Synthesis of 4-aminopyrimidines from 1,2,4-oxadiazoles. Part 4. A novel heterocyclic rearrangement

Formation of 4-hydroximinohexahydropyrimidines from 3-(2-aminoethyl)-4,5-dihydro-1,2,4-oxadiazoles

Dezsö Korbonits, Erzsébet Tóbiás-Héja, Kalman Simon, György Krámer, P. Kolonits

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Abstract

The 4,5-dihydro derivatives of 3-(2-aminoethyl)-5-substituted-1,2,4- oxadiazoles 1 have been prepared. These derivatives 8a-d rearrange readily, but in contrast to compounds 1, not to pyrazoles, but to 2-aryl-1-benzyl-4- hydroximinohexahydropyrimidines 9a-d. Studies on the mechanism of the 1 → 2 azole-azole, and the novel 8 → 9 azole-azine, rearrangements revealed that the site of the side chain nitrogen attack is controlled by the presence or absence of a delocalized π-electron system in the starting azole ring. Compound 9a and benzaldehyde gave cis- and trans-6-benzyl-3,5-diphenyl-5,6,7,8- tetrahydro-3H-[1,2,4]-oxadiazolo[4,3-c]pyrimidines 16 and 17, respectively. The structures of 9a, 16 and 17 were confirmed by X-ray crystallography.

Original languageEnglish
Pages (from-to)3069-3074
Number of pages6
JournalJournal of the Chemical Society, Perkin Transactions 1
Issue number22
Publication statusPublished - 1992

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Oxadiazoles
Azoles
Pyrazoles
Derivatives
Pyrimidines
X ray crystallography
Nitrogen
4-aminopyrimidine
Electrons

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

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title = "Synthesis of 4-aminopyrimidines from 1,2,4-oxadiazoles. Part 4. A novel heterocyclic rearrangement: Formation of 4-hydroximinohexahydropyrimidines from 3-(2-aminoethyl)-4,5-dihydro-1,2,4-oxadiazoles",
abstract = "The 4,5-dihydro derivatives of 3-(2-aminoethyl)-5-substituted-1,2,4- oxadiazoles 1 have been prepared. These derivatives 8a-d rearrange readily, but in contrast to compounds 1, not to pyrazoles, but to 2-aryl-1-benzyl-4- hydroximinohexahydropyrimidines 9a-d. Studies on the mechanism of the 1 → 2 azole-azole, and the novel 8 → 9 azole-azine, rearrangements revealed that the site of the side chain nitrogen attack is controlled by the presence or absence of a delocalized π-electron system in the starting azole ring. Compound 9a and benzaldehyde gave cis- and trans-6-benzyl-3,5-diphenyl-5,6,7,8- tetrahydro-3H-[1,2,4]-oxadiazolo[4,3-c]pyrimidines 16 and 17, respectively. The structures of 9a, 16 and 17 were confirmed by X-ray crystallography.",
author = "Dezs{\"o} Korbonits and Erzs{\'e}bet T{\'o}bi{\'a}s-H{\'e}ja and Kalman Simon and Gy{\"o}rgy Kr{\'a}mer and P. Kolonits",
year = "1992",
language = "English",
pages = "3069--3074",
journal = "Journal of the Chemical Society, Perkin Transactions 1",
issn = "1472-7781",
publisher = "Chemical Society",
number = "22",

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TY - JOUR

T1 - Synthesis of 4-aminopyrimidines from 1,2,4-oxadiazoles. Part 4. A novel heterocyclic rearrangement

T2 - Formation of 4-hydroximinohexahydropyrimidines from 3-(2-aminoethyl)-4,5-dihydro-1,2,4-oxadiazoles

AU - Korbonits, Dezsö

AU - Tóbiás-Héja, Erzsébet

AU - Simon, Kalman

AU - Krámer, György

AU - Kolonits, P.

PY - 1992

Y1 - 1992

N2 - The 4,5-dihydro derivatives of 3-(2-aminoethyl)-5-substituted-1,2,4- oxadiazoles 1 have been prepared. These derivatives 8a-d rearrange readily, but in contrast to compounds 1, not to pyrazoles, but to 2-aryl-1-benzyl-4- hydroximinohexahydropyrimidines 9a-d. Studies on the mechanism of the 1 → 2 azole-azole, and the novel 8 → 9 azole-azine, rearrangements revealed that the site of the side chain nitrogen attack is controlled by the presence or absence of a delocalized π-electron system in the starting azole ring. Compound 9a and benzaldehyde gave cis- and trans-6-benzyl-3,5-diphenyl-5,6,7,8- tetrahydro-3H-[1,2,4]-oxadiazolo[4,3-c]pyrimidines 16 and 17, respectively. The structures of 9a, 16 and 17 were confirmed by X-ray crystallography.

AB - The 4,5-dihydro derivatives of 3-(2-aminoethyl)-5-substituted-1,2,4- oxadiazoles 1 have been prepared. These derivatives 8a-d rearrange readily, but in contrast to compounds 1, not to pyrazoles, but to 2-aryl-1-benzyl-4- hydroximinohexahydropyrimidines 9a-d. Studies on the mechanism of the 1 → 2 azole-azole, and the novel 8 → 9 azole-azine, rearrangements revealed that the site of the side chain nitrogen attack is controlled by the presence or absence of a delocalized π-electron system in the starting azole ring. Compound 9a and benzaldehyde gave cis- and trans-6-benzyl-3,5-diphenyl-5,6,7,8- tetrahydro-3H-[1,2,4]-oxadiazolo[4,3-c]pyrimidines 16 and 17, respectively. The structures of 9a, 16 and 17 were confirmed by X-ray crystallography.

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