Heterocyclic Ketene Aminals

Huang, Zhi‐Tang; Hunag, Zhi-Tang; Wan, Meixiang

doi:10.3987/rev-93-sr7

Cited by 117 publications

(80 citation statements)

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“…[7,12] It is noteworthy that ketene aminals, including cyclic imidazolidines, which are analogues of 1, are known to be highly reactive compounds, attracting the attention of investigators as convenient precursors for syntheses of fused heterocyclic systems. Syntheses and reactions of these compounds are discussed in detail in reviews, [16,17] and in more recent works by Huang's group. In contrast, no data on the reactivity of N-hydroxyketene aminals are available in the literature.…”

Section: Introductionmentioning

confidence: 99%

A New Class of Enehydroxylamino Ketones − (R)‐2‐(1‐Hydroxy‐4,4,5,5‐tetraalkylimidazolidin‐2‐ylidene)ethanones: Synthesis and Reactions

et al. 2004

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Three approaches to the synthesis of (R)‐2‐(1‐hydroxy‐4,4,5,5‐tetraalkylimidazolidin‐2‐ylidene)ethanones 1 are described: (a) condensation of 1,2‐bishydroxylamines with β‐ketoaldehyde synthons, (b) treatment of metallated 1‐hydroxy‐2‐methyl‐4,5‐dihydroimidazoles with esters, and (c) 1,3‐dipolar cycloaddition between 1‐hydroxy‐4,5‐dihydroimidazole‐3‐oxide and DMAD. The reactivity of 1 with electrophiles has been studied. The exocyclic methylene (enamine) carbon atom is shown to be the major site of electrophilic attack. Synthesized chloro‐substituted 1‐hydroxy‐2‐acetylideneimidazolidines react with sodium cyanide to form the corresponding nitriles. Oxidation of these nitriles occurs with formation of persistent vinyl nitroxides, which are of interest as potential paramagnetic ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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Section: Introductionmentioning

confidence: 99%

A New Class of Enehydroxylamino Ketones − (R)‐2‐(1‐Hydroxy‐4,4,5,5‐tetraalkylimidazolidin‐2‐ylidene)ethanones: Synthesis and Reactions

et al. 2004

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“…Thus, the synthesis and reactions of heterocyclic ketene aminals have attracted much attention [1]. The reactions of heterocyclic ketene aminals with 1,3-dipolar reagents, such as azides [2][3][4][5][6][7], nitrile imines [8,9], benzonitrile oxide [10,11] or its precursor [12], have been reported.…”

Section: Introductionmentioning

confidence: 99%

The reaction of aroyl-substituted heterocyclic ketene aminals with aryl azides

Liu

Wang

et al. 2000

Heteroatom Chem.

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“…Derivatives of imidazolidine (CXIX), which can exist in the form of both ketene aminal and amidine, are 1,3-binucleophiles and have often been used in the synthesis of N-bridged heterocycles [155]. Their reactions with ot,[3-unsaturated ketones and aldehydes [156][157][158][159][160] give 1,2,3,7-tetrahydroimidazo[l,2-a]pyridines CXX or 1,2,3,5,6,7-hexahydroimidazo[l,2-a]pyridines CXXI, and with aromatic aldehydes [158] they form imidazopyridones CXXII.…”

Section: Syntheses Based On Imidazole Derivativesmentioning

confidence: 99%

Synthesis of 2,3-dihydroimidazo[1,2-a]-pyridines and their salts. (review)

Suloeva¹,

Yure²,

Gudriniece³

1999

Chem Heterocycl Compd

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In the present review the published data on the nomenclature, structure, and synthesis qr 2, 3-dihydroimidazo[1,2-a] [36][37][38][39][40][41][42], while 3-oxoimidazo[l,2-a]pyridines are used as starting materials in the synthesis of N-(2-pyridyl)-c~-amino acids and their esters [43].Several reviews [44-47] on imidazo[1,2-a]pyridines have also described their 2,3-dihydro derivatives. However, both the methods and the properties of these compounds have been covered inadequately. The present review is devoted to the nomenclature, structure, and methods of synthesis of 2,3-dihydroimidazo[l,2-a]pyridines A and their salts B. Compounds containing oxo group at positions 2 and 3 are also included.

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Heterocyclic Ketene Aminals

Cited by 117 publications

References 0 publications

A New Class of Enehydroxylamino Ketones − (R)‐2‐(1‐Hydroxy‐4,4,5,5‐tetraalkylimidazolidin‐2‐ylidene)ethanones: Synthesis and Reactions

A New Class of Enehydroxylamino Ketones − (R)‐2‐(1‐Hydroxy‐4,4,5,5‐tetraalkylimidazolidin‐2‐ylidene)ethanones: Synthesis and Reactions

The reaction of aroyl-substituted heterocyclic ketene aminals with aryl azides

Synthesis of 2,3-dihydroimidazo[1,2-a]-pyridines and their salts. (review)

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