Synthesis of 5-substituted-3-[(2′S,3′S)-3′-hydroxy-2′-hydroxymethyltetrahydrofuran-3′-yl]-1,2,4-oxadiazoles and their epimers

5-Phenyl-3-[(2′R,3′S)-3′-hydroxy-2′-dimethoxymethyltetrahydrofuran-3′-yl]-1,2,4-oxadiazole 10a and its epimer 11a, 5-methyl-3-[(2′R,3′S)-3′-hydroxy-2′-dimethoxymethyltetrahydrofuran-3′-yl]-1,2,4-oxadiazole 10b and its epimer 11b were synthesized from cyanohydrin benzoates 8a, 9a and cyanohydrin acetates 8b, 9b, respectively, by treatment with hydroxylamine in methanol via intramolecular transacylation and subsequent cyclization of the corresponding amidoximes. Hydrolysis and reduction of the dimethoxymethyl groups in the above compounds gave the desired compounds 12a, 13a, 12b and 13b.     

A Practical Synthesis of (S)-(+)-2-(6-methoxyl-2-naphthyl) propionic Acid

a-Arylpropionic acids are an important class of non-steroidal anti-inflammatory agents1,2. The therapeutic efficacy of this class of drugs is well demonstrated by the introduction and extensive use of more than a dozen compounds exemplified by ibuprofen, naproxen, ketoprofen and flurbiprofen etc. However, in recent years the use of enantiomerical pure drugs in chemotherapy is becoming almost mandatory for enhancing specificity of drug action and reducing the toxicity. This awareness led to …     

Synthesis and structural characterization of camphanates of (−)-(2S3S,3S) and (+)-(2S,3R)-4-Phenyl-3-bromo-2-butanol diastereoisomers

The X-ray crystal structures of (–)-syn-4-phenyl-3-bromo-2-butyl camphanate (I) and (+-anti-4-phenyl-3-bromo-2-butyl camphanate (II) have been determined. Thesyn diastereoisomer of bromohydrin has the (2S,3S) absolute configuration whereas theanti diastereoisomer has the (2S,3R) absolute configuration. The crystallized derivatives I and II have been obtained by the reaction of each stereoisomer of bromohydrin, synthesized by reduction with baker's yeast, with (1S)-camphanic chloride. Crystal data: (I) C₂₀H₂₅BrO₄:M _w: 409.32; orthorhombic,P2₁2₁2₁;a=11.245(3),b=12.086(1),c=14.512(4) å; Z=4; finalR=0.053 for 1819 observed reflections. (II) C₂₀H₂₅BrO₄;M _w=409.32; monoclinic, P2₁;a=11.352(1),b=6.378(1),c=14.255(2) å,=110.38(1);Z=2; finalR=0.045 for 1672 observed reflections.     

Synthesis and Crystal Structure of(p-{2-[p-(5′-Phenyl-1′,3′,4′-oxadiazole-2′-yl)-phenyl]-vinyl}-phenyl)-di-p-tolyl-amine

The crystal of the title compound (C36H29N3O,Mr = 519.62) has been prepared and structurally determined by X-ray single-crystal diffraction. It crystallizes in triclinic P ī space group with the crystal cell parameters: a = 12.544(4), b = 14.112(4), c = 17.770(5)A, α = 96.150(6), β = 106.112(5), γ = 107.156(5)°, V = 2825.7(14) ?3, Z = 4, Dc = 1.221g/cm3, μ(MoKα) = 0.074 mm-1 , F(000) = 1096,the final R = 0.0747 and wR = 0.1632 for 4713 observed reflections with I >2σ(I). The E-stereochemistry of the title compound can be confirmed by the result of the X-ray diffraction analysis.     

Synthesis and Crystal Structure of 3-(Pyrrole-2′-carboxamido)propanoic Acid·(1/2)H_2O

1 INTRODUCTION Pyrrole and its derivatives have attracted much attention due to their chemical properties as well as biological activities[1]. They have been widely used to produce pharmaceutical, essences, biochemicals, etc. It has been found that a great number of pyrrole derivatives present antitumor and antiviral activi- ties[2 ~ 5]. During our searches for bioactive com- pounds, a series of pyrrole derivatives were synthe- sized[6, 7]. We report here the synthesis of 3-(pyrrole- 2?-…     

Synthesis and Crystal Structure of 4-Phenyl-5-(1′- t-butyl-5′-methyl-4′-pyrazolyl)-1,2,4-triazol-3-thione

The crystal structure of 4-phenyl-5-(1′-t-butyl-5′-methyl-4′-pyrazolyl)-1,2,4-triazol- 3-thione 5 (C16H19N5S, Mr = 313.42) has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/c with a = 6.680(2), b = 27.44(1), c = 9.388(4)(A。), β = 106.738(6)°, V = 1648(1)(A。)3, Z = 4, Dc = 1.263 g/cm3, μ= 0.200 mm-1, F(000) = 664, R = 0.0608 and wR = 0.1176. The results confirmed that 5 can be assigned to the thione tautomeric form.     

