatives: MWI synthesis, cytotoxic activity, apoptotic DNA fragmentation and molecular docking studies. Medicinal Chemistry Research 2014;24(4):1662-1671. https://doi.org/10.1007/s00044-014-1248-x

Nixey T, Tempest P, Hulme C. Two-step solution-phase synthesis of novel quinoxalinones utilizing a UDC (Ugi/de-Boc/cyclize) strategy. Tetrahedron Letters 2002;43(9):1637-1639. https://doi.org/10.1016/s0040-4039(02)00101-6

Vinot N, Maitte P. Synthése de la benzopyranno[1][2,3- b ]quinoxalinone-12 . Journal of Heterocyclic Chemistry 1982;19(2):349-352. https://doi.org/10.1002/jhet.5570190226

Wiedermannová I, Slouka J. Synthesis of some isomeric quinoxaline derivatives with 6-azauracil cycle. Journal of Heterocyclic Chemistry 2001;38(6):1465-1468. https://doi.org/10.1002/jhet.5570380633

Colombo A, Frigola J, Parés J, Andaluz B. Synthesis of pyrazolo[3,4- b ][1,4]diazepines and pyrazolo[3,4- b ]pyrazines . Journal of Heterocyclic Chemistry 1989;26(4):949-955. https://doi.org/10.1002/jhet.5570260413

Holla BS, Sarojini BK, Rao BS, Poojary B. Chem Indian J Sect B 2003;42B:2054

Abelman M, Smith S, James D. Cyclic ketones and substituted α-keto acids as alternative substrates for novel Biginelli-like scaffold syntheses. Tetrahedron Letters 2003;44(24):4559-4562. https://doi.org/10.1016/s0040-4039(03)00985-7

Li W, Lam Y. Solid-Phase Synthesis of 3,4-Dihydro-1 H -pyrimidine-2-ones Using Sodium Benzenesulfinate as a Traceless Linker . J. Comb. Chem. 2005;7(5):721-725. https://doi.org/10.1021/cc0500295

Hussein HAR, KhM A. Egyptian J Chem 2007;50:725.

Rusinov V, Myasnikov A, Pilicheva T, Chupakhin O, Kiprianova E, Garagulya A. Antimicrobial activity of nitro derivatives of azolo[1,5-a]-pyrimidine and azolo[5,1-c][1,2,4]triazine. Pharm Chem J 1990;24(1):52-54. https://doi.org/10.1007/bf00769387

Desenko S, Lipson V, Gorbenko N, Pivovarevich L, Ryndina E, Moroz V, Varavin V. Synthesis and hypoglycemic activity of azolopyrimidine derivatives. Pharm Chem J 1995;29(4):265-266. https://doi.org/10.1007/bf02219551

Meng W, Brigance R, Chao H, Fura A, Harrity T, Marcinkeviciene J, O’Connor S, Tamura J, Xie D, Zhang Y, Klei H, Kish K, Weigelt C, Turdi H, Wang A, Zahler R, Kirby M, Hamann L. Discovery of 6-(Aminomethyl)-5-(2,4-dichlorophenyl)-7-methylimidazo[1,2- a ]pyrimidine-2-carboxamides as Potent, Selective Dipeptidyl Peptidase-4 (DPP4) Inhibitors . J. Med. Chem. 2010;53(15):5620-5628. https://doi.org/10.1021/jm100634a

Rusinov V, Pilicheva T, Chupakhin O, Kovalev G, Komina E. Cardiovascular activity of nitro derivatives of azolo[1,5-a]pyrimidine. Pharm Chem J 1986;20(8):550-554. https://doi.org/10.1007/bf00757634

Zeng L, Cai C. Iodine Catalyzed One-Pot Multicomponent Synthesis of a Library of Compounds Containing Tetrazolo[1,5- a ]pyrimidine Core . J. Comb. Chem. 2010;12(1):35-40. https://doi.org/10.1021/cc9000983

Zeng L, Ren Y, Cai C. Iodine-Catalyzed, Multicomponent, One-Pot Synthesis of 5-Aryl-5,8-dihydrotetrazolo[1,5- a ]pyrimidine-7-carboxylic Acids . Synthetic Communications 2011;41(24):3635-3643. https://doi.org/10.1080/00397911.2010.519842

El-borai M, Rizk H, Abd-Aal M, El-Deeb I. Synthesis of pyrazolo[3,4-b]pyridines under microwave irradiation in multi-component reactions and their antitumor and antimicrobial activities – Part 1. European Journal of Medicinal Chemistry 2012;48:92-96. https://doi.org/10.1016/j.ejmech.2011.11.038

Dias L, Santos M, Albuquerque S, Castro H, de Souza A, Freitas A, DiVaio M, Cabral L, Rodrigues C. Synthesis, in vitro evaluation, and SAR studies of a potential antichagasic 1H-pyrazolo[3,4-b]pyridine series. Bioorganic & Medicinal Chemistry 2007;15(1):211-219. https://doi.org/10.1016/j.bmc.2006.09.067

Chebanov VA, Desenko SM, YaI S, Panchenko ES, Saraev VE, Musatov VI, et al. Physiologically active substances 2002;33:10.

