Simple and Efficient Method for the Protection of Hydroxyl Groups as 4-Methoxybenzyl Ethers

PMB ethers of alcohols are obtained in good yields and under mild conditions using the 4-methoxybenzyl N-allyl thiocarbamate and N-bromosuccinimide (NBS)/TfOH as the catalyst. The present method is very fast, simple, and efficient.     

Chloroglycidate Synthesis of a Precursor of Natural 3-Deoxy-D-manno-octulosonic Acid with Combined Protective Groups

A new oxo form of D-mannose with cyclohexylidene and benzyl protective groups is synthesized with the aim of adapting the chloroglycidate synthesis for natural 3-deoxy-D-manno-octulosonic acid. The sites of fixation of the protective groups were established by converting a model compound, 4-O-acetyl-2,3: 5,6-di-O-cyclohexylidene-aldehydo-D-mannose, into a known dicyclohexylidene-D-manno-furanose. The oxo form was reacted with methyl dichloroacetate to obtain a stereoisomeric mixture of chloroglycidates which were transformed into the corresponding pyruvate. The ketone and enol forms of the latter compound were isolated and separately characterized.     

4-(4-氨基苯基)-3-吗啉酮的合成

以乙醇胺为起始原料,通过环合、Goldberg藕联、还原,三步反应合成利伐沙班关键中间体4-(4-氨基苯基)-3-吗啉酮;该方法反应条件温和、生产成本低、绿色环保,具有良好的工业化前景。     

Synthesis of 2-methyl-3-(3,5-diallyl-4-hydroxyphenyl)-4-quinazolones as possible anticonvulsants

A series of 2-methyl-3-(3,5-diallyl-4-hydroxyphenyl)-4-quinazolones were prepared as possible anticonvulsants. All compounds were evaluated for their anticonvulsant activity against pentylene-tetrazol-induced seizures and their ability to potentiate sodium pentobarbital sleeping time in albino mice.     

Reactions of Polyhalopyridines. 17. Synthesis of 2-, 3-, and 4-Perfluoroalkylthiopolychloropyridines

2-, 3-, and 4-Perfluoroalkylthiopolychloropyridines have been synthesized using perfluoroalkylated thiol and disulfide derivatives of polychloropyridines via the thermal decomposition of Xe(II) bisperfluoroalkylcarboxylates. It was shown that their formation takes place from the starting thiols only through the formation of the disulfides. It was found that 3,4,5,6-tetrachloro-2-trifluoromethylthiopyridine reacts with potassium p-tolylthiolate with retention of the fluorine containing fragment and substitution of the chlorine atom in position 4 of the pyridine ring by the tolythio group.     

Use of Cleavable Coordinating Rings as Protective Groups in the Synthesis of a Rotaxane with an Axis that Incorporates More Chelating Groups Than Threaded Macrocycles

A new methodology allowing preparation of a linear “unsaturated” [3]rotaxane consisting of an axis incorporating more coordination sites than threaded rings was developed. It was based on the preliminary synthesis of a “saturated” [5]rotaxane consisting of a four‐chelating site axis threaded through four macrocyclic components, two of them being cleavable rings incorporating a lactone function and the two others being “secure” non‐cleavable rings. The stoppering reaction was based on click chemistry. Subsequently, cleavage and removal of the two lactone‐containing macrocycles from the [5