NMR Spectra of indolizines and their ? complexes

Бабаев, Е. В.; Torocheshnikov, V. N.; Bobrovskii, S. I.

doi:10.1007/bf01165054

Cited by 7 publications

(6 citation statements)

References 6 publications

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“…This downfield shift can be clearly explained by a " peri -effect" caused by magnetic anisotropy of the 5-formyl group located at the peri -position with respect to proton H 3 . Earlier an analogous effect was observed for 1-COR-, 3-COR-, and 8-COR-substituted indolizines, where the corresponding signals of protons located at the peri -positions (H 8 , H 5 and H 1 respectively) underwent a downfield shift, see review [9]. …”

Section: Resultssupporting

confidence: 57%

An Improved Synthesis of Some 5-Substituted Indolizines Using Regiospecific Lithiation

Кузнецов¹,

Буш²,

Рыбаков³

et al. 2005

Molecules

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Various 2-substituted indolizines can be directly and selectively lithiated in the 5 position and subsequent reactions with different electrophiles lead to some novel classes of indolizines. In particular, previously unknown 5-formyl- and 5-iodoindolizine have been prepared by this way and the molecular structure of 5-formyl-2-phenylindolizine was confirmed by X-Ray analysis. The reactivity of the 5-CHO- and 5-COPh groups toward some nucleophiles has been examined, and some additional classes of derivatives (oximes and alcohols) have been obtained. The possibility of Suzuki cross-coupling of 5-iodoindolizines and boronic acids was proven.

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Section: Resultssupporting

confidence: 57%

An Improved Synthesis of Some 5-Substituted Indolizines Using Regiospecific Lithiation

Кузнецов¹,

Буш²,

Рыбаков³

et al. 2005

Molecules

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“…The unique ability of 6(8)-indolizines to react with nucleophiles has still attracted very little attention. There are only few works devoted to the influence of substituents on the reactivity of indolizines performed by Hückel, PPP, and semiempirical CNDO 3 and MNDO methods.…”

Section: Introductionmentioning

confidence: 99%

On the Alternation Effect in Substituted Indolizines and Their Aza-analogs

1997

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The SINDO1 method is used to calculate charge distribution and total energies in the series of isomeric nitro- and methoxy-substituted indolizines, azaindolizines, and N-methylazaindolizinium cations. The influence of donor and acceptor substituents on the total energy and charges may be treated according to the simple alternation rule. In the series of isomers (substituted or azaindolizines) the lower energies are observed for those molecules, where acceptor substituents are arranged consonant to the polarity of the chain N-C(5)-C(6)-C(7)-C(8)-C(9)-C(1)-C(2)-C(3) of the indolizine. The results are used to treat known peculiarities of ring opening/transformation of indolizine and its aza-derivatives. It is proved that the energies of C(3) and C(5) adducts of isomeric azaindolizines with hydroxyl anion follow the same alternation pattern.

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“…This effect was observed for other 5-acyl indolizines (formyl- and benzoyl derivatives [ 11 ]). Furthermore, 3- and 8-acyl indolizines behaved similarly [ 14 ] with the influence on peri -positions H-5 or H-1. Thus, indolizyl lithium derivatives reacted with succinic or phtalic anhydride, forming previously unknown ketoacids 2 and 3 .…”

Section: Resultsmentioning

confidence: 99%

“…In the 1 H-NMR spectrum, there was a singlet of double intensity of H-3 at 5.8 ppm, while the rest of the signals were shifted downfield. The literature data of the spectra of 1- and 3-CH 2 -indolizyl cations [ 14 , 15 , 16 ] indicate that the position of a singlet of the CH 2 group at δ > 5 ppm is clear proof of protonation at position 3. Since the protonated atom C-3 is excluded from the π-excessive heterocyclic system, its subsequent acylation becomes impossible.…”

Section: Resultsmentioning

confidence: 99%