Studies in Imidazoles. I. Imidazo(b)quinoxalines<sup>1,2</sup>

Schipper, Edgar; Day, Allan R.

doi:10.1021/ja01156a054

Cited by 19 publications

(4 citation statements)

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“…Several examples have been described in the literature on the hydrolysis of 2-aminoquinoxalines leading to quinoxalinones. Thus, the 2,3-diaminoquinoxaline is hydrolyzed by hydrochloric acid (2.5M) at 100 °C, for 5 minutes to give 3-aminoquinoxalin-2-one [68]. In the same way, the treatment of 2-amino-3-phenylquinoxaline by nitric acid, give 3-phenylquinoxalin-2-one with an excellent performance [69].…”

Section: From Quinoxaline Intermediatesmentioning

confidence: 99%

Synthetic Methods and Exploring Biological Potential of Various Substituted Quinoxalin-2-one Derivatives

2016

European Reviews of Chemical Research

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Substituted quinoxaline have considerable interest in chemistry, biology and pharmacology. Quinoxaline derivatives are capable with variety of biological activities and possess different biological activities, of which the most potent are anti-microbial, analgesic and anti-inflammatory activities. It facilitated the researchers to develop various methods for their synthesis and their applications. In this review represented different methods of synthesis, reactivity and various biological activities of quinoxaline derivatives.Keywords: Quinoxaline, reactivity, biological activities, synthetic methods. IntroductionQuinoxaline and its derivatives are important nitrogen containing heterocyclic compounds of various biologically properties. Quinoxaline and its derivatives are mostly of synthetic origin. Substituted quinoxalines are an important class of benzoheterocycles, which constitute the building blocks of wide range of pharmacologically active compounds having antibacterial [1][2][3][4] [15] activities. The quinoxaline is described as a bioisoster of quinoline, naphthalene, benzothiophene and other aromatic rings such as pyridine and pyrazine. Because of the similarity between some antitubercular drugs and quinoxaline, as well as the presence of the quinoxaline moiety in some broad spectrum antibiotics, it was hoped that quinoxaline analogs would exhibit antitubercular activity [16]. The quinoxaline antibiotics are agents of bicyclic desipeptide antibiotic that have been reported activity against gram-positive bacteria and certain tumors and to inhibit RNA synthesis [17]. Quinoxaline has also been used in reactive dyes and pigments, azo dyes, fluroscein dyes and it also forms a part of certain antibiotics. Quinoxaline m.p. 29-30ºC and is miscible with water. It is weakly basic (pka 0.56) and thus considerably weaker base than the isomeric diazonapthalenes namely cinnoline (pka 2.42), pthalizine (pka 3.47) or quinazoline (pka 1.95). 2-Hydroxy-but not 2-amino quinoxaline exist in tautomeric forms.

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Section: From Quinoxaline Intermediatesmentioning

confidence: 99%

Synthetic Methods and Exploring Biological Potential of Various Substituted Quinoxalin-2-one Derivatives

2016

European Reviews of Chemical Research

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“…22 The parent lH-imidazo [4,5-blquinoxaline (54) is amphoteric, forming stable sodium salts, hydrochlorides, and picrates. Apparently fusion of the imidazole ring onto the quinoxaline nucleus results in only a small contribution to the ultraviolet spectrum.…”

Section: Etmentioning

confidence: 99%

“…Alkali treatment of compound 65 gives the 1,3-unsubstituted product 59 4. The 1-methyl-2-iminoquinoxaline 66 reacts with triethyl orthoformate to give 4-methylimidazo[4,5-b]quinoxaline (67), and the 4methyl-2-0x0 derivative 68 is produced by reaction of 66 with urea 22. The 1-methyl-2-iminoquinoxaline 66 reacts with triethyl orthoformate to give 4-methylimidazo[4,5-b]quinoxaline (67), and the 4methyl-2-0x0 derivative 68 is produced by reaction of 66 with urea 22.…”

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confidence: 99%

Imidazoquinoxalines

1979

Chemistry of Heterocyclic Compounds: A Series of Monographs

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“…The sequence constitutes a ring synthesis of the benzimidazole nucleus from the substituted 1,2-benzenediamine. The cyclization reactions were carried out using excess of the required ortho ester. , In some cases, the reaction could be catalyzed by p- TsOH; however, in the more demanding cyclizations using (EtO) 3 CCH 3 and (EtO) 3 CPh, the use of 1 equiv of hydrochloric acid proved necessary. Basicification and extractive workup then provided the benzimidazole free bases.…”

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confidence: 99%

Aromatic Amination/Imination Approach to Chiral Benzimidazoles

2002

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The powerful Buchwald-Hartwig amination was utilized for the construction of the benzimidazole nucleus with the substituted nitrogen atom bearing a chiral substituent. A successive amination/imination was followed by an acid-catalyzed ring closure step to give the benzimidazole ring. The products were deprotonated and acylated at the C2 position and could be alkylated on nitrogen to give chiral benzimidazolium salts.

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Studies in Imidazoles. I. Imidazo(b)quinoxalines^1,2

Cited by 19 publications

References 2 publications

Synthetic Methods and Exploring Biological Potential of Various Substituted Quinoxalin-2-one Derivatives

Synthetic Methods and Exploring Biological Potential of Various Substituted Quinoxalin-2-one Derivatives

Imidazoquinoxalines

Aromatic Amination/Imination Approach to Chiral Benzimidazoles

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Studies in Imidazoles. I. Imidazo(b)quinoxalines1,2

Cited by 19 publications

References 2 publications

Synthetic Methods and Exploring Biological Potential of Various Substituted Quinoxalin-2-one Derivatives

Synthetic Methods and Exploring Biological Potential of Various Substituted Quinoxalin-2-one Derivatives

Imidazoquinoxalines

Aromatic Amination/Imination Approach to Chiral Benzimidazoles

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Studies in Imidazoles. I. Imidazo(b)quinoxalines^1,2