Heterocycles. 167. Telesubstitution and other transformations of imidazo[1,2-a]- and s-triazolo[4,3-a]pyrazines

Bradac, Jernej; FUREK, Z.; Janezic, Dasa; MOLAN, S.; Smerkolj, Igor; Stanovnik, B.; Tišler, M.; Vercek, B.

doi:10.1021/jo00862a005

Cited by 41 publications

(23 citation statements)

References 2 publications

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“…Previously reported methods 14 using DMF as a solvent proved to be low yielding, but with methanol as solvent, the product was isolated in 98% yield. However, all subsequent attempts to functionalise the imidazo[1,2- a ]pyrazine core via bromination 14,15 gave extremely poor yields and inseparable mixtures of dibrominated regioisomers. Furthermore, these could not be further transformed using telesubstitution with ammonia, 15,16 to give 8-amino imidazo[1,2- a ]pyrazines as planned.…”

Section: Resultsmentioning

confidence: 99%

2- and 3-substituted imidazo[1,2-a]pyrazines as inhibitors of bacterial type IV secretion

Sayer¹,

Wallden

Pesnot³

et al. 2014

Bioorganic & Medicinal Chemistry

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Section: Resultsmentioning

confidence: 99%

2- and 3-substituted imidazo[1,2-a]pyrazines as inhibitors of bacterial type IV secretion

Sayer¹,

Wallden

Pesnot³

et al. 2014

Bioorganic & Medicinal Chemistry

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“…Amide 1 (2.0 g, 18 mmol; prepared as described [17]) was dissolved in dry DMF (50 ml). Amide 1 (2.0 g, 18 mmol; prepared as described [17]) was dissolved in dry DMF (50 ml).…”

Section: Experimental Partmentioning

confidence: 99%

Evaluation of Novel Third-Strand Bases for the Recognition of a C⋅G Base Pair in the Parallel DNA Triple-Helical Binding Motif

Prévot

Leumann

2002

HCA

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We describe the synthesis and the incorporation into oligonucleotides of the novel nucleoside building blocks 9, 10, and 16, carrying purine-like double H-bond-acceptor bases. These base-modified nucleosides were conceived to recognize selectively a cytosine ¥ guanine (C ¥ G) inversion site within a homopurine ¥ homopyrimidine DNA duplex, when constituent of a DNA third strand designed to bind in the parallel binding motif. While building block 16 turned out to be incompatible with standard oligonucleotide-synthesis conditions, UV/ triplex melting experiments with third-strand 15-mers containing b-d-nucleoside 6 (from 9) showed that recognition of the four natural Watson-Crick base pairs follows the order G ¥ C % C ¥ G > A ¥ T > T ¥ A. The recognition is sequence-context sensitive, and G ¥ C or C ¥ G recognition does not involve protonated species of b-d-nucleoside 6. The data obtained fit (but do not prove) a structural model for C ¥ G recognition via one conventional and one CÀH ¥¥¥ O H-bond. The unexpected G ¥ C recognition is best explained by third-strand base intercalation. A comparison of the triplex binding properties of these new bases with those of 4deoxothymine (5-methylpyrimidine-2(1H)-one, 4 H T), previously shown to be C ¥ G selective but energetically weak, is also described.

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“…NBS 76±87 [73] N N N X HCHO, R 1 R 2 NH 60±90 [96] N N N CHO DMF, POCl 3 83 [84] N N N Br NBS 58 [75] N N N NO NaNO 2 , AcOH ± c [10] 12. This document was downloaded for personal use only.…”

Section: Synthesis By Substituent Modificationmentioning

confidence: 99%

“…[61] Scheme 26 Lithiations of Some Imidazo[1,2-a]diazines [61,84,131,133] . [75] Thus, treatment of this compound with sodium methoxide results in a mixture of two products: the tele-substituted 8-methoxy derivative 168 and the ipso (ordinarily substituted) product 5-methoxyimidazo[1,2-a]pyrazine (170). [134] Several other transformations of this type have also been reported.…”

Section: Synthesis By Substituent Modificationmentioning

confidence: 99%

Product Class 5: Azaindolizines with Two Nitrogen Atoms in the Five-Membered Ring

Neier¹,

Bellus²

2002

Category 2, Hetarenes and Related Ring Systems

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In contrast to Section 12.5.1.1.1.1, where in most cases the first reaction step is the quaternization of a pyridin-2-amine derivative followed by nucleophilic attack of the 2-amino group on an appropriate functional group to form the imidazole ring, several ring closures have been elaborated starting from substituted pyridin-2-amines. In these cases, the â-carbon atom of the carbon chain attached to the 2-amino group bears an appropriate functional group, and a nucleophilic attack of the pyridine ring nitrogen atom at this center results in formation of the imidazole ring. Such syntheses are shown in Scheme 8.

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Heterocycles. 167. Telesubstitution and other transformations of imidazo[1,2-a]- and s-triazolo[4,3-a]pyrazines

Cited by 41 publications

References 2 publications

2- and 3-substituted imidazo[1,2-a]pyrazines as inhibitors of bacterial type IV secretion

2- and 3-substituted imidazo[1,2-a]pyrazines as inhibitors of bacterial type IV secretion

Evaluation of Novel Third-Strand Bases for the Recognition of a C⋅G Base Pair in the Parallel DNA Triple-Helical Binding Motif

Product Class 5: Azaindolizines with Two Nitrogen Atoms in the Five-Membered Ring

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