Simultaneous Determination of Carbinoxamine,Pholcodine, and Ephedrine in Antitussive Preparation by High-Performance Liquid Chromatography and Thin-Layer Chromatography-Densitometry

JPC – Journal of Planar Chromatography – Modern TLC - Simple, accurate, precise, sensitive, and validated high-performance liquid chromatography (HPLC) and thin-layer chromatography...     

Remarkably Efficient and Direct Route to Quinolines and Benzoazepines from the Condensation of Benzoxazinediones with Phosphonium Carbanion Salts

Treatment of 2H‐3,1‐benzoxazine‐2,4(1H)‐dione (1a) with vinyltriphenylphosphonium bromide (2a) gives substituted benzoazepine 8a (48% yield) and indolizinone 12 (27% yield), whereas substituted quinolinone 15 and benzoazepine 8b were isolated from the reaction of N‐methylisatoic anhydride (1b) and 2a. Furthermore, a series of quinoline derivatives was synthesized from the reactions of 1a and 1b with allyl‐(2b), alkyl‐(2c), (2d), and cyanomethyl‐(3) triphenylphosphonium salts.     

An efficient synthesis of novel heterocyclic systems incorporating coumarin moiety

Polyfunctional 3-chloro-3-(4-chlorocoumarin-3-yl)prop-2-enal ( 1 ) used as a precursor for heterocyclic synthesis. Dichloro-aldehyde 1 was allowed to react with variable nucleophilic reagents, and a diversity of heterocyclic systems linked coumarin moiety at position 3 was synthesized. The reaction of compound 1 with guanidine and cyanoguanidine produced 3-(pyrimidin-4-yl)-4-chlorocoumarins 2 and 3 . Treating compound 1 with 3-amino-1,2,4-triazole and 2-aminobenzimidazole yielded triazolo[4,3-a]pyrimidine 4 and pyrimido[1,2-a]benzimidazole 5 . The treatment of compound 1 with cyanoacetamide, N-benzyl-2-cyanoacetamide, and 1H-benzimidazolylacetonitrile gave 2(1H)-pyridones 6 , 7 and pyrido[1,2-a]benzimidazole 8 . The reaction of compound 1 with 5-amino-3-methyl-1H-pyrazole and 6-aminouracil afforded pyrazolo[3,4-b]pyridine 9 and pyrido[2,3-d]pyrimidine 10 , respectively. Compound 1 reacted with ethylenediamine, o-phenylenediamine , o-aminophenol, and o-aminothiophenol leading to 5-(imidazolylmethyl)chromeno[4,3-e] [1,4]diazepine ( 12 ), 3-(benzodiazepin/benzoxazepin-2-yl)-4-chlorocoumarins 13 , 14 , and 6-(benzothiazol-2-ylmethyl)chromeno[4,3-b][1,5]benzothiazepine 16 , respectively. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data.     

Synthesis,Reactions, and Characterization of 6-Amino-4-(Benzo[b]Thiophen-2-YL)-2-Thioxo-1, 2-Dihydropyridine-3, 5-Dicarbonitrile

Abstract

Benzothiophene -2- carbaldehyde 1 reacted with 2-cyanoethanethioamide 2 in 1:2 molar ratios to give the corresponding 6-amino-4-(benzo[b]thiophen-2-yl)-2-thioxo-1, 2-dihydropyridine-3,5-dicarbonitrile 6. The synthetic potentiality of compound 6 was investigated via its reaction with active halogen-containing reagents to afford the corresponding thieno[2,3-b]pyridine derivatives 11a,b, 14, 16, and 19. Also, compound 6 reacted with hydrazine hydrate to give the pyrazolo[3,4-b]pyridine derivative 21. Compound 21 condensed with 4-(2-thienyl)benzaldehyde to afford pyrazolo[3,4-b]pyridine derivative 23. Structural elucidation of all the newly synthesized heterocyclic compounds was based on elemental analyses, IR, ¹H NMR, and mass spectra.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Thieno[2,3-b]pyridine-2-carbohydrazide in Polyheterocyclic Synthesis: The Synthesis of Pyrido[3′,2′:4,5]thieno[3,2-d]pyrimidine,Pyrido[3′,2′:4,5]thieno[3,2-d][1,2,3]triazine,and Pyrazolyl,Oxadiazolylthieno[2,3-b]pyridine Derivatives

Pyrdine-2(1H)-thione 1 reacted with ethyl chloroacetate 2 to give 2-S-ethoxy-carbonylmethylpyridine derivative 3, which could be cyclized into thieno[2,3-b]-pyridine-2-carbohydrazide derivative 5 by boiling with hydrazine hydrate. The latter compound reacted with cinnamonitrile derivatives 6a, b, triethylorthoformate, formic acid, dimethylformamide-dimethylacetal, and diethyl carbonate to give the corresponding shiff base 7a, b and pyrido[3′,2′;-4,5]thieno[3,2-d]pyrimidine derivatives 10–13 in respective manner. On the other hand, compound 5 also reacted with carbondisulphide and phenyl isothiocyanate to afford the corresponding 2-(1,3,4-oxadiazolo-2-yl)thieno[2,3-b]pyridine derivatives 18 and 22. Finally, compound 5 reacted with some β-dicarbonyl compounds, such as ethyl acetoacetate, acetylacetone and ethyl β-arylazoacetoacetate, to yield the corresponding 2-(pyrazol-1-yl-carbonyl)thieno[2,3-b]pyridine derivatives 24, 25, and 27 respectively.     

Extensions of TOPSIS for large scale multi-objective non-linear programming problems with block angular structure

This paper focuses on multi-objective large-scale non-linear programming (MOLSNLP) problems with block angular structure. We extend the technique for order preference by similarity ideal solution (TOPSIS) to solve them. Compromise (TOPSIS) control minimizes the measure of distance, provided that the closest solution should have the shortest distance from the positive ideal solution (PIS) as well as the longest distance from the negative ideal solution (NIS). As the measure of “closeness” L_P-metric is used. Thus, we reduce a q-dimensional objective space to a two-dimensional space by a first-order compromise procedure. The concept of a membership function of fuzzy set theory is used to represent the satisfaction level for both criteria. Moreover, we derive a single objective large-scale non-linear programming (LSNLP) problem using the max–min operator for the second-order compromise operation. Finally, a numerical illustrative example is given to clarify the main results developed in this paper.     

DNA Binding and Equilibrium Investigation of the Interaction of a Model Pd(II) Complex with Some Selected Biorelevant Ligands

The Pd(DAP)Cl₂ complex, where DAP is 2,6-diaminopyridine, was synthesized and characterized. The stoichiometries and stability constants of the complexes formed between various biologically relevant ligands (amino acids, amides, DNA constituents, and dicarboxylic acids) and [Pd(DAP)(H₂O)₂]²⁺ were investigated at 25 °C and at constant 0.1 mol·dm^?3 ionic strength. The concentration distribution diagrams of the various species formed were evaluated. A further investigation of the binding properties of the diaqua complex [Pd(DAP)(H₂O)₂]²⁺ with calf thymus DNA (CT-DNA) was investigated by UV–Vis spectroscopy. The intrinsic binding constants (K _b) calculated from UV–Vis absorption studies is 1.04 × 10³ mol·dm^?3. The calculated (K _b) value was found to be of lower magnitude than that of the classical intercalator EB (ethidium bromide) (K _b = 1.23 (±0.07) × 10⁵ mol·dm^?3), suggesting an electrostatic and/or groove binding mode for the interaction with CT-DNA.     

The effective potential for the PT-symmetric and non-Hermitian (−gφ 4) field theoretic model

In this paper we investigate the vacuum condensate for the PT-symmetric and non-Hermitian (− gφ ⁴) field theoretic model by using the Oscillator Representation method. The results are extended, in the quasi-particle effective theory, to include the investigation of the effective potential, perturbatively, up to g ³. Our results reproduce the previous results about the exponential vanishing of the vacuum condensate as g → 0⁺. The reality of the vacuum energy is also confirmed.