Reaction of dihalocarbenes with 2-(benzylideneamino)pyridines. Cyclization of 2-(benzylideneamino)pyridinium dihalomethylids to give 2-aryl-3-haloimidazo[1,2-?]pyridines

Khlebnikov, Alexander F.; Kostik, E. I.; Kostikov, R. R.

doi:10.1007/bf00472515

Cited by 7 publications

(3 citation statements)

References 5 publications

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“…Ylides, generated by addition of dichlorocarbene to azines, diazines and its fused derivatives, are well studied [8][9][10][11][12][13][14][15]. These species have been used as synthetic blocks in the preparation of chlorosubstituted indolizines, its heteroatomic and fused derivatives via 1,3-dipolar cycloaddition to various dipolarophiles.…”

Section: Introductionmentioning

confidence: 99%

Formation and reactivity of gem-difluoro-substituted pyridinium ylides: Experimental and DFT investigation

Kobylianskii

Новиков

Khlebnikov

2011

Journal of Fluorine Chemistry

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Section: Introductionmentioning

confidence: 99%

Formation and reactivity of gem-difluoro-substituted pyridinium ylides: Experimental and DFT investigation

Kobylianskii

Новиков

Khlebnikov

2011

Journal of Fluorine Chemistry

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“…Compounds 2h-j were described earlier [12] however oxidative bromination with them was not carried out.…”

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Oxidative bromination of imidazoheterocycle bromohydrates*

Kovalenko

Cherepakha

Kutrov

et al. 2012

Chem Heterocycl Comp

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bromides derivatives in oxidative bromination reactions has been studied. It has been established that reaction products structures and their yields depend on the properties of the substituents in the bicycle and the oxidant concentration.It is known [1,2] that the attack of electrophilic agents predominantly proceeds on the imidazole ring of imidazoheterocycles*. Among such reactions there is considerable interest in bromination because brominesubstituted imidazo[1,2-a]pyridines, imidazo[1,2-a]pyrimidines, and imidazo[2,1-b]thiazoles have found use as physiologically active substances [3] Most frequently bromination of the starting bases is carried out by bromine in chloroform [4], in acetic acid [5] or with the help of such brominating agents as N-bromosuccinimide and N-bromoacetamide in ethanol or carbon tetrachloride [6]. Interesting is the method of synthesis of bromo-substituted imidazoheterocycles by treating bromohydrates of the starting bases with an oxidizing agent. Note that carrying out this type of reaction in dimethyl sulfoxide, the solvent also acts as oxidant [7]. We have used hydrogen peroxide as oxidant in our work on the synthesis of bromo-substituted imidazo[1,2-a]pyridines [8,9] and also sodium nitrite in glacial AcOH (in particular in the synthesis of 5-bromo-6-(bromomethyl)imidazo[2,1-b]thiazole [10]).Earlier [8,11] we have synthesized bromides of imidazo[1,2-a]pyridinium, imidazo[1,2-a]pyrimidinium, and imidazo[2,1-b]thiazolium derivatives by interaction of the corresponding 2-aminoheterocycles with mono-or dihalo ketones. The reaction products were isolated as the salts 1a-g and converted into the dehydrated salts 2a-g. _______ *The term imidazoheterocycles means bicyclic heterosystems, one of the rings of which is imidazole (for example, imidazopyridine, imidazopyrimidine, and imidazothiazole).

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“…This type of transformation was earlier realized for acyclic 2,2,2-trichloroethylamines. 12,13 Scheme 3…”

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confidence: 99%

A Convenient Access to 3-(Trihalomethyl)-3-phenyl-3,4-dihydro-2H-1,4-benzoxazines/thiazines and Chlorinated 3-Phenyl-2,3-dihydro-1,5-benzoxazepines/thiazepines by an Aziridination-Selective-Ring-Opening Sequence

Shinkevich¹,

Новиков²,

Khlebnikov³

2007

Synthesis

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Aziridine ring opening with N-C(1) bond breaking in 1,1-dichloro-1a-phenyl-1a,2-dihydro-1H-azirino[2,1-c][1,4]benzoxazine and -benzothiazine proceeds under the action of hydrohalo acid to give 3-trihalomethyl derivatives of 1,4-benzoxazine and thiazine. When the same compounds react with boron trifluoride etherate, the ring expansion with N-C(1a) bond breaking takes place with formation of 3,4-dichloro-3-phenyl-2,3-dihydro-1,5-benzoxazepine and -1,5-benzothiazepine. These are convenient precursors for the synthesis of 4-substituted 1,5-benzoxazepine and 1,5-benzothiazepine derivatives via reaction with nucleophiles.

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Reaction of dihalocarbenes with 2-(benzylideneamino)pyridines. Cyclization of 2-(benzylideneamino)pyridinium dihalomethylids to give 2-aryl-3-haloimidazo[1,2-?]pyridines

Cited by 7 publications

References 5 publications

Formation and reactivity of gem-difluoro-substituted pyridinium ylides: Experimental and DFT investigation

Formation and reactivity of gem-difluoro-substituted pyridinium ylides: Experimental and DFT investigation

Oxidative bromination of imidazoheterocycle bromohydrates*

A Convenient Access to 3-(Trihalomethyl)-3-phenyl-3,4-dihydro-2H-1,4-benzoxazines/thiazines and Chlorinated 3-Phenyl-2,3-dihydro-1,5-benzoxazepines/thiazepines by an Aziridination-Selective-Ring-Opening Sequence

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Reaction of dihalocarbenes with 2-(benzylideneamino)pyridines. Cyclization of 2-(benzylideneamino)pyridinium dihalomethylids to give 2-aryl-3-haloimidazo[1,2-?]pyridines

Cited by 7 publications

References 5 publications

Formation and reactivity of gem-difluoro-substituted pyridinium ylides: Experimental and DFT investigation

Formation and reactivity of gem-difluoro-substituted pyridinium ylides: Experimental and DFT investigation

Oxidative bromination of imidazoheterocycle bromohydrates*

A Convenient Access to 3-(Trihalomethyl)-3-phenyl-3,4-dihydro-2H-1,4-benz­oxazines/thiazines and Chlorinated 3-Phenyl-2,3-dihydro-1,5-benzoxazepines/thiazepines by an Aziridination-Selective-Ring-Opening Sequence

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A Convenient Access to 3-(Trihalomethyl)-3-phenyl-3,4-dihydro-2H-1,4-benzoxazines/thiazines and Chlorinated 3-Phenyl-2,3-dihydro-1,5-benzoxazepines/thiazepines by an Aziridination-Selective-Ring-Opening Sequence