Synthesis of (3S,5R)-cis- and (3S,5S)-trans-3,5-Dimethylvalerolactones and Their Conversion to Biotransformation Products of (S)-5-Ethyl-5-(2′-pentyl)barbituric Acid

(R,S)-5-Ethyl-5-(2′-pentyl)barbituric acid (I)^1,2 is metabolized in vivo to give all four possible optical isomers of 5-ethyl-5-(3′-hydroxy-1′-methylbutyl)barbituric acid (II). ^3,4 From metabolism studies of pure (1′S)- I and (1′3)-I, Palmer and co-workers^4,5 were able to determine the relative amounts of each of the four isomers formed. These studies showed that (1′S)-I gave mainly one enantiomer of (1′S)-II, whereas (1′R)-I gave approximately equal amounts of both (1′R)-II enantiomers.     

Synthesis and Crystal Structure of 4-（4,6-Dimethoxylpyrimidin-2-yl）- 3-thiourea Carboxylic Acid Ethyl Ester

4-（4,6-Dimethoxyl-pyrimidin-2-yl）-3-thiourea carboxylic acid ethyl ester was synthesized by the reaction of 2-amino-4,6-dimethoxyl pyrimidine, potassium thiocyanate and methyl chloroformate in ethyl acetate. Single crystals suitable for X-ray measurement were obtained by recrystallization with the solvent of dimethyl formamide at room temperature. The crystal structure was determined by X-ray diffraction analysis. Crystallographic data： C10H14N4O4S, M, = 286.31, monoclinic, space group C2/c with a = 2.5309（3）, b = 0.67682（6）, c = 1.74237（19） nm, β = 114.744（3）°, V= 2.7106（5） nm3, Dc = 1.403 g/cm3, p = 0.225 mm-1, F（000） = 1200, Z= 8, R= 0.0514 and wR= 0.1529.     

Synthesis and Crystal Structure of N′-(4-fluorobenzylidene)-2-(1H-1,2,4-triazole-1-yl)acetohydrazide

IntroductionBoth triazole derivatives and Schiff base have beenreported to possess significant antifungal[1—3]and plantgrowth regulatory activities[4—6].Triazole drugs are alsovery common in the medical field,which has given animmense impetus to the res…     

Asymmetric Hydrogenation Synthesis of (S)-(+)-2-(6′-methoxyl-2-naphthyl) propionic Acid by Cinchona Modified Pd(0)-α-FeOOH Catalyst

During the past decades enormous progress was made in asymmetric catalytic synthesis, an well-known example is BINAP1, the chiral hydrogenation synthesis of S-(+)-naproxen catalyzed by BINAP-Ru dicarboxylate complexes provides excellent enantioselectivity (up to 99% ee) and good chemical yield (92%), however the pressures is relatively high (135-150 atm) and the (S)-BINAP-Ru(III) complex is very expensive. This problem may present a practical limitation. In recent years new methodolo…     

Synthesis, Crystal Structure and Biological Activities of N′-(4-Methoxybenzylidene)-2-(1H-1,2,4-triazol-1-yl)acetohydrazide

IntroductionBoth triazole derivatives and Schiff base are repor-ted to possess significant antifungal and plant-growthregulatory activities[1—6].Further,triazole drugs are al-so very common in the medical field.These give a greatimpetus to the research for potential pharmacologicallyactive Schiff base containing triazole.In order to search for newtriazole compounds withhigher biological activity,the title compound was syn-thesized and its biological activities were tested.Also,its structure…     

Synthesis, Crystal Structure and Biological Activities of N′-(4-Methoxybenzylidene)-2-(1H-1,2,4-triazol-1-yl)acetohydrazide

The title compound, N′-(4-methoxybenzylidene)-2-(1 H -1,2,4-triazol-1-yl)acetohydrazide, was synthesized and its structure was confirmed by means of IR, MS, 1H NMR and elemental analysis. The single crystal structure of the title compound was determined by X-ray diffraction. The preliminary biological test shows that the synthesized compound has a low antifungal activity.     

Synthesis and Crystal Structure of 5-N-i-Propyl-2-(2′-nitrobenzenesulfonyl)-glutamine

IntroductionAcetohydroxy acid synthase(AHAS) is a perfecttarget for the design of environmentally benign herbi-cides because it is a key enzyme that is absent in ani-mals but is important for the biosynthesis of branched-chain amino acids in plants[1,2]. …     

Facile Synthesis of 2-(4-Hydroxybiphenyl-3-yl)-1H-indoles from Anilines and 5′-Bromo-2′-hydroxyacetophenone

2-Arylindoles are attractive scaffolds because they are found in many pharmacologically active molecules. In this study, we describe the facile synthesis of diverse 2-(2-hydroxyphenyl)-1H-indoles from anilines and 5′-bromo-2′-hydroxyacetophenone in two steps using palladium-catalyzed indole cyclization as a key reaction. The indole cyclization was primarily controlled by the substituent properties of anilines. Suzuki-coupling reactions of 2-(5′-bromo-2′-hydroxyphenyl)-1H-indoles with arylboronic acids provided the corresponding 2-(4-hydroxybiphenyl-3-yl)-1H-indoles in moderate yield.     

