A New Method for the Synthesis of 2,6-Disubstituted 4(3<i>H</i>)-Pyrimidinones from Benzamidine

Marsura, Alain; Duc, Cuong Luu

doi:10.1055/s-1982-29876

Cited by 12 publications

(3 citation statements)

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“…Following just step II of general procedure 1, with vi (0.63 g, 2.5 mmol) and phenethylamine (0.91 g, 7.5 mmol), 9 was obtained as a colorless oil (0.40 g, 62% yield); R f = 0.3 (10% EtOAc + pet ether). IR (neat): ν max 3086, 3028, 1714, 1649, 1604, 1495, 1453, 1198, 1030, 858, 740 cm –1 ; 1 H NMR (400 MHz, CDCl 3 ) δ 7.37 (d, J = 7.2 Hz, 2H), 7.29–7.17 (m, 8H), 3.99 (dq, J 1 = 7.2 Hz, J 2 = 10.8 Hz, 1H), 3.88 (dq, J 1 = 7.2 Hz, J 2 = 10.8 Hz, 1H), 3.09–3.04 (m, 1H), 3.00–2.91 (m, 2H), 2.86 (d, J = 7.2 Hz, 1H), 2.63–2.58 (m, 1H), 2.43 (d, J = 7.2 Hz, 1H), 0.94 (t, J = 7.2 Hz, 3H); 13 C{ 1 H} NMR (100 MHz, CDCl 3 ): δ 168.1, 139.2, 135.1, 128.7 (2C), 128.3 (2C), 127.8 (2C), 127.7 (2C), 127.3, 126.2, 62.2, 60.6, 47.8, 46.0, 35.8, 13.8.…”

Section: Methodsmentioning

confidence: 99%

A Metal-Free Domino Process for Regioselective Synthesis of 1,2,4-Trisubstituted Pyrroles: Application toward the Formal Synthesis of Ningalin B

et al. 2019

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A new one-pot, transition-metal, acid/base-free domino process is developed for the regioselective synthesis of 1,2,4-trisubstituted pyrroles. The process involves 1,3-dipolar cycloaddition of unsymmetrical azomethine ylide resulting from the thermal C−C bond cleavage of unactivated aziridines with β-bromo-β-nitrostyrene, followed by a cascade of elimination and aromatization reaction sequence to preferentially furnish 1,2,4-trisubstituted pyrroles instead of the expected 1,2,3-trisubstituted pyrroles, in good to excellent yields. Further, the application of the methodology for the formal synthesis of ningalin B is delineated.

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Section: Methodsmentioning

confidence: 99%

A Metal-Free Domino Process for Regioselective Synthesis of 1,2,4-Trisubstituted Pyrroles: Application toward the Formal Synthesis of Ningalin B

et al. 2019

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“…2-Phenyl-3H-pyrimidin-4-ones have been synthesized by the reaction of: i) acetylacetone, acetylacetophenone, and ethyl acetoacetate with amidoximes catalyzed by ruthenium carbon monoxide under a carbon monoxide pressure of 5 kg cm -2 ; 3 ii) ethylacetophenones with benzamidine hydrochloride in the presence of DMF and potassium hydroxide or potassium tert-butoxide; 4 iii) acetylacetone, methylacetonate, and dimethyl malonate with benzamidine; 5 iv) ethyl a-bromocinnamates with benzamidine in the presence of an excess of triethylamine in anhydrous benzene; 6 and v) 3-aminocrotonamide with benzonitrile in methanol and sodium methoxide. 7 2-Phenylpyrimidine-4ones have also been synthesized by the derivatization and chemical transformation of the substituents from other pyrimidines.…”

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confidence: 99%

“…5, [8][9][10] One can observe from the examples cited above that there are only few methods available for the synthesis of 5-or 6-substituted 2-phenyl-3H-pyrimidin-4-ones. In addition, some of these methods are of restricted scope, 3,5 result in low yields, 6,11 or entail a multi-step synthesis. 12 Furthermore, the synthetic potential of 4-alkoxy-1,1,1-trichloroalk-3-ene-2-ones 1a-o as precursors of 2-phenyl-3Hpyrimidin-4-ones has not been tested yet.…”

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confidence: 99%