Novel halogenated imidazoles. Chloroimidazoles

Lutz, A; Delorenzo, Sylvio

doi:10.1002/jhet.5570040318

Cited by 38 publications

(37 citation statements)

References 4 publications

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“…4,5-Dichloroimidazole, commercially available from Fluka, Neu-Ulm, Germany, was used after recrystallization from hot water (colorless small prisms) [3] for both experiments, 35 C1 NQR and X-ray diffraction.…”

Section: Methodsmentioning

confidence: 99%

NQR and Crystal Structure of 4,5-Dichloroimidazole, C₃H₂N₂Cl₂

Dou

Weiß

1992

Zeitschrift Für Naturforschung A

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The two line 35 C1 NQR spectrum of 4,5-dichloroimidazole was measured in the temperature range 77^ T/K ^389. The temperature dependence of the NQR frequencies conforms with the Bayer model and no phase transition is indicated in the curves v( 35 Cl)= f(T). The compound crystallizes at room temperature with the tetragonal space group D4-P41212, Z = 8 molecules per unit cell; at 295 K: a = 684.2(5) pm, c = 2414.0(20) pm. The relations between the crystal structure and the NQR spectrum are discussed.

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Section: Methodsmentioning

confidence: 99%

NQR and Crystal Structure of 4,5-Dichloroimidazole, C₃H₂N₂Cl₂

Dou

Weiß

1992

Zeitschrift Für Naturforschung A

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“…The chlorination of imidazole with NaOCl does not stop at the formation of 4(5)-chloroimidazole (68) but goes further and leads to 4,5-dichloro-(69) and 2,4,5-trichloroimidazoles and (70) with yields of 77 and 9% respectively [33]. Since the dichloro and trichloro derivatives are not reduced by Na 2 SO 3 to chloroimidazole 68 the latter was obtained through the bromo-substituted imidazoles.…”

Section: Chlorination Of Imidazolesmentioning

confidence: 98%

“…The bromination of imidazole by bromine [33,[61][62][63], NBS [61,64], and 2,4,4,6-tetrabromohexa-2,5-diene (TBD) [65] leads to various mixtures of 4(5)-bromo-72, 4,5-dibromo-122, and 2,4,5-tribromoimidazole 71. The yield of the tribromide 71 during the bromination of imidazole with bromine in glacial acetic acid in the presence of AcONa amounts to 78-80% [62].…”

Section: By Bromination Of Imidazolesmentioning

confidence: 99%

“…The same product was obtained with a yield of about 90% by treating bromoimidazole 72 with conc. HCl at 150°C, but in this case it contained about 8% of the initial compound 72 as impurity [33]. The chlorination of 2-substituted imidazoles 75 by the action of PCl 5 [34], chlorine [35], NaOCl [33,36,37], and N-chlorosuccinimide (NCS) [38] leads to the corresponding 4,5-dichloroimidazoles 76 (yields 18-93%).…”

Section: Chlorination Of Imidazolesmentioning

confidence: 99%

“…The 4,5-dibromoimidazoles 138 were synthesized with yields of 52-92% by bromination of the 2-substituted imidazoles 75 with bromine [33,36,67], NBS [38,64], and PBr 5 [34,49]. Reduction of the products (with R = Alk) by Na 2 SO 3 gave 2-84% yields of the 2-alkyl-4(5)-bromoimidazoles 139 [67].…”

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confidence: 99%

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Methods for the synthesis of haloimidazoles (review)

Александрова

Кравченко

Кочергин³

2011

Chem Heterocycl Comp

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Published information on methods for the synthesis of haloimidazoles is summarized and classified.Haloimidazoles form an important group of compounds used as synthons for the production of various derivatives of imidazole and condensed heterocyclic systems based on imidazole, including those with a nodal nitrogen atom. Some derivatives of haloimidazoles have high biological activity and have found use as drugs for the treatment of hypertonia [1] and also as chemical agents for the protection of plants [2].Papers on the synthesis of haloimidazoles, mostly published before the middle of the twentieth century, are found in the monograph [3] and in the reviews [4][5][6]. However, the most important researches on the development of methods for the production of these compounds were executed in the last 55-60 years. This review is devoted to discussion of these methods. SYNTHESIS OF FLUOROIMIDAZOLESAs will be described below, the direct halogenation of imidazoles by the respective halogens or halogenreleasing reagents (sodium hypochlorite, N-halosuccinimides, PCl 5 , etc.) used for the production of bromo-, iodo-, and chloroimidazoles is not used for the synthesis of fluoroimidazoles.The chief method for the synthesis of these compounds is the photochemical cleavage of imidazolediazonium fluoroborates.The method was first proposed for the transformation of aromatic amines 1 into the fluoroarenes 3 through the diazonium salts 2 [7,8]. Here it was established that salts of type 2 are more stable compounds than salts of the ArN 2 + X − type, where X is a halogen.

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