13563-04-7

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The series of derivatives of substituted N-pyridinylsalicylamides were synthesized. The compounds were evaluated for in vitro antimycobacterial activity against Mycobacterium avium and two strains of Mycobacterium kansasii. In the quantitative structure activity relationships analysis (QSAR), the Free-Wilson and Hansch approaches were used but the analysis was not significant. (The standard deviations of regression coefficients were greater than the values of the coefficients). The molecules were separated the heterocyclic and salicyl moiety in the molecules, and the study of influences of substituents on salicyl moiety was used, as well. 5-Chloro-pyridin-2-yl, and the substitution of the salicyl moiety by chlorine in position 4 or 5 had the strongest influence on the increase in antimycobacterial activity.

A sensitive spectrofluorimetric determination of zinc (II) with N-(2'- pyridyl)-2-hydroxybenzamide (NPHB) in Brij-35 micellar medium is described. The calibration graph is linear over the range 8-200 ng/ml with a regression coefficient of 0.9997. Relative standard deviation was calculated at 0.050 and 0.150 μg/ml and found to be 2.8% and 2.1% respectively. The method is relatively free from interference and has been satisfactorily applied for the determination of zinc (II) in the samples of milk and pharmaceutical formulations.

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The nucleophilic second-order rate constants for the reactions of ionized phenyl salicylate (PS-) with primary and secondary amines have revealed Broensted plots of slopes βnuc1 = 0.52+/-0.06 and βnuc2 = 0.27+/-0.05, respectively.The suggested stepwise reaction mechanism involves the intramolecular proton transfer from cationic nitrogen to the anionic phenolic oxygen to form the monoanionic tetrahedral addition intermediate as the rate-determining step.The low value of βnuc2 is attributed to the extensive of proton transfer in the late transition state while the large value of βnuc1 is ascribed to the proton transfer in the early transition state of the rate-determining step.However, these low and high values of βnuc2 and βnuc1, respectively, are also compatible with the occurence of respective early and late transition states in the rate-determining step involving concerted intramolecular general base-catalysed nucleophilic attack at the carbonyl carbon of PS-.Significantly large positive deviations from Broensted plots have been observed for the reactivities of α-nucleophiles toward PS-.Monoprotonated ethane-1,2-diamine is ca. 20-fold more reactive than would be expected from its basicity, and this is attributed to the occurence of the intramolecular general acid catalysis.The reactions of PS- with hydroxylamine and N-methylhydroxylamine involve ca. >/=70 percent aminolysis and -.

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A new synthetic method for primary 2-aminopyridine derivatives is described.Treatment of the imidoyl chlorides of 1,3-benzoxazines (1a-i) with pyridine N-oxides resulted in the introduction of an oxazine moiety into the α-position of the pyridine ring through rearrangement of the initially formed reaction adduct.Acid hydrolysis of the rearrangement products afforded 2-aminopyridine derivatives in excellent yields.When methoxypyridine N-oxides were used, products of a different type (10 and 14) were obtained.