Chebanov V, Sakhno Y, Desenko S, Shishkina S, Musatov V, Shishkin O, Knyazeva I. Three-Component Procedure for the Synthesis of 5-Aryl-5,8-dihydroazolo[1,5- a ]pyrimidine-7-carboxylic Acids . Synthesis 2005;(15):2597-2601. https://doi.org/10.1055/s-2005-872073

Chebanov V, Desenko S. Multicomponent heterocyclization reactions with controlled selectivity (Review). Chemistry of Heterocyclic Compounds 2012;48(4):566-583. https://doi.org/10.1007/s10593-012-1030-2

Sedash Y, Gorobets N, Chebanov V, Konovalova I, Shishkin O, Desenko S. Dotting the i's in three-component Biginelli-like condensations using 3-amino-1,2,4-triazole as a 1,3-binucleophile. RSC Advances 2012;2(17):6719. https://doi.org/10.1039/c2ra20195j

Chebanov V, Gura K, Desenko S. Aminoazoles as Key Reagents in Multicomponent Heterocyclizations. Synthesis of Heterocycles via Multicomponent Reactions I 2010:41-84. https://doi.org/10.1007/7081_2009_21

Chebanov V, Desenko S, Gurley T. Introduction. Azaheterocycles Based on α, β-Unsaturated Carbonyls. Meppel: Springer; 2008. https://doi.org/10.1007/978-3-540-68367-4_1

Chebanov VA, Desenko SM. Switchable multicomponent heterocyclizations for diversity oriented synthesis. Diversity Oriented Synthesis 2014 Jan;1(1):43. https://doi.org/10.2478/dos-2014-0003

Zhu J, Wang Q, Wang MX. in Multicomponent Reactions in Organic Synthesis, Wiley-VCH. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA; 2014. https://doi.org/10.1002/9783527678174

Sakhno Y, Desenko S, Shishkina S, Shishkin O, Sysoyev D, Groth U, Oliver Kappe C, Chebanov V. Multicomponent cyclocondensation reactions of aminoazoles, arylpyruvic acids and aldehydes with controlled chemoselectivity. Tetrahedron 2008;64(49):11041-11049. https://doi.org/10.1016/j.tet.2008.09.089

Murlykina M, Sakhno Y, Desenko S, Shishkina S, Shishkin O, Sysoiev D, Kornet M, Schols D, Goeman J, Van der Eycken J, Van der Eycken E, Chebanov V. Study of the Chemoselectivity of Multicomponent Heterocyclizations Involving 3-Amino-1,2,4-triazole and Pyruvic Acids as Key Reagents, and Biological Activity of the Reaction Products. European Journal of Organic Chemistry 2015;2015(20):4481-4492. https://doi.org/10.1002/ejoc.201500469

Vaughan W, Covey I. 1,5-Diaryl-2,3-pyrrolidinediones. XI. Observations on Synthetic Methods and the Effect of 4-Substituents on Chemical Properties. J. Am. Chem. Soc. 1958;80(9):2197-2201. https://doi.org/10.1021/ja01542a041

Merchant J, Hakim M, Pillay K, Patell J. Synthesis and reactions of some pyrrolidinediones. J. Med. Chem. 1971;14(12):1239-1242. https://doi.org/10.1021/jm00294a033

Vaughan W, Tripp R. 1,5-Diaryl-2,3-pyrrolidinediones. XII. Enamines and the Pseudo-pyrrolidinediones 1,2 . J. Am. Chem. Soc. 1960;82(16):4370-4376. https://doi.org/10.1021/ja01501a064

Dieckmann W. Über die Einwirkung von Diazoessigester auf Benzaldehyd. Berichte der deutschen chemischen Gesellschaft 1910;43(1):1024-1031. https://doi.org/10.1002/cber.191004301175

Al-Najjar A, Bowden K, Vahid Horri M. Reactions of carbonyl compounds in basic solutions. Part 25.1 The mechanism of the base-catalysed ring fission of 3,4-diphenylcyclobut-3-ene-1,2-diones. J. Chem. Soc., Perkin Trans. 2 1997;(5):993-996. https://doi.org/10.1039/a606412d

