The Acylation and Alkylation of Imidazolines and Some New Types of Imidazolines<sup>1</sup>

Marxer, A.

doi:10.1021/ja01559a065

Cited by 19 publications

(8 citation statements)

References 2 publications

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“…Reductive methylation of 1 with formaldehyde was 100% N ‐selective (observed by 1H‐NMR) but not complete. Attempts to isolate pure 1‐methyl‐2‐(4‐hydroxyphenyl)‐1 H ‐imidazoline by recrystallization or column chromatography failed.…”

Section: Resultsmentioning

confidence: 99%

Reactivity of Hydroxy and Amino Derivatives of 2-Phenyl-1H-imidazoline and 2-Phenyl-1H-imidazole toward Isocyanates: Synthesis of Appropriate Carbamates and Ureas

Pařík

Jansa

Holešová

et al. 2013

J. Heterocyclic Chem.

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Reactivity of 2‐(4‐hydroxyphenyl)‐1H‐imidazoline and 2‐(4‐hydroxyphenyl)‐1H‐imidazole toward substituted phenyl isocyanates was studied. When mentioned imidazoline was treated with 2.5 equiv of substituted phenyl isocyanate, three N,O‐dicarboxamides were prepared (substituents are H, 4‐NO2, and 4‐CH3). Subsequently, N,O‐diacetylated 2‐(4‐hydroxyphenyl)‐1H‐imidazoline was prepared and selective deprotection method was developed for preparation of 1‐acetyl‐2‐(4‐hydroxyphenyl)‐1H‐imidazoline using diethylamine in acetone. Six carbamates derived from this imidazoline were then prepared using 1.1 equiv of substituted phenyl isocyanates (substituents are H, 4‐CH3, 4‐OCH3, 4‐NO2, 4‐CN, and 3‐CF3). Finally, two carbamates were prepared from 2‐(4‐hydroxyphenyl)‐1H‐imidazole (substituents are 4‐NO2 and 4‐CN). No reactivity to imidazole ring was observed in this case. Eight derivatives were subjected to antimycobacterial screening. Concurrently, reactivity of 2‐(2‐aminophenyl)‐ and 2‐(2‐hydroxyphenyl)‐1H‐imidazole toward aliphatic and aromatic isocyanates was studied. Eight ureas were prepared using equivalent mixture of 2‐(2‐aminophenyl)‐1H‐imidazole and isocyanate (Et, Pr, isoPr, terc‐Bu, Cy, Ph, 4‐CH3C6H4, 4‐CNC6H4). Similar attempts to obtain related carbamates from 2‐(2‐hydroxyphenyl)‐1H‐imidazole lead only to three substituted phenyl carbamates (substituents are 4‐CH3, 4‐NO2, and 4‐CN). In both cases, no reactivity to imidazole ring was observed again.

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Section: Resultsmentioning

confidence: 99%

Reactivity of Hydroxy and Amino Derivatives of 2-Phenyl-1H-imidazoline and 2-Phenyl-1H-imidazole toward Isocyanates: Synthesis of Appropriate Carbamates and Ureas

Pařík

Jansa

Holešová

et al. 2013

J. Heterocyclic Chem.

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“…2 In contrast to 2a, heating nitriles with N-alkylethylenediamines gave cyclization readily to N-substituted-2-imidazoline derivatives as follows from the literature. 7 Spectroscopic studies on such compounds should provide information regarding the dichotomy between these two reactions run with N-methyl-1,3-diaminopropane or N-alkylethylenediamines. One possible explanation may reside in the different stabilization of intermediates, which would enhance or prevent the above reactions.…”

Section: Synthesesmentioning

confidence: 99%

“…Only those free bases that are basic enough are assumed to exist as strong neutral-neutral hydrogen-bonded species preventing the cyclization reaction. One exception was Nalkylethylenediamines, 7 where the cyclization probably took place because intramolecular hydrogen bonding similar to 2a was absent in the intermediate secondary thioamide.…”

Section: When Do Secondary Thioamides Not Cyclize To Cyclic Amidines mentioning

confidence: 99%

“…Indeed, N- [2-(methylamino)ethyl] (1-thyminyl)acetamide (10) has spectroscopic properties similar to those of 9, hence cyclizations to afford N-substituted-2-imidazolines were successful. 7 A correlation between the reactions of secondary thioamides and their spectroscopic properties seems to exist. Only those compounds which exhibit NMR properties similar to thioamides 1a and 2a (or amides 4 and 3), respectively, are resistant to hydrolysis and cyclization reactions presented in Schemes 1 and 2.…”

Section: When Do Secondary Thioamides Not Cyclize To Cyclic Amidines mentioning

confidence: 99%

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Correlation between the reactivity and spectroscopic properties ofN‐substituted secondary thioamides. New intramolecular N···H⁺···N binding approach and proton complexes based on thioamide ligation