Synthesis and Crystal Structure of 2-[（2-Chloropyridin-4-yl）oxy]-3,3-diphenyl-3-methoxypropionic Acid

The title compound was synthesized and its crystal structure was determined by single-crystal X-ray diffraction.The crystal is of orthorhombic system(C21H18ClNO4,Mr = 383.81),space group Pca21 with a = 13.913(3),b = 10.273(2),c = 26.488(5),V = 3786.1(13) 3,Z = 8,Dc = 1.347 g/cm3,F(000) = 1600,μ = 0.228 mm-1,the final R = 0.0550 and wR = 0.1278 for 5065 observed reflections(I > 2σ(I)).The title compound in a racemic form was found to exist as a mixture of two enantiomers in an equal ratio in the unit cell.The intermolecular hydrogen bonds link the molecules in a head-to-end manner to generate an infinite chain.     

Synthesis and biological activity of the (−)-(2R,3S,4S)-3-azido-4-methoxy-2-(1′S-methoxy-2′-azido)ethyl-thiolane

A stereospecific ring contraction reaction, promoted by NaN₃, was detected starting from a thiepane derivative obtained from d-sorbitol, an inexpensive alcohol sugar. The major polyfunctionalized thiolane derivative obtained was investigated as a potential glycosidase inhibitor.     

Synthesis,Crystal Structure and Antifungal Activity of a New Zn(Ⅱ) Complex Based on 4-(5-(Pyridin-3-yl)-4H-1,2,4-triazol-3-yl) Benzoic Acid

A new complex[Zn(3,4-APT)2(H2 O)4]·8 H2 O(1,3,4-HAPT=4-(5-(pyridin-3-yl)-4 H-1,2,4-triazol-3-yl)benzoic acid)has been prepared and characterized by elemental analysis,X-ray single-crystal diffraction analysis,thermogravimetric analysis and infrared spectrum analysis.Theoretical calculation based on density functional theory(DFT)is also employed to explicate frontier orbitals of 3,4-HAPT.X-ray single-crystal diffraction analysis reveals that 1 belongs to the triclinic system,space group P1 with a=7.5123(3),b=8.6745(3),c=15.2074(6)?,α=78.469(1),β=87.387(1),γ=65.448(1)°,V=882.42(6)?,Z=1,D_c=1.528 g·cm^–3,μ=0.780 mm^–1,M_r=812.09,F(000)=424,the final R=0.0401 and wR=0.1136.Zn(II)ion is coordinated by two N atoms from two 3,4-HAPT as well as four O atoms from four coordinated water molecules,forming a 0D motif with distorted octahedral coordinated geometry.The adjacent 0 D units are linked into a 3 D supramolecular structure through hydrogen bonding interaction.In addition,complex 1 exhibits better antifungal activity against Colletotrichum gloeosporioides Penz than the ligand and metal salt by MIC,MBC tests and Kirby-Bauer disc diffusion method which exhibit potential application in the antifungal fields.     

Synthesis and Crystal Structure of 4-（4,6-dimethoxyl -pyrimidin-2-yl）-3-thiourea Carboxylic Acid Methyl Ester

1 INTRODUCTION Pyrimidinyl thioureas have been studied for many years because of their broad antibiosis and sterilibza- tion properties. Recent years’ study shows that pyri- midinyl thioureas not only can be used to kill insects and adjust plant growth, but also have anti-viral ac- tivities[1, 2]. From our early quantum study on these compounds, we find that they have several active cen- ters and can form polyligand complexes with metals easily[3]. These complexes are widely used as ant…     

Synthesis of 2-(hydroxyphenylamino)- and 2-(aminophenylamino)-4-methylquinolines and N,N′-bis(4-methylquinolin-2-yl)benzenediamines

2-(Hydroxyphenylamino)- and 2-(aminophenylamino)-4-methylquinolines and N,N′-bis(4-methylquinolin-2-yl)benzenediamines were synthesized by reactions of 2-chloro-4-methylquinolines with o-, m-, and p-aminophenols and o-, m-, and p-phenylenediamines.     

Facile and Efficient Regioselective Synthesis of 1-(3′-Substituted Quinoxalin-2′-yl)-3-aryl/heteroaryl-5-methylpyrazoles

This report describes an efficient and practical approach for regioselective synthesis of 1-(3′-substituted quinoxalin-2′-yl)-3-aryl/heteroaryl-5-methylpyrazoles (3a–j). Reaction of 2-chloro-3-substituted quinoxalines (1) with 3(5)-methyl-5(3)-aryl-1H-pyrazoles (2) in the presence of sodium hydride furnished the title compounds in excellent yields with good levels of regioselectivity. The present protocol is superior to the existing method, which yielded a mixture of regioisomeric pyrazoles (I, II) and triazolo[4,3-a]quinoxalines (III).

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