Synthesis and characterization of captopril derivatives

To develop more potential angiotensin converting enzyme (ACE) inhibitors, a series of captopril (Cap) derivatives were synthesized, including Cap-glycine methyl ester, Cap-l-alanine methyl ester, Cap-l-aspartic acid dimethyl ester, Cap-l-lysine methyl ester, Cap-O-acylisourea, acetyl captopril, and benzoyl captopril. The resulting products were characterized by IR and UV–visible spectroscopy and MS, which showed the desired products were successfully synthesized. This could serve as a guide for rational design of highly potent ACE inhibitors.     

Synthesis and characterization of new hexahelicene derivatives

The synthesis and structural characterization of a new hexahelicene derivative 2 is reported. This compound features a new type of structure bearing a bromine atom and a methoxy group. Suitable crystals of the latter indicate that its conformation closely resembles that of the unsubstituted [6]helicene, whose idealized symmetry is C2. This 3-bromo-14-methoxyhexahelicene was subjected to lithiation/phosphinilation and yielded the new 3-methoxy-14-(diphenylphosphino)hexahelicene 3.     

Synthesis and characterization of novel spirooxazacamphorsultam derivatives

Derivatives of camphorsultam which contain novel spirooxazolidine and spirooxazine structures have been prepared in high yield and purity. Though it was expected that the ketone moiety would undergo acetal formation, the imine instead underwent reaction and was proven by X-ray crystallography and 2D NMR techniques. The initial ketone-containing derivatives were then reduced to produce exo-hydroxy analogs that have potential as a new family of chiral auxiliaries.     

Synthesis and characterization of novel derivatives of triazinone

Triazinone is a kind of heterocyclic compound with potential biological activity. The molecular design, synthesis and optimization of lead compounds are important to the development of insecticides. Six new triazinone derivatives were synthesized and characterized by IR, ¹H-NMR and MS spectra. The mechanism of synthesis of aminotriazinone was discussed. Translated from Huaxue Tongbao (Chemistry), 2006, 69(9): 674–679 (in Chinese)     

Synthesis and structure characterization of novel luteolin derivatives

A series of novel luteolin derivatives was synthesized employing the Vilsmeier-Haak-Arnold reaction from the intermediate compound 3′,4′,7-trichloro-5-hydroxyflavone, which was obtained from luteolin. These derivatives may be used to improve the pharmacological activities of luteolin.     

Synthesis and characterization of some important indazolyl derivatives

A series of some important indazolyl derivatives of pyrazoles, diazepines, thiopyrimidines, thiazines and chromones were synthesized and characterized with the help of spectral data. Some of the synthesized compounds are tested for antimicrobial and antioxidant activities.     

Synthesis and structural characterization of ferrocenyl indenyl derivatives

In this study, four ferrocenyl indenyl derivatives, C₉H₇–C≡C–Fc (1), C₉H₇–C≡C–Ph–Fc (2), C₉H₇–C≡C–Ph–C≡C–Fc (3), and C₉H₇–Ph–C≡C–Fc (4) (where C₉H₇=indenyl; Fc=C₅H₅FeC₅H₄; Ph=C₆H₅), have been synthesized by Sonogashira and Suzuki cross-coupling reactions and characterized by elemental analysis, and FT-IR, ¹H, ¹³C-NMR, and MS spectroscopic methods, respectively. The molecular structures of 1, 2, and 4 were determined by X-ray single crystal diffraction. Two molecules appeared in the crystal structure of 4, and they interact through an intermolecular hydrogen bond. The electrochemical redox potential differences in 1–4 were investigated using cyclic voltammetry and calculations.     

Synthesis and characterization of water-soluble amino fullerene derivatives

[formula: see text] A series of amino-substituted methanofullerene derivatives were prepared by mono-, tris-, and hexa-Bingel-Hirsch reactions using an N-protected malonate derivative. Upon scission of the protecting groups, the e,e,e-tris- and octahedral Th hexa-methano amino fullerenes were found to be among the most water-soluble fullerene derivatives yet prepared. 3He NMR data on corresponding adducts of 3He/C60 helped verify the assigned structures. UV spectral studies confirmed the influence of aggregation on solubility of these adducts in water.     

Synthesis and characterization of lead phthalocyanine and its derivatives

Lead (II) phthalocyanine (PbPc); lead (II) tetranitro phthalocyanine (PbTNP) and lead (II) tetraamino phthalocyanine (PbTAP) are synthesized in pure state. These complexes are characterized using elemental analysis, UV-visible, IR-spectroscopy, X-ray crystallography and thermogravimetry. Kinetic and thermodynamic parameters associated with the thermal decomposition were calculated using thermogravimetric data. Electrical conductivity studies are done for all the three complexes using two-probe technique in the temperature range from 30 to 200 °C. The electrical conductivity observed at 30 °C are in the order PbTAP > PbTNP > PbPc. The relevant electrical conductivity data observed are reported.     