Spychala

2003

Magnetic Reson in Chemistry

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On the basis of a comparison of chemical shifts and wavenumbers of several secondary thioamides and amides having monocationic substituents attached to thiocarbamoyl or carbamoyl groups by a polymethylene chain, new intramolecular unconventional N· · ·H + · · ·N hydrogen bonding effects were discovered. It is argued that the CH 2 -N rotation is hindered and two + H· · ·NHCH 3 non-equivalent protons occur in a proton spectrum of hydrochloride 1a (at 10.68 and 2.77 ppm, respectively) instead of two + NH 2 CH 3 protons. Presumably, the above steric factors inhibit the acidic hydrolysis of 1a (stabilized by strong intramolecular N· · ·H + · · ·N hydrogen bonds) to an amide and prevent intramolecular cyclization of 2a (stabilized by strong intramolecular neutral-neutral N· · ·HN hydrogen bonds) to a cyclic amidine. Postulation of additional dihydrogen bond formation is helpful in understanding the spectroscopic differences of 4 and 5. The above new bonding is also compared with intramolecular N· · ·H -N + hydrogen bonds in primary amine salts 7 and 8. In contrast to 3, a cooperative hydrogen bonded system is observed in 9 and 10. The weak hydrogen bonds in 7-10 facilitate the hydrolysis and cyclization reactions of secondary thioamides. The spectroscopic data for secondary (thio)amides are especially useful for characterizing the electronic situation at the (thio)carbamoyl nitrogen atoms and they are perfectly correlated with the reactivity. Examples of chelation of protons by thioamides (11 and 12), which contain strongly electron-donating pyrimidine groups, are presented to show the contribution of dihydrogen bonding in the protonation reaction similar to 1 and 4.

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“…The bis-amide 5 was readily dehydrated by the action of phosphorus oxychloride to give the bisnitrile 3 in good yield [17]. Both the imidazoline 6a and the tetrahydropyrimidine 6b were obtained by reaction of the bis-nitrile 3 in the presence of hydrogen sulfide with the appropriate diamine [18]. In the case of the reaction of 3 with ethylenediamine a small amount of the mono-substitution product, 4-(4-cyanophenyl)-2-[4-(4,5-dihydro-1Himidazol-2-yl)phenyl]-1,3,5-tri-azine 6c was also obtained.…”

Section: Chemistrymentioning

confidence: 99%

Synthesis of dicationic diaryltriazines nucleic acid binding agents

Spychala

Wilson

et al. 1994

European Journal of Medicinal Chemistry

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- The synthesis of 2,4-bis[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]-1,3,5-triazine 6a and 2,4-bis[4-(1,4,5,6-tetrahydropyrimidin-2-yl)phenyl]-1,3,5-triazine 6b in 3 steps from either 4-bromobenzamidine or 4-(carbamoyl)benzamidine is reported. The synthesis of 4,6-bis[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]-2-dimethylamino-1,3,5-triazine 9a and 4,6-bis[4-(1,4,5,6-tetrahydropyrimidin-2-yl)phenyl]-2-dimethylamino-1,3,5-triazine 9b in 2 steps from 1,4-dicyanobenzene is also described. The compounds 6b and 9b bind strongly to DNA model sequences and inhibit topoisomerase II from 2 microbial sources. Compounds 6a and 9a bind to both DNA and RNA model sequences whereas 6b and 9b essentially do not bind to the RNA model.

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The Acylation and Alkylation of Imidazolines and Some New Types of Imidazolines¹

Cited by 19 publications

References 2 publications

Reactivity of Hydroxy and Amino Derivatives of 2-Phenyl-1H-imidazoline and 2-Phenyl-1H-imidazole toward Isocyanates: Synthesis of Appropriate Carbamates and Ureas

Reactivity of Hydroxy and Amino Derivatives of 2-Phenyl-1H-imidazoline and 2-Phenyl-1H-imidazole toward Isocyanates: Synthesis of Appropriate Carbamates and Ureas

Correlation between the reactivity and spectroscopic properties ofN‐substituted secondary thioamides. New intramolecular N···H⁺···N binding approach and proton complexes based on thioamide ligation

Synthesis of dicationic diaryltriazines nucleic acid binding agents

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The Acylation and Alkylation of Imidazolines and Some New Types of Imidazolines1

Cited by 19 publications

References 2 publications

Reactivity of Hydroxy and Amino Derivatives of 2-Phenyl-1H-imidazoline and 2-Phenyl-1H-imidazole toward Isocyanates: Synthesis of Appropriate Carbamates and Ureas

Reactivity of Hydroxy and Amino Derivatives of 2-Phenyl-1H-imidazoline and 2-Phenyl-1H-imidazole toward Isocyanates: Synthesis of Appropriate Carbamates and Ureas

Correlation between the reactivity and spectroscopic properties ofN‐substituted secondary thioamides. New intramolecular N···H+···N binding approach and proton complexes based on thioamide ligation

Synthesis of dicationic diaryltriazines nucleic acid binding agents

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Product

Resources

About

The Acylation and Alkylation of Imidazolines and Some New Types of Imidazolines¹

Correlation between the reactivity and spectroscopic properties ofN‐substituted secondary thioamides. New intramolecular N···H⁺···N binding approach and proton complexes based on thioamide ligation