Amidines. Part 24. Influences of alkyl substituents at the amidino carbon atom on the sensitivity to substitution at the imino nitrogen atom. pK a Values of N 1 N 1-dimethylamidines

Oszczapowicz, Janusz; Ciszkowski, K.

doi:10.1039/p29870000663

Cited by 24 publications

(8 citation statements)

References 3 publications

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“…We decided to reinvestigate the electrochemical behaviour of lHCl on the basis that the observed oxidation potential (+0.90 V vs. Ag/Ag+ 0.01 M) appeared too low for the oxidation of a protonated amidine. Furthermore, the oxidation of the protonated amidine cannot involve the electron pair of the imino nitrogen as suggested by Barbey and Caullet (2) since it is the most basic of the two nitrogens due to charge delocalization (stabilization) of the conjugate acid, and it is the nitrogen that is protonated (6,7). As shown below, the anodic wave at +0.90 V is due to the oxidation of the chloride anion.…”

Section: H3cmentioning

confidence: 99%

Electrochemical behavior of amidine hydrochlorides and amidines

Daoust¹,

Lessard²

1995

Can. J. Chem.

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The electrochemical behavior of N,N-dimethyl-N'-phenylformamidine hydrochloride was studied on a platinum electrode. The oxidation peak at +0.90 V vs. Ag/Ag+ 0.01 M (in CH,CN -0.1 M LiC10,) was assigned to the oxidation of the chloride anion. N,N-Dimethyl-N'-(4-chlorophenyl)formamidine and N,Ndimethyl-Nf-(2-chlorophenyl)formamidine were isolated from the preparative electrolysis of this amidine hydrochloride. The electrochemical behavior of N-phenylbenzamidine hydrochloride and N-phenylcyclohex-3-enecarboxamidine hydrochloride was also studied at platinum and at vitreous carbon. Cyclic voltammetry of a number of amidines was performed. Only N-arylbenzamidines showed a reduction peak at potentials less negative than -3.0 V vs. Ag/Ag+ 0.01 M (discharge potential of the medium at vitreous carbon). Preparative electrooxidations of all amidines studied were unsuccessful because of strong and rapid passivation of the anode.Key words: amidine, electrochemical oxidation, chloride, amidine hydrochloride.

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Section: H3cmentioning

confidence: 99%

Electrochemical behavior of amidine hydrochlorides and amidines

Daoust¹,

Lessard²

1995

Can. J. Chem.

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“…This behaviour was observed for other cyclic [5,6] and acyclic [7] amidines. In order to quantify these effects, the Hammett relationship [8] (Equation 1) was applied [9], log K a /K 0 = ρ.σ (1) rendering a slope value ρ=1.50 (r=0.9898, s=0.63).…”

Section: Introductionmentioning

confidence: 52%

1H‐4,5,6,7‐Tetrahydro‐1,3‐diazepines. part II: basicity and hydrolysis of 1, 2‐diaryl derivatives

Hedrera

Perillo

Fernández

2001

Journal of Heterocyclic Chem

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Basicity and alkaline hydrolysis of 1,2-diaryl-1H-4,5,6,7-tetrahydro-1,3-diazepines 1 are studied. Results are analyzed on the basis of Hammett and Swain-Lupton constants, finding good structure-basicity correlation when both, inductive and mesomeric effects, are considered together. Regioselectivity is observed in the alkaline hydrolysis of compounds 1, and it is analyzed in light of the stereoelectronic control theory. Results are compared with those previously obtained for five and six membered ring homologues: 1H-4,5-dihydroimidazoles and 1,4,5,6-tetrahydropyirimidines respectively.

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“…37 Other amidines were obtained according to previously described procedures: FDM, 38 ADM, 39 PrpDM, 39 iBtrDM, 39 and PivDM. 40 The purity of the amidines studied was above 95%, as judged by gas chromatography. The details of the GC analysis have been given elsewhere: FDM, 41 ADM, 41 PrpDM, 42 iBtrDM, 42 and PivDM; 42 iValDM and cHexDM were analyzed under the conditions used for the PivDM series.…”

Section: Experimental Materialsmentioning

confidence: 94%