Chernyshev V, Astakhov A, Starikova Z. Reaction of 1-substituted 3,5-diamino-1,2,4-triazoles with β-keto esters: synthesis and new rearrangement of mesoionic 3-amino-2H-[1,2,4]triazolo-[4,3-a]pyrimidin-5-ones. Tetrahedron 2010;66(18):3301-3313. https://doi.org/10.1016/j.tet.2010.03.009

Chernyshev V, Rakitov V, Taranushich V, Blinov V. Acyl and Sulfonyl Derivatives of 3,5-Diamino-1-R-1,2,4-triazoles. Chemistry of Heterocyclic Compounds 2005;41(9):1139-1146. https://doi.org/10.1007/s10593-005-0293-2

Chernyshev V, Kosov A, Gladkov E, Shishkina S, Taranushich V, Desenko S, Shishkin O. Reaction of thiosemicarbazide with n-cyanoguanidine: synthesis of 3,5-diamino-1-thiocarbamoyl-and 3,5-diamino-1-thiazol-2-yl-1,2,4-triazoles. Russian Chemical Bulletin 2006;55(2):338-344. https://doi.org/10.1007/s11172-006-0257-4

Chernyshev V, Rakitov V, Taranushich V, Starikova Z. Molecular and crystal structure of 5-amino-3-(N-p-methylbenzoyl-N-p-toluenesulfonyl)amino-1-phenyl-1,2,4-triazole. Chemistry of Heterocyclic Compounds 2007;43(6):776-780. https://doi.org/10.1007/s10593-007-0125-7

Chernyshev V, Rakitov V, Blinov V, Taranushich V, Starikova Z. Alkylation of acyl and sulfonyl derivatives of 3,5-diamino-1-phenyl-1,2,4-triazole. Chemistry of Heterocyclic Compounds 2009;45(4):436-444. https://doi.org/10.1007/s10593-009-0290-y

Papini P. Gazz Chim Ital 1950;80:100.

Papini P. Gazz Chim Ital 1950;80:850.

Papini P. Gazz Chim Ital 1952;82:735.

Bavley A. Acylaceto guanazols. US Patent 2406654 (1946).

Chebanov V, Sakhno Y, Desenko S, Shishkina S, Shishkin O, Musatov V. Unusual Direction of Cyclocondensation of 1-(4-Chlorophenyl)-3,5-diamino-1,2,4-triazole, Pyruvic Acid, and Aldehydes. Synthesis 2011;2011(07):1120-1124. https://doi.org/10.1055/s-0030-1258468

Tapia I, Alcázar V, Morán J, Grande M. Reaction mechanism between pyruvic acid and aromatic amines.. Bulletin of the Chemical Society of Japan 1990;63(8):2408-2413. https://doi.org/10.1246/bcsj.63.2408

Ghavtadze N, Fröhlich R, Würthwein E. 2 H ‐Pyrrole Derivatives from an Aza‐Nazarov Reaction Cascade Involving Indole as the Neutral Leaving Group . European Journal of Organic Chemistry 2008;2008(21):3656-3667. https://doi.org/10.1002/ejoc.200800384

Abasolo M, Gaozza C, Fernández B. Kinetic study on the anelation of heterocycles. 1 . Quinoxalinone derivatives synthesized by hinsberg reaction . Journal of Heterocyclic Chemistry 1987;24(6):1771-1775. https://doi.org/10.1002/jhet.5570240651

Liu K, Shih B, Lee C. Cyclocondensation of 3-amino-2-iminonaphtho[1,2-d]-thiazole withα-ketocarboxylic acid derivatives: Synthesis of 2-substituted 3-Oxo-3H-naphtho[1′,2′:4,5]thiazolo-[3,2-b][1,2,4]triazines as potential anti-HIV agents. Journal of Heterocyclic Chemistry 1992;29(1):97-101. https://doi.org/10.1002/jhet.5570290116

Groenendaal B, Ruijter E, Orru R. 1-Azadienes in cycloaddition and multicomponent reactions towards N-heterocycles. Chemical Communications 2008;(43):5474. https://doi.org/10.1039/b809206k

Bossert F, Vater W. 1,4-Dihydropyridines—a basis for developing new drugs. Medicinal Research Reviews 1989;9(3):291-324. https://doi.org/10.1002/med.2610090304

Tsuda Y, Mishina T, Araki K, Inui J, Nakamura T. JP Patent 61227584 (1986).

Tsuda Y, Mishina T, Araki K, Inui J, Nakamura T. Eur Patent 19870408 (1987).

