3,5—二羟基甲苯比色法测定棉纤维表面糖的方法研究

本文研究了在非离子表面活性剂存在下,糖在强酸介质中转化成糠醛类衍生物同3.5-二羟基甲苯发生显色反应的条件。在硫酸介质中,糠醛与3,5-二羟基甲苯形成化合物的最大吸收波长为λ_(max)=425nm,线性范围0.04～0.20mg/ml,用于测定棉纤维表面的糖,方法的相对标准偏差为1.3％,回收率92％～105％。     

Common Pharmacophore Model and 3D-QSAR Analysis of Two Different Tyrphostin Families

Iteceptortyrosinekinases(RTKs)havebeenknowntoplayacrucialroleinthecellularsigllultrallsdLlctionpathways.The[IERZproto-oncogenecodesforakindofRTKwhichbashonlologytotheepidermalgrowthfactor(EGF)receptor(HERI).Anlpliticationoftileill-RZgenehasbeenfoundinabout30%ofprimarybreast.ovary,andgastriccarcinolllas=.Survivalratesandtumoraggressivenesscanbedirectl}'correlatedtothelevelof11ERZexpression.Intillsregard,regulatingthecelluarsignaltransductionvininhibitionofHERZhasbeenconsideredapromis…     

Application of Et3NHCl-AlCl3 Ionic Liquid as an Initiator in Cationic Copolymerization of 1, 3-Pentadiene with Styrene

Room temperature ionic liquids (RTILs) as advanced, technological solvents can be designed to fit a particular application. They used as green “media and/or catalysts” for chemical synthesis have been extensively reviewed recently. RTILs1 not only show …     

Formal asymmetric synthesis of (+)-tofacitinib

Tofacitinib is an efficient and selective Janus kinase 3 (JAK3) inhibitor, and is used as an immunosuppressant drug for the treatment of rheumatoid arthritis and transplant patients. Herein we report a concise formal asymmetric synthesis of tofacitinib from homochiral 1,3-dioxolanone 10b, which was elaborated through a highly stereoselective Michael addition followed by solvent-free removal of the chiral auxiliary and ring cyclization to furnish chiral imide 8. The preparation of tofacitinib’s precursor 16 could be obtained after reduction of 8 followed by sequential oxidation, reductive amination and S_NAr reactions.     

3-氧杂-8-氮杂双环[3.2.1]辛烷盐酸盐的合成

以己二酸为初始原料,依次经酰氯化,溴代,苄胺环合,水解,还原,脱水环合,氢解脱苄和成盐等8步反应,合成了3-氧杂-8-氮杂双环[3.2.1]辛烷盐酸盐,总收率23%,纯度100%,其结构经1H NMR确证。     

Synthesis of Substituted 3H-Indole-modified b-Cyclodextrin

The hydrophobic cavities of cyclodextrins and the inclusion with various organic molecules in the aqueous solution make them useful in chemical and biological activities1, one of which is the modified cyclodextrins acting as indicators of molecular recognition. Cyclodextrins, which are spectroscopically inert, can be converted into spectroscopically active compounds by modifing one or two of the hydroxy groups with appropriate chromophores, and used as molecular sensor due to the capability of…     

Synthesis, Reactions, and Pharmacological Screening of Heterocyclic Derivatives Using Nicotinic Acid as a Natural Synthon

Summary. A series of substituted pyridine derivatives were prepared from 3-acetylpyridine, which was prepared from the corresponding nicotinic acid as a natural starting material. Reaction of 3-acetylpyridine with indole-3-carboxaldehyde afforded the corresponding 3-β-(3-indolyl)acryloylpyridine, which was reacted with hydroxylamine hydrochloride in pyridine or acetic acid in the presence of sodium acetate to afford 3-β-(3-indolyl)acryloylpyridine oxime and oxazole derivatives. The oxime was treated with ethyl isothiocyanate or toluene-3,5-diisocyanate in refluxing dioxane to give the corresponding ethyl thiosemicarbazide and 3,5-bissemicarbazide derivative. 3-β-(3-Indolyl)acryloylpyridine was condensed with malononitrile in refluxing ethanol in the presence of piperidine as a catalyst to give cyanoaminopyrane, while it was condensed with ethyl cyanoacetate or malononitrile in the presence of ammonium acetate to yield cyanopyridone and cyanoaminopyridine derivatives. Cyclization of acryloylpyridine with o-phenylenediamine in refluxing butanol led to the formation of the corresponding benzodiazipine via the intermediate A. Finally, cycloaddition reaction of acryloylpyridine with thiourea yielded thioxopyrimidine, which was treated with chloroacetic acid to yield thiazolopyrimidine. An arylmethylene derivative was prepared by reacting thiazolopyrimidine with indole-3-carboxaldehyde or by reacting thioxopyrimidine with indole-3-carboxaldehyde and chloroacetic acid in one step. The pharmacological screening showed that many of these obtained compounds have good analgesic and anticonvulsant activities comparable to Valdecoxib^? and Carbamazepine^? as reference drugs.     