Synthesis and characterization of novel dipyridylbenzothiadiazole and bisbenzothiadiazole derivatives

Novel dipyridyl compounds containing a mono- and bisbenzothiadiazole unit were synthesized using the Stille coupling reaction. Their pyridinium salts, viologen analogues, were also prepared by the N-alkylation. The X-ray crystallographic analysis of the compounds containing a benzothiadiazole ring revealed nonplanar molecular structures and unique crystal structures depending on the nitrogen positions. The dipyridyl compounds are efficient fluorophores with high electron affinity. The derivative afforded complexes with chloranilic acid and cyanuric acid composed of hydrogen bonding networks. The methyl viologen analogues showed two-stage one-electron reduction waves.     

Synthesis and characterization of photolabile o-nitrobenzyl derivatives of urea

We present here the synthesis and characterization of four photolabile derivatives of urea in which alpha-substituted 2-nitrobenzyl groups are covalently attached to the urea nitrogen. These derivatives photolyze readily in aqueous solution to release free urea. The alpha-substituents of the 2-nitrobenzyl group strongly influence the rate of the photolysis reaction measured with transient absorption spectroscopy. Rates of photolysis at pH 7.5 and room temperature (approximately 22 degrees C) for N-(2-nitrobenzyl)urea, N-(alpha-methyl-2-nitrobenzyl)urea, N-(alpha-carboxymethyl-2-nitrobenzyl)urea, and N-(alpha-carboxy-2-nitrobenzyl)urea are, respectively, 1.7 x 10(4), 8.5 x 10(4), 4.0 x 10(4), and 1.1 x 10(5) s(-)(1). The quantum yields determined by measurement of free urea following irradiation by a single laser pulse at 308 nm were 0.81 for N-(2-nitrobenzyl)urea, 0.64 for N-(alpha-methyl-2-nitrobenzyl)urea, and 0.56 for N-(alpha-carboxy-2-nitrobenzyl)urea. The caged N-(alpha-carboxy-2-nitrobenzyl)urea is not a substrate of the enzyme urease, while the photolytically released urea is. Also, neither this caged urea nor its photolytic side products inhibit hydrolysis of free urea by urease. Thus, the alpha-carboxy-2-nitrobenzyl derivative of urea is suitable for mechanistic investigations of the enzyme urease.     

Synthesis and characterization of copolymers of β-cyclodextrin derivatives

Cyclodextrins (CDs) are cyclic oligosaccharides made up of d-glucose units connected by 1,4-glucosidic linkages. β-CD is a cyclical starch derivative containing seven glucopyranose units. β-CD derivatives have characteristic property of larger surface area, robust mechanical strength, high surface to volume ratio, electrical and optical properties for analyte determination, good dispersion, easy removal of the template, surface modification, functionalization and handling capacity. In this work, an attempt is made to prepare succinyl-β-CD-acrylamide (S-β-CD-AA) copolymer and β-CD-malic anhydride (β-CD-MAH) copolymer. For the synthesis of S-β-CD-AA, S-β-CD derivative is prepared and further, acrylamide (AA) along with cross-linker undergoes free radical copolymerization for the formation of gel like product. The degree of succinylation (DS) of β-CD derivative is estimated. S-β-CD-AA copolymer showed potential swelling, and deswelling characteristic. Another copolymer is prepared from β-CD malic anhydride derivative. Further, the derivative is treated with cellulose and ethylene diamine tetra acetate (EDTA) to form β-CD-MAH copolymer. The two derivatives are characterized by several techniques. Thermal stability of these copolymers is estimated with the help of thermogravimetric analysis. The basic characterization of the presence of functional groups is done using UV–visible spectroscopy, and infrared spectroscopy. The elemental analysis helped to estimate C, H, N, S in the synthesized compounds. The surface morphology characterization is done with the help of scanning electron microscopy. X-ray diffraction analysis helped in determination of crystal structure of β-CD-MAH. β-CD derivatives prepared may be potential candidate to prepare inclusion complex, in drug delivery, drug loading and several similar applications.     

Synthesis and characterization of solvated trifluoroacetate alkaline earth derivatives

The synthesis and characterization of the trifluoroacetic acid (H-TFA) derivatives of a series of alkaline earth congeners was undertaken through the dissolution of the alkaline earth (A^E) metal in H-TFA. After drying, the resulting reaction powders were independently crystallized from Lewis basic solvents [pyridine (py) or tetrahydrofuran (THF)] as diverse A^E-TFA derivatives. For the smallest cation, an octahedrally bound monomer Mg(TFA)₂(py)₄ (1) was isolated, wherein the TFA ligands were all terminally (TFA) bound. The remaining compounds were found to adopt polymeric structures with: only bridging (μ-TFA) ligands for {[Ca₂(μ-TFA)₃(THF)₄](μ-TFA)}_n (2); a mixture of μ-TFA and chelating bridging (μ_c-TFA) ligands in {[(μ-TFA)₂Sr(μ_c-TFA)][H-py]py}_n (3); and only μ_c-TFA ligands for {[Ba(μ_c-TFA)₂(μ_c-TFA)(py)][H-py]}_n (4) structure. The later two structures were solved with a pyridinium salt located in the lattice. The trend observed for the TFA ligand was that as the cation increases in size, the ligands transform from bridging to chelating bridging due to the increased coordination sphere of the metals. Elemental analyses, solid-state, and solution multinuclear NMR, and FTIR data confirm the bulk powders were consistent with the X-ray structures.     

