2,4-Diaminodihydropyridine

Schweiger, Klaus; Zigeuner, G.

doi:10.1007/bf00901825

Cited by 6 publications

(4 citation statements)

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“…Such b-carbon additions accompanied by amine exchange indeed have been observed with compounds of type 7. 24 The present computational results are also nicely corroborated by experimental findings on the related reaction of hydroxylamine with bketo esters. 21,22 Based on the calculations, therefore, preferential formation of 9 and 10, respectively, depending on whether 4-amino-(7) or 4-hydroxypyridinones (8A or 8B) are used as starting materials, can be fully rationalized.…”

Section: Resultssupporting

confidence: 90%

Effect of substituents on the formation of isomeric isoxazolo heterocycles: rationalization by semi-empirical PM3 molecular orbital calculations

Fabian

Schweiger

Weis

1999

J. Phys. Org. Chem.

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The different behavior of 4-amino-vs 4-hydroxypyridinones 7 and 8, respectively, towards hydroxylamine is rationalized with the aid of semi-empirical PM3 molecular orbital calculations including solvent effects. Four different mechanisms leading to either isoxazolo [4,3-c]pyridinones 9 or isoxazolo[4,5-c]pyridinones 10 are considered. Based on computed activation energies reaction of hydroxylamine via its oxygen atom as nucleophile is highly disfavored. For compound 7 a b-carbon addition of NH 2 OH at C-4 of the pyridinone accompanied by amine exchange and ring closure to 9 is by far the most feasible pathway. In contrast to 7, according to both NMR spectroscopy and molecular orbital [semi-empirical PM3 and hybrid density functional/Hartree-Fock (B3LYP/6-31G*)] calculations, 8 exists as a mixture of tautomers 8A (ca 20%) and (Z)-8B (ca 80%). Both tautomers of 8 are predicted to react with hydroxylamine at the hydroxyethylidene carbon atom [(Z)-8B] or acyl functionality (8A) to give hydroxyaminoethylidene compound 38 (oxime 23). Subsequent cyclization of either of these intermediates leads to compound 10.

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Section: Resultssupporting

confidence: 90%

Effect of substituents on the formation of isomeric isoxazolo heterocycles: rationalization by semi-empirical PM3 molecular orbital calculations

Fabian

Schweiger

Weis

1999

J. Phys. Org. Chem.

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“…: 188 °C [11]); the melting points are identical with the reported ones. Compounds 18a is described, the melting point (192 °C) does not correspond very well with the reported one (204 °C) [15] maybe due to the use of different solvents. The preparation of compound 18b is also described, but no melting point is given [15].…”

Section: Methodsmentioning

confidence: 66%

“…Compounds 18a is described, the melting point (192 °C) does not correspond very well with the reported one (204 °C) [15] maybe due to the use of different solvents. The preparation of compound 18b is also described, but no melting point is given [15]. Therefore, we support full data for compounds 18a and 18b.…”

Section: Methodsmentioning

confidence: 66%

“…1 H NMR (CDCl 3 , 400 MHz): δ = 1.00 (t, J = 7.1 Hz, 6H, H-2″), 1.10 (d, J = 6.2 Hz, 3H, H-1′), 1. 15 3 of ethanol via stirring at r.t.. During the reaction, compressed air was passed through the reaction mixture. After 15 d the solvent was evaporated in vacuo and the residue crystallized from chloroform/ethyl acetate.…”

Section: (Rs)-()-4-[[1-(4-chlorobenzyl)-22-dimethyl-1234-tetrahydropyridin-4-yliden]amino]-nn-dimethylpentanamin (10 G C 23 H 36 Cln 3 )mentioning

confidence: 99%

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Modifications and hybrids of 1,2,3,4-tetrahydropyridinium salts and their antiprotozoal potencies

et al. 2021

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The antiprotozoal activity of 1-benzyltetrahydropyridin-4-yliden iminium salts is reported. This paper describes the preparation of a series of analogs from dihydropyridines or dihydrothiopyrans as educts. The new compounds were investigated for their activity against Plasmodium falciparum NF54, a causative organism of Malaria tropica and Trypanosoma brucei rhodesiense, the causative organism of Human African Trypanosomiasis (sleeping sickness). Several structure–activity relationships were detected. Both the substituents in ring positions 1 and 4 of the tetrahydropyridinium moiety had a strong impact on the antiprotozoal activities as well as on the cytotoxicity of compounds against L-6 cells (rat skeletal myoblasts). All new compounds were characterized using FT-IR spectroscopy, HRMS, and NMR spectroscopy. Graphic abstract

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