Atwal K, Moreland S. Dihydropyrimidine calcium channel blockers 51: bicyclic dihydropyrimidines as potent mimics of dihydropyridines. Bioorganic & Medicinal Chemistry Letters 1991;1(6):291-294. https://doi.org/10.1016/s0960-894x(01)80810-6

Chebanov V, Sakhno Y, Desenko S, Chernenko V, Musatov V, Shishkina S, Shishkin O, Kappe C. Cyclocondensation reactions of 5-aminopyrazoles, pyruvic acids and aldehydes. Multicomponent approaches to pyrazolopyridines and related products. Tetrahedron 2007;63(5):1229-1242. https://doi.org/10.1016/j.tet.2006.11.048

Chebanov V, Sakhno Y, Desenko S. High regioselective ultrasonic-assisted synthesis of 2,7-diaryl-4,7-dihydropyrazolo[1,5-a]pyrimidine-5-carboxylic acids. Ultrasonics Sonochemistry 2012;19(3):707-709. https://doi.org/10.1016/j.ultsonch.2011.08.003

Sakhno Y, Shishkina S, Shishkin O, Musatov V, Vashchenko E, Desenko S, Chebanov V. Diversity oriented heterocyclizations of pyruvic acids, aldehydes and 5-amino-N-aryl-1H-pyrazole-4-carboxamides: catalytic and temperature control of chemoselectivity. Molecular Diversity 2010;14(3):523-531. https://doi.org/10.1007/s11030-010-9226-9

Chebanov V, Kozyryev A, Morozova A, Muravyova E, Murlykina M, Ya S. Proceedings of the 8th International Conference in Chemistry Toulouse-Kiev. 2015.

Gorobets N, Sedash Y, Ostras K, Zaremba O, Shishkina S, Baumer V, Shishkin O, Kovalenko S, Desenko S, Van der Eycken E. Unexpected alternative direction of a Biginelli-like multicomponent reaction with 3-amino-1,2,4-triazole as the urea component. Tetrahedron Letters 2010;51(16):2095-2098. https://doi.org/10.1016/j.tetlet.2010.02.045

El-Hamouly WS. El-Khamry A-MA, Abbas EMH. Ind J Chem 2006;45B:2091.

Svetlik J, Hanus V, Bella J. J Chem Res 1991;1:101.

Svetlik J, Veizerová L, Mayer T, Catarinella M. Monastrol analogs: A synthesis of pyrazolopyridine, benzopyranopyrazolopyridine, and oxygen-bridged azolopyrimidine derivatives and their biological screening. Bioorganic & Medicinal Chemistry Letters 2010;20(14):4073-4076. https://doi.org/10.1016/j.bmcl.2010.05.085

Sve˘tlík J, Veizerová L, Kettmann V. Biginelli-like reaction with dialkyl acetone-1,3-dicarboxylates: a remarkable case of steric control. Tetrahedron Letters 2008;49(21):3520-3523. https://doi.org/10.1016/j.tetlet.2008.03.136

Svĕtlík J, Veizerová L. A Different Role of Meldrum's Acid in the Biginelli Reaction. Helvetica Chimica Acta 2011;94(2):199-205. https://doi.org/10.1002/hlca.201000193

Světlík J, Tureček F, Hanuš V. Formation of oxygen-bridged heterocycles in the hantzsch synthesis with 4-(2-hydroxyphenyl)but-3-en-2-one. J. Chem. Soc., Perkin Trans. 1 1988;(7):2053-2058. https://doi.org/10.1039/p19880002053

Světlík J, Kettmann V. The chameleon-like behaviour of 3-amino-1,2,4-triazole in the Biginelli reaction: unexpected formation of a novel spiroheterocyclic system. Tetrahedron Letters 2011;52(10):1062-1066. https://doi.org/10.1016/j.tetlet.2010.12.051

Murlykina M, Sakhno Y, Desenko S, Konovalova I, Shishkin O, Sysoiev D, Kornet M, Chebanov V. Features of switchable multicomponent heterocyclizations of salicylic aldehydes and 5-aminopyrazoles with pyruvic acids and antimicrobial activity of the reaction products. Tetrahedron 2013;69(44):9261-9269. https://doi.org/10.1016/j.tet.2013.08.055

Chebanov V, Saraev V, Shishkina S, Shishkin O, Musatov V, Desenko S. Controlled Switching of Multicomponent Heterocyclizations of 5-Amino- N -arylpyrazole-4-carboxamides, 1,3-Cyclohexanediones, and Aldehydes . European Journal of Organic Chemistry 2012;2012(28):5515-5524. https://doi.org/10.1002/ejoc.201200669

Muravyova E, Desenko S, Rudenko R, Shishkina S, Shishkin O, Sen’ko Y, Vashchenko E, Chebanov V. Switchable selectivity in multicomponent heterocyclizations of acetoacetamides, aldehydes, and 3-amino-1,2,4-triazoles/5-aminopyrazoles. Tetrahedron 2011;67(48):9389-9400. https://doi.org/10.1016/j.tet.2011.09.138

Downloads

Published

2015-10-27