Electrophilic substitution of imidazo[2,1-b]thiazoles

O'Daly, M. Anne; Hopkinson, C. P.; Meakins, G. D.; Raybould, Amanda J.

doi:10.1039/p19910000855

Cited by 11 publications

(7 citation statements)

References 7 publications

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“…The importance of studying this class of heterocycle lead, in recent years, researchers to explore the incorporation of different functional groups to imidazo[2,1‐ b ]thiazole unit. More specifically, these transformations comprehend halogenation, nitrosation, phosphorylation, arylation and chalcogenation reactions…”

Section: Introductionmentioning

confidence: 99%

Copper‐Catalyzed Selective Synthesis of 5‐Selanyl‐imidazo[2,1‐b]thiazoles

et al. 2017

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We describe a selective and direct method to synthesize a wide variety of 5-selanyl-imidazo[2,1-b]thiazoles by copper(I)-catalyzed reaction of imidazo[2,1-b]thiazoles with diorganyl diselenides. The reactions were carried out in DMSO at 90 8C in air. The methodology was tolerant to differently substituted diorganyl diselenides containing electron-deficient, electronrich, and bulky groups. Still, various imidazo[2,1-b]thiazoles were used and furnishing the expected products in good to excellent yields. All the products were selectively coupled at 5position of the imidazo[2,1-b]thiazole and no regioisomers were detected.[a] K.

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Section: Introductionmentioning

confidence: 99%

Copper‐Catalyzed Selective Synthesis of 5‐Selanyl‐imidazo[2,1‐b]thiazoles

et al. 2017

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“…The course of oxidative bromination of imidazo[2,1-b]thiazole derivatives 5a-d and structures of the products obtained 6a-d depend on the nature of substituents on the starting compounds [8][9][10][11]14]. Thus, bromination of compounds 5a-c with a methyl group in position 3 or 6 proceeds with 30% H 2 O 2 at 10-15°C with yields of ~70%.…”

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confidence: 99%

“…Thus, bromination of compounds 5a-c with a methyl group in position 3 or 6 proceeds with 30% H 2 O 2 at 10-15°C with yields of ~70%. Structures of the obtained products correspond to 5-bromo-6-methylimidazo[2,1-b]thiazole (6a) and 5-bromo-3,6-dimethylimidazo[2,1-b]thiazole (6b) which have been synthesized earlier by other methods [14]. In the case of bromide 5c, 5-bromo-6-bromomethyl-3-methylimidazo[2,1-b]thiazole (6c) should be separated immediately as it appeared because of the formation of a solid precipitate which prevented the reaction in the whole volume.…”

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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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“…10 Consequently, derivatives are synthesized by substitutions of previously known compounds. 11 These considerations as well as our strong background in heterocyclic chemistry 12 led us to develop an alternative approach to build these systems. In previous papers, 12a,c we described the versatility of cationic diazadienes as stable synthons for the preparation of various monocycles.…”

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A Facile Access to Imidazo[2,1-b]thiazole and Thiazolo[3,2-a]pyrimidine Derivatives

Landreau¹,

Deniaud²,

Reliquet³

et al. 2001

Synthesis

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A Facile Access to Imidazo[2,1-b]thiazole and Thiazolo[3,2-a]pyrimidine Derivatives A F a c i l e A c c e s s t o I m i d a z o [ 2 , 1 -b ] t h i a z o l e a n d T h i a z o l o [ 3 , 2 -a ] p y r i m i d i n e D e r i v a t i v e sAbstract: A new and efficient method for the synthesis of 2,3-dihydroimidazo[2,1-b]thiazoles 3, 2,3-dihydro-5H-thiazolo[3,2-a]pyrimidin-5-ones 4 and 2,3-dihydro-5H-thiazolo[3,2-a]pyrimidines 5 has been developed. The reactions of N¢-(4,5-dihydrothiazol-2-yl)-N,N-dimethylamidines 1 with a-halogenoketones, acid chlorides or acrylic dienophiles were performed, leading to the title products.

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Electrophilic substitution of imidazo[2,1-b]thiazoles

Cited by 11 publications

References 7 publications

Copper‐Catalyzed Selective Synthesis of 5‐Selanyl‐imidazo[2,1‐b]thiazoles

Copper‐Catalyzed Selective Synthesis of 5‐Selanyl‐imidazo[2,1‐b]thiazoles

Oxidative bromination of imidazoheterocycle bromohydrates*

A Facile Access to Imidazo[2,1-b]thiazole and Thiazolo[3,2-a]pyrimidine Derivatives

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