The synthesis and spectral characterization of novel nitrodiene compounds from thiols

Novel S-, S,S- and S,O-substituted nitrodiene compounds were synthesized from the reactions of 2-nitro-pentachloro-1,3-butadiene (1) and various thiols in different solvent media. The N,S-substituted nitrodienes also were achieved by the reactions of S-substituted nitrodienes with using morpholine, piperidine and piperazine derivatives. All of the new compounds were characterized by elemental analysis, UV-VIS, FT-IR, ¹H-NMR, NMR and mass spectroscopy.     

Asymmetric Synthesis of （R）- and （S）-Moprolol

A simple and effective procedure for the enantioselective synthesis of （R）- and （S）-moprolol was described. The key step was the asymmetric synthesis of enantiopure （R）- and （S）-guaifenesin, which were synthesized from enantioenriched （R）-3-chloro-l,2-propanediol and （S）-epichlorohydrin via kinetics of hydrolysis resolution of racemic epichlorohydrin by chiral Salen-Co^Ⅲ complex. The e.e. values of both the optical compounds were above 98%, and the chemical structures of the target compounds were confirmed by ^1H NMR, ^13C NMR, IR, and MS.     

Stereochemical effect on biological activities of new series of piperidin-4-one derivatives

New series of (2S,3R,4S,6R)-3-methyl-4-alkyl-2,6-diarylpiperidin-4-ol were synthesised by the reduction of cis-3-alkyl-2,6-diarylpiperidin-4-one using Grignard reagent. The structural assignments and conformational studies of the synthesised compounds were established based on the IR, ¹H NMR, ¹³C NMR, NOESY and mass spectral studies. Their stereochemical effect on antibacterial, antifungal and anthelmintic activities was studied.     

Two new ceramides from <Emphasis Type="Italic">Zephyranthes candida</Emphasis>

Two new ceramides were isolated from the bulbs of Zephyranthes candida. Their structures were established as (2S,3S,4R,13E)-1,3,4-trihydroxy-2-[(2′R)-2′-hydroxytetracosanoylamino]-13-octadecene, named zephyranamide A (1) and (2S,3S,4R)-1,3,4-trihydroxy-2-octacosanoylaminohexadecene, named zephyranamide B (2). The structures of the new compounds were elucidated by spectral techniques including ¹H NMR, ¹³C NMR, as well as HSQC, HMBC, DEPT, and COSY.     

Synthesis and Characterization of Nitrogen and Sulfur Containing 1,4-Naphthoquinones

Abstract

New N,S-disubstituted naphthoquinones were synthesized by reactions of S- and N-nucleophiles with 2,3-dichloro-1,4-naphthoquinone. 2-(Hexadecylthio)-3-(phenylamino)-naphthalene-1,4-dione 5a was synthesized by reaction of 2-chloro-3-(phenylamino)-naphthalene-1,4-dione 3a with hexadecanethiol 4a. The structures of the new synthesized naphthoquinone derivatives were determined by micro analyses and spectroscopic methods (FT-IR, ¹H NMR, ¹³C NMR, MS, and UV/Vis.). Photo- and electrochemical properties of selected compounds were investigated by using fluorescence spectroscopy and the cyclovoltammetry method.     

Effect of the variation of swallow-tailed groups on the mesomorphic and electro-optical properties of chiral compounds derived from (S)-2-(6-hydroxy-2-naphthyl)propionic acid

Three homologous series of chiral swallow-tailed compounds, alkyl (S)-2-{6-[4-(4′-alkoxyphenyl)benzoyloxy]-2-naphthyl}propionates, (S)HNP(p,n,q) derived from (S)-2-(6-hydroxy-2-naphthyl)propionic acid in conjugation with a variety of swallow-tailed groups, attached to the external side of the chiral centre, have been synthesized and their mesomorphic and electro-optical properties studied. Both (S)HNP(p,1,2) and (S)HNP(p,1,3) exhibited an enantiotropic antiferroelectric SmC*_A phase. This implys that the swallow-tailed groups in the molecules favour zigzag pairing of the molecules in the smectic phase. The maximum P _S values of compounds (S)HNP(p,1,2) in the antiferroelectric phase were measured in the range 21–30 nC cm^-2; those of compounds (S)HNP(p,1,3) were in the range 15–23 nC cm^-2, indicating that these chiral compounds possess low polarity. The electro-optical response of the compounds in the antiferroelectric SmC*_A phase displayed thresholdless V-shaped switching.     