The Rearrangement of 2—Benzothiazolylthioacetyl Hydrazide in Synthesis of s—Triazolo[3,4—b]benzothiazole—3—thiol

The rearrangement reaction of 2-benzothiazolylthioacetyl hydrazide 1 with potassium hydroxide and carbon disulfide in ethanol to produce s-triazolo [3,4-b] benzothiazole-3-thiol 3 was described. 3 also can be obtained from 2-benzothiazolylhydazine 2 and the two methods for getting 3 were compared. Mannich reaction of compounds 3 was reported too.     

Diastereoselective Synthesis of <Emphasis Type="Italic">cis</Emphasis>-2,6-Disubstituted Perhydro-4-pyranones Using Elevated Pressure Hydrogenation

Summary. A diastereoselective strategy for the synthesis of γ-pyrons was developed, starting from the Mg diacetonedicarboxylate complex. Initial cyclization with suitable anhydrides or acid chlorides, followed by hydrolytic decarboxylation leads to 2,6-disubstituted pyrans. Elevated pressure hydrogenation using Pd/C affords the title compounds in high diastereoselectivity. Scope and limitations of the method are outlined on selected examples.     

Lipase-catalyzed hydrolysis of methyl-3-phenylglycidate

Large amount of facts indicated that enantiomers were different from each other in biological activity, physiological activity and toxicity in clinical applications1. It resulted in the increase of interest on preparation of chiral drugs. Optical active 3-phenylglycidic ester, especially (2R,3S)-methyl 3-phenylglycidate is an important starting material for production of many chiral drugs, such as taxol, (2R,3S)-diltiazem etc2,3.For the above purpose, a series of lipases were screened. Final…     

The Effect of Ionic Liquids on the CaCO3 Crystal Growth

In this paper, the effect of ionic liquids on the CaCO3 crystal growth has been studied for the first time. The obtained CaCO3 crystals were charactcred by the X-ray diffraction and scanning electron micrographs. The results showed that the control ability of ionic liquids for CaCO3 crystals growth was dependent on the counter anion very much.     

Effect of Reaction Media on Photoreaction of Provitamin D_3

IntroductionThe photochemistry of provitamin D3 (Pro) has been studied extensively in many years1-4. As shown in Scheme 11, irradiation of provitamin D3 in organic solvents results in its photoisomerization to previtamin D3 (Pre). Previtamin D3 can be thermally transferred into vitamin D3 (VD3), which is of commercial interests. However, previtamin D3 also undergoes the photochemical back reaction leading to the regeneration of provitamin D3 and the photoisomerization resulting in the und…     

STUDY ON BIODEGRADABILITY OF POLY (3-HYDROXYBUTYRATE-co-3-HYDROXYVALERATE)/ORGANOPHILIC MONTMORILLONITE NANOCOMPOSITES

1. INTRODUCTION Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) has been recognized as apotential environment-friendly substitute for traditional plastics. The structure, mechanicalproperties and biodegradability of PHBV as biodegradable plastic have been reported by many groups [1-3]. However, PHBV presents some problems, such as high cost, slow crystallization rate, relatively difficult processing and high degree of crystallinity. Therefore, it is difficult to use PHBV widel…     

Determination of the enantiomers of 3-tert.-butylamino-1,2-propanediol by high-performance liquid chromatography coupled to evaporative light scattering detection

A method for the separation and quantitation of the enantiomers of 3-tert.-butylamino-1,2-propanediol by high-performance liquid chromatography and evaporative light scattering detection has been developed. Separation of the enantiomers was performed in normal-phase liquid chromatography on a Chiralpak AS chiral stationary phase. The influence of the gas nature, gas pressure and temperature of the drift tube of the evaporative light scattering detector on the detection sensitivity was investigated. The method was validated in terms of linearity, limit of quantitation, accuracy and precision. The enantiomeric excess of (S)-3-tert.-butylamino-1,2-propanediol, used for the industrial synthesis of (S)-timolol, was measured from 0 to 94%.     

