Justierbare Elektrophilie durch kooperative Wasserstoffbrücken

Bauer, Mirko; Spange, Stefan

doi:10.1002/ange.201103585

Cited by 1 publication

(3 citation statements)

References 29 publications

(9 reference statements)

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“…2,6‐Diaminopyridine derivatives as 2,6‐diacetamidopyridine (DACP) are often used as supramolecular complexation agents for BA because of the hydrogen bonding sequence (DAD), which is complementary to that of the keto form (ADA) of 4 b . As described above, this complexation should not influence the keto–enol tautomerism of 4 b .…”

Section: Resultsmentioning

confidence: 99%

“…Those compounds 4 are accessible by nucleophilic aromatic substitution of 2,4‐dinitrofluoro‐benzene with barbituric acid salts . The mono N‐ alkyl substituted BA 4 b is beneficial to obtain a better solubility in nonpolar solvents . Additionally, the n ‐butyl group barricades one hydrogen‐bonding sequence of the BA, thus solely a 1:1‐complex formation can take place ,…”

Section: Introductionmentioning

confidence: 99%

“…According to our previous studies,, the nucleobase derivatives 1‐ n ‐butylthymine (BuTy), 9‐ethyladenine (EtAd), 1‐ n ‐butylcytosine (BuCy), and 9‐ethylguanine (EtGu), and 2,6‐diacetamidopyridine (DACP) were used as receptors (Scheme ) to study the base pairing effect.…”

Section: Introductionmentioning

confidence: 99%

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Interactions of Enolizable Barbiturate Dyes

Schade

Schreiter

Rüffer

et al. 2016

Chemistry A European J

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The specific barbituric acid dyes 1-n-butyl-5-(2,4-dinitro-phenyl) barbituric acid and 1-n-butyl-5-{4-[(1,3-dioxo-1H-inden-(3 H)-ylidene)methyl]phenyl}barbituric acid were used to study complex formation with nucleobase derivatives and related model compounds. The enol form of both compounds shows a strong bathochromic shift of the UV/Vis absorption band compared to the rarely coloured keto form. The keto-enol equilibria of the five studied dyes are strongly dependent on the properties of the environment as shown by solvatochromic studies in ionic liquids and a set of organic solvents. Enol form development of the barbituric acid dyes is also associated with alteration of the hydrogen bonding pattern from the ADA to the DDA type (A=hydrogen bond acceptor site, D=donor site). Receptor-induced altering of ADA towards DDA hydrogen bonding patterns of the chromophores are utilised to study supramolecular complex formation. As complementary receptors 9-ethyladenine, 1-n-butylcytosine, 1-n-butylthymine, 9-ethylguanidine and 2,6-diacetamidopiridine were used. The UV/Vis spectroscopic response of acid-base reaction compared to supramolecular complex formation is evaluated by (1)H NMR titration experiments and X-ray crystal structure analyses. An increased acidity of the barbituric acid derivative promotes genuine salt formation. In contrast, supramolecular complex formation is preferred for the weaker acidic barbituric acid.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%