RMN du 13C de Composés Méthylés Soufrés

A ¹³C NMR study of a series of methyl sulphur compounds is described. The results are discussed in terms of the deshielding effects on the methyl carbon exerted by –SH, –SMe, –SSMe, –SSEt, –SSMe, –SC(O)Me, –SC(S)Me, –SC(S)SMe. The ¹³C NMR chemical shifts of a series of S-methyl thioesters and dithioesters are compared with corresponding esters and connected with chemical properties.     

Determination of the absolute stereochemistry and the activation barriers of thermally interconvertible heterocyclic compounds bearing a naphthyl substituent

The enantiotopic methyl signals of the compounds studied were resolved in the presence of the optically active chiral auxiliary (S)-(+)-2,2,2-trifluoroanthryl ethanol, [(S)-TFAE] via complex formation between (S)-TFAE and the respective compounds. Two different solvation models were proposed for both M and P conformations leading to the assignments of the ¹H NMR signals and thus absolute conformations. The solvation models proposed also explained the strong temperature dependence of the ¹H NMR signals upon cooling. The activation barriers for interconversion between the enantiomers of the compounds studied have been determined by either temperature dependent NMR or enantioresolution on a chiral sorbent via HPLC.     

Synthesis and investigation of cytotoxicity of new N- and S,S-substituted-1,4-naphthoquinone (1,4-NQ) derivatives on selected cancer lines

1,4-Naphthoquinones (1,4-NQ) have been reported to possess a variety of pharma-cological properties including antibacterial, antifungal, antiviral, anti-inflammatory, anti-artherosclerotic, and anticancer effects. In this study, new N- and S,S-substituted-1,4-NQ derivatives were synthesized in excellent yields and were completely characterized by spectroscopic analysis IR, NMR (¹H and ¹³C), MS and microanalysis. The cytotoxic activities of 1,4-NQ derivatives were examined against to A-549, DU145, HCT-116 and MDA-MB-231 cancer cells. Among these compounds, 2-[4-(2-furoyl)piperazine-1-yl]-3-chloro-1,4-NQ 5 and 2,3-bis(cyclobuthylsulfanyl)-1,4-NQ 17 were identified as the most potent anticancer agents with cytotoxic activity against three cell lines (breast (MDA-MB-231), prostate (DU145), colorectal (HCT-116).     

Dibromido[(S,S)-ethylenediamine-N,N′-di-2-(3-cyclohexyl)propanoato]platinum(IV): synthesis,characterization, and DFT calculations

Bromido complex of platinum(IV) with (S,S)-ethylenediamine-N,N′-di-2-(3-cyclohexyl)propanoic acid was synthesized. The reaction was performed in water solution in the presence of lithium hydroxide. In this reaction system, (S,S)-ethylenediamine-N,N′-di-2-(3-cyclohexyl)propanoic acid exists as the dicarboxylato anion and coordinates as a tetradentate ONNO ligand. The complex was characterized by ¹H and ¹³C NMR, IR and UV-Vis spectroscopy. The sym-cis configuration has been elucidated using DFT calculations.     

A Mild and Highly Efficient Synthesis of Chiral N‐Dichloroacetyl‐4‐ethyl‐1,3‐oxazolidines

Chiral 2‐amino‐butanols ( 4 and 5 ) were obtained via the isolation of diastereomeric salt. Then, chiral compounds ( 6 – 9) were synthesized by a sequential procedure involving condensation of chiral 2‐amino‐butanol with ketone and dichloroacetyl chloride. All the compounds were characterized by IR, ¹H NMR, ¹³C NMR, and element analysis. The absolute configurations of ( S )‐ 8 was determined by X‐ray crystallography.     

A new benzofuran from Artemisia halodendron Turcz. ex Bess.