Synthesis and structural characterization of novel tetranuclear organotitanoxane derivatives

Synthesis of the novel titanoxane compounds, [(TiCl)(TiOH){(Ti)[μ-(η(5)-C(5)Me(4)SiMe(2)O-κO)](2)(μ-O)}(2)(μ-O)] (4) and [{Ti[μ-(η(5)-C(5)Me(4)SiMe(2)O-κO)](μ-O)}(4)] (5) by controlled reaction of the dinuclear titanium oxo complex [{Ti{μ-(η(5)-C(5)Me(4)SiMe(2)O-κO)}Cl](2)(μ-O)] (1) with 2 equiv of LiOH is reported. Complex 4 is innovative and remarkable. It is one of the rare known examples of tetranuclear stable terminal hydroxo titanium complexes, with an open-chained structure, which coincides with the transient metal monohydroxo proposed in the stepwise pathway employed to justify the formation of the hexanuclear complex [{Ti[μ-(η(5)-C(5)Me(4)SiMe(2)O-κO)](μ-O)}(6)] (3) from 1. (1)H DOSY experiments were used to characterize complex 4. In addition, the structures of compound 5 and of precursor 1 were determined by single-crystal X-ray diffraction studies.     

Synthesis and characterization of polymers from itaconic acid derivatives

Some itaconic acid derivatives were prepared and polymerized, in which itaconic acid (IA), β-monoalkyl itaconates (mRI), dialkyl itaconates (DRI), N-substituted itaconamates (IAE), itaconamides (IAm), itaconic anhydride (IAn), N-alkylitaconimides (RII), and N-(alkyl-substituted phenyl)itaconimides (RPhII) are included. The polymerization reactivity was examined, and discussed in relation to the structure of the monomers. The structure and some properties of the resulting polymers were investigated. Some citraconic acid (CA) and mesaconic acid (MA) derivatives were also polymerized, and their reactivities were compared with the corresponding IA derivatives.     

3,5-二甲氧基苯乙烯环酮类化合物的合成及表征

研发环氧合酶(COSX)/5-脂氧酶(5-LOX)双重抑制剂是降低非甾体抗炎药胃肠道(GI)副作用的有效途径之一[1]。大多数二叔丁基苯酚类化合物具有较强的COX/5-LOX双重抑制作用,例如达布飞龙甲磺酸盐(darbufelone mesilate)用于治疗类风湿性关节炎和骨关节炎,GI不良反应小且长效,目前处     

Synthesis and characterization of poly(vinylcyclohexane) derivatives

Six nearly monodisperse substituted poly(styrene) homopolymers, poly(styrene) (PS), poly(2-methylstyrene) (P2MS), poly(3-methylstyrene) (P3MS), poly(4-methylstyrene) (P4MS), poly(tertiary-butylstyrene) (PtBS), and poly(α-methylstyrene) (FαMS) were anionically polymerized and subsequently saturated using heterogeneous hydrogenation techniques to poly(vinylcyclohexane) (PVCH), poly(2-methylvinylcyclohexane) (P2MVCH), poly(3-methylvinylcyclohexane) (P3MVCH), poly(4-methylvinylcyclohexane) (P4MVCH), and poly(tertiary-butylvinylcyclohexane) (PtBVCH), respectively. In each case, except PαMS, the materials were saturated to > 99% conversion with no chain degradation. PS hydrogenations required the addition of small amounts of tetrahydrofuran to the reaction solvent cyclohexane to enhance miscibility and eliminate large-scale chain degradation. Density gradient and differential scanning calorimetry (DSC) measurements were used to characterize the density and glass transition temperature, T_g, of the unsaturated and saturated polymers. Saturation reduces the density by 3% to 11% and changes T_g substantially. The greatest variation in T_g is obtained with the 3-methyl substituted species where a 63°C increase is observed, while the highest measured T_g is 186°C for P2MVCH. Small-angle neutron scattering (SANS) experiments on binary mixtures of hydrogenous and deuterium labeled PVCH derivatives provided a determination of bulk chain statistics. The statistical segment length is relatively insensitive to vinylcyclohexane ring substitution, except with P3MVCH where a 20% greater value is obtained. ©1995 John Wiley & Sons, Inc.