Synthesis of 1,7-Bis(4-hydroxyphenyl)-3-hydroxy-1,3-heptadien-5-one

l,7-Bis(4-hydroxyphenyl)-3-hydroxy-1,3-heptadien-5-oneIIwagfirstlyisolatedfromtheseedsofAIPiniablepharocalyxK.Schum.(Zingiberaceae)asanoveldiarylheptanoid.Meanwhile,l,7-his(4-hydroxyphenyl)-3-hydroxy-l,3,6-heptatTien-5-one2,aknowndiarylheptanoid,wasisolatedaswell.Therecentpublication'reportedthatIstronglyinhibitedtheaggregationofplateletinducedbycollagen,arachidonicacidandadenosinediphosphate.AdditionalresearchZprovedthat2couldactasaninhibitoroftheHIV-1integrase.Byourfindings,thesynthesi…     

Synthesis and Antibacterial Activity of Some Substituted 3-(Aryl)- and 3-(Heteroaryl)indoles

Summary. A synthesis of 3-(4-methoxycarbonyl-2,6-dinitrophenyl)indole, its 2,6-diamino analog, and 3-(2-amino-4-trifluoromethyl-6-nitrophenyl)indole is described. 4-(Trifluoromethyl)phenyl derivatives exhibit higher antibacterial potency than the former 4-(methoxycarbonyl)phenyl homologs, while 3-(4-trifluoromethyl-2-nitrophenyl)indole was the most active agent in the series, with MIC ≈ 7 μg/cm³ against E. coli and S. aureus.     

Synthesis of Some Novel 2,6- Dimethoxyhydroquinone-3- mercaptoacetyl-peptide Conjugates as Potential Antitumor Agents

2, 6 - D imethoxyhydroquinon e - 3 -mere aptoac et ic ac id (D M Q -MA) I -3 is a syntheti cderivative of 2, 6 - d imethoxyp -b enzoqu inone (D M Q )#, whi oh is a n atUral fermentedproduct of wheat germ and was found to have a wide spectrUm of cytotoxicity againstvarious tUmor cell lines under the synergistic activation of L-ascorbic acid as reported byG.A.Szents. Owing to the very low aqueous solubility of DMQ, which is an apparentdisadvantage for the development as a vaccine, we prep…     

Theoretical study on the reaction mechanism of(CH_3)_3CO+CO

The global environment pollution includes pho-tochemical smog, acid rain and stratospheric ozonedepletion. The short-lived species/radicals in atmos-phere are closely related to these phenomena. Theshort-lived species/radicals bring the photochemicalsmog,…     

Determination of the stereochemistry of gamma-butyrolactones by DPFGSE-NOE experiments

The stereochemistry of gamma-butyrolactons tetrahydro-6a-phenylfuro[3,4-b]furan-2(3H)-one (1), 1,4,5,9b-tetrahydro-3a-methylnaphtho[2,1-b]furan-2(3aH)-one (2), 1,4,5,9 b-tetrahydro-3a-methylfuro[2,3-c]quinolin-2(3aH)-one (3) and hexahydro-furo[3,2-c]benzofuran-2-one (4) was studied using DPFGSE-NOE experiments. Compounds 1-3 contain two stereocenters, while 4 contains three. Both (1)H and (13)C spectra showed a single diastereomer of all the compounds. Routine 2D experiments (DQF)-COSY, HMQC/HSQC, and HMBC were used to assign (1)H and (13)C spectra completely. Diastereotopic methylene protons with resolved (1)H NMR signals as well as protons of cyclohexane served as references for the construction of the spatial arrangement in the molecules. NOE contacts between protons attached to the stereocenter and the diastereotopic protons were thus used to determine the configuration of the molecules. Vicinal coupling constants (3)J assisted the assignment of the conformational arrangement of the cyclohexane ring of 4.