A new benzofuran, methyl (2S,2″S,3′E)-[2-(1″-acetoxypropan-2-yl)-2,3-dihydrobenzofuran-5-yl]acrylate (1), and 13 known compounds (2–14) were isolated from an ethanol extract of Artemisia halodendron Turcz. ex Bess. The chemical structures of these compounds were determined by 1D and 2D NMR (¹H-¹H COSY, HMBC, HMQC and NOESY) and HR-ESI-MS spectra, and results were compared with data from the literature. The effects of compounds 1–14 were measured on NF-κB activation, with compounds 2 and 3 exhibiting inhibitory activities against TNF-α-induced NF-κB reporter gene expression in HeLa cells from 10 to 100 μM.     

New Antifungal `Quinone Methide' Diterpenes from Bobgunnia madagascariensis and Study of Their Interconversion by LC/NMR

Two new `quinone methide' diterpenes with a cassane skeleton were isolated from the root bark of Bobgunnia madagascariensis (Desv. ) J. H. Kirkbr. & Wiersema (Leguminosae). The two compounds occurred as a diastereoisomer mixture 1 / 2 . Their structure was established as (4R,6aS,10aS)‐ and (4S,6aS,10aS)‐ 1,4,6a,7,8,9,10,10a‐octahydro‐4,11‐dihydroxy‐7,7,10a‐trimethyl‐2H‐phenanthro[1,2‐c]pyran‐6,12‐dione by spectroscopic methods and by comparison with the data obtained for another `quinone methide' diterpene isolated previously from the same plant and identified by single‐crystal X‐ray analysis. ¹H‐ and ¹³C‐NMR signals were assigned by extensive in‐mixture 2D correlation experiments, and ¹H‐NMR spectra of the separated diastereoisomers 1 and 2 were recorded by on‐flow LC/NMR. The interconversion of 1 and 2 was followed by repeated stop‐flow LC/NMR experiments over a two‐hour period. Compounds 1 and 2 showed moderate antifungal properties towards human pathogenic fungi, in particular the yeast Candida albicans.     

Synthesis and Antifungal Activity of Novel Chiral α-Aminophosphonates Containing Fluorine Moiety

Chiral α-aminophosphonates were synthesized using （R） or （S）-1-phenylethylamine in the presence of BF3·Et2O under microwave irradiation in moderate to good yields. The new compounds were identified by ^1H NMR, ^19F NMR, IR and elemental analysis. Their antifungal activities were evaluated and some compounds were found to exhibit excellent antifungal activities. To the best of our knowledge, this is the first report on antifungal activity of chiral α-aminophosphonates containing fluorine moiety.     

A Simple,Convenient, and Efficient Synthetic Route for The Preparation of (Z)‐3,5‐Dichloro‐N‐(3‐(4‐substitutedphenyl)‐4‐phenylthiazole‐2(3H)‐ylide)benzamide Heterocyclic Compounds from Aroyl Thiourea Derivatives via S‐cyclization Mechanism

A series of variously substituted 1,3‐thiazole heterocyclic compounds ( 3a – 3d ) were prepared by base‐catalyzed S‐cyclization of corresponding 2,4‐dichloro‐N‐{[(4‐substitutedphenyl)amino]carbonothioyl}benzamide ( 2a – 2d ) with acetophenone in the presence of bromine. The structure of all compounds was established by IR, ¹H‐NMR, ¹³C‐NMR, elemental analysis, and X‐ray crystallographic analysis.     

Another two novel ceramides from <Emphasis Type="Italic">Zephyranthes candida</Emphasis>

From the the bulbs of Zephyranthes candida (Amaryllidaceae), another two novel ceramides have been isolated and identified. The structures of the two novel compounds were established as (2S,3S,4R,21E,2′R)2-[N-(2′-hydroxynonadecanoyl)-N-(1′′,2′′-dihydroxyethyl)amino]-21-hexacosene-1,3,4-triol, named zephyranamide C (1), and 1,3,4,5,6-pentahydroxy-2-(2′-hydroxyhexacosanoyl-amino)-18-(E)-tetracosene, named zephyranamide D (2). Their structures and stereochemistries were elucidated by spectral techniques including ¹H NMR, ¹³C NMR, as well as HSQC, HMBC, DEPT, and COSY.     

Triphenylphosphine-Catalyzed Stereoselective Synthesis of Alkyl 3-(2-Naphthylsulfanyl)-2-propenoate from Alkyl Acetylenecarboxylates and 2-Naphthalenethiol

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and alkyl acetylenecarboxylates by 2-naphthalenethiol, leads to vinyltriphenylphosphonium salts, which undergo an addition–elimination reaction to produce the corresponding S-vinyl thioethers. The NMR spectra indicated that the compounds contained two stereoisomers for each S-vinyl thioether; their ratio was determined on the basis of ¹ H NMR spectra. The reaction is fairly stereoselective.     

Synthesis,characterization, CT-DNA binding and docking studies of novel selenated ligands and their palladium complexes

A novel selenated Schiff base (S) -L ¹ H has been synthesized from (2S)-1-(benzylselanyl)-3-phenylpropan-2-amine which upon reduction formed a reduced Schiff base (S) -L ² H . Palladium (II) complexes (S) -1 and (S) -2 of ligands (S) -L ¹ H and (S) -L ² H respectively were successfully synthesized. The structures of all four compounds were thoroughly identified by analytical and various spectroscopic techniques. The absolute molecular structures of the above two complexes were further confirmed by single crystal X-ray diffraction. Both (S) -L ¹ H and (S) -L ² H coordinated as monobasic ((S) -L ^1–2 ), chelating, tridentate (Se,N,O⁻) ligands resulting in the complexes of composition (S) - [PdCl( L ^1/2 )] [(S) -1/2 ]. In the crystals of complexes (S) -1 and (S) -2 , there were moderate to strong Se⋯O, CH⋯Cl and CH⋯O types of intermolecular secondary interactions. CT-DNA binding activity of these selenium-containing ligands and their palladium complexes bearing a Pd–Se bond have been evaluated for the first time by performing electronic absorption titration and fluorescence emission quenching using CT-DNA-EB and viscometric experiments. These ligands and complexes exhibited remarkable DNA binding activity as shown by their intrinsic DNA binding constants (K_b) and Stern–Volmer constants (K_sv) in the ranges 5.2–9.9 × 10⁴ and 3.6–4.7 × 10⁴, respectively. The viscosity of CT-DNA decreases with increasing concentration of these compounds. The results of the DNA-binding studies revealed that all of the compounds interact with DNA at a minor groove which was further confirmed by molecular docking studies.     

Enantioselective fluorescent sensors for amino acid derivatives based on BINOL bearing benzoyl unit

The derivatives of BINOL, (S)-1 and (R)-1, and their analogues have been prepared and the structures of these compounds have been characterized by IR, MS, ¹H, and ¹³C NMR spectroscopy and elemental analysis. The enantioselective recognition of these receptors has been studied by fluorescence titration and ¹H NMR spectroscopy. The receptors exhibited different chiral recognition abilities toward some enantiomers of chiral materials and formed 1:1 complexes between host and guest. Receptor (S)-1 or (R)-1 exhibits excellent enantioselective fluorescent recognition abilities toward amino acid derivatives.     

Synthesis,Spectroscopic, and Antimicrobial Activity Studies of Novel 10-Substituted Camptothecin Phosphorothioate Analogs

Abstract

A series of title compounds 2 and 3 were efficiently synthesized via the condensation of 10–hydroxycamptothecin with various symmetric (O,O′-monoaryl)-thiophosphoryl chlorides and asymmetric (O-ethyl-O′-aryl)-thiophosphoryl chlorides in sodium hydroxide powder and acetonitrile system. The structures of title compounds 2 and 3 were confirmed by elemental analysis, IR, ¹H NMR, ¹³C NMR, ³¹P[¹H] NMR,and mass spectral data. These symmetric [(O,O′-monoaryl)-thiophosphoryl)]-(20S)-camptothecin (2a–f) and asymmetric [(O-ethyl-O′-aryl)-thiophosphoryl)]-(20S)-camptothecin (3a–f) compounds were also tested for their in vitro antimicrobial activities against some bacterial strains, namely, S. aureus, B. Simplex, E. acetylicum, E. coli, P. aeruginosa, S. flexenari, S. aureus, S. typhi, and some fungal strains Aspergillus niger, Aspergillus flavus (molds), S. cerevisiae, C. albicans, T. longifucus, A. flavus, M. canis, F. solani, and C. glaberata (yeasts).

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