Substituent effects in the ring-chain tautomerism of 1-alkyl-3-arylnaphth- [1,2-e][1,3]oxazines

Diána Tóth, I. Szatmári, F. Fülöp

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

New 1-(1-aminoalkyl)-2-naphthols 8-11 have been synthesised by the condensation of 2-naphthol with aliphatic aldehydes in the presence of ammonia, followed by acidic hydrolysis. The condensation of 7-11 with substituted benzaldehydes after microwave irradiation led to 1-alkyl-3-aryl-2,3-dihydro-1H- naphth[1,2-e][1,3]oxazines, which proved to be three-component (r t-o-rc) tautomeric mixtures in CDCl3 at 300 K. The electronic effects of the 1-alkyl and 3-aryl groups on the tautomeric ratios could be determined for both the ringtrans-chain and the ring cis-chain equilibria with the aid of two-variant linear equations. A significant difference was found between the coefficients of the Meyer parameter Va, which characterises the volume of the portion of the alkyl substituent within 0.3 nm of the reaction centre, for ringtrans-chain and ringcis-chain equilibria, and this is explained in terms of the stereoelectronic effect caused by the alkyl substituent at position 1.

Original languageEnglish
Pages (from-to)4664-4669
Number of pages6
JournalEuropean Journal of Organic Chemistry
Issue number20
DOIs
Publication statusPublished - Oct 13 2006

Fingerprint

Oxazines
Condensation
Benzaldehydes
Microwave irradiation
Microwaves
Linear equations
Ammonia
Aldehydes
Hydrolysis
2-naphthol
oxazine 1

Keywords

  • Aminonaphthols
  • Betti bases
  • Naphthoxazines
  • Ring-chain tautomerism
  • Substituent effects

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

Substituent effects in the ring-chain tautomerism of 1-alkyl-3-arylnaphth- [1,2-e][1,3]oxazines. / Tóth, Diána; Szatmári, I.; Fülöp, F.

In: European Journal of Organic Chemistry, No. 20, 13.10.2006, p. 4664-4669.

Research output: Contribution to journalArticle

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AU - Fülöp, F.

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N2 - New 1-(1-aminoalkyl)-2-naphthols 8-11 have been synthesised by the condensation of 2-naphthol with aliphatic aldehydes in the presence of ammonia, followed by acidic hydrolysis. The condensation of 7-11 with substituted benzaldehydes after microwave irradiation led to 1-alkyl-3-aryl-2,3-dihydro-1H- naphth[1,2-e][1,3]oxazines, which proved to be three-component (r t-o-rc) tautomeric mixtures in CDCl3 at 300 K. The electronic effects of the 1-alkyl and 3-aryl groups on the tautomeric ratios could be determined for both the ringtrans-chain and the ring cis-chain equilibria with the aid of two-variant linear equations. A significant difference was found between the coefficients of the Meyer parameter Va, which characterises the volume of the portion of the alkyl substituent within 0.3 nm of the reaction centre, for ringtrans-chain and ringcis-chain equilibria, and this is explained in terms of the stereoelectronic effect caused by the alkyl substituent at position 1.

AB - New 1-(1-aminoalkyl)-2-naphthols 8-11 have been synthesised by the condensation of 2-naphthol with aliphatic aldehydes in the presence of ammonia, followed by acidic hydrolysis. The condensation of 7-11 with substituted benzaldehydes after microwave irradiation led to 1-alkyl-3-aryl-2,3-dihydro-1H- naphth[1,2-e][1,3]oxazines, which proved to be three-component (r t-o-rc) tautomeric mixtures in CDCl3 at 300 K. The electronic effects of the 1-alkyl and 3-aryl groups on the tautomeric ratios could be determined for both the ringtrans-chain and the ring cis-chain equilibria with the aid of two-variant linear equations. A significant difference was found between the coefficients of the Meyer parameter Va, which characterises the volume of the portion of the alkyl substituent within 0.3 nm of the reaction centre, for ringtrans-chain and ringcis-chain equilibria, and this is explained in terms of the stereoelectronic effect caused by the alkyl substituent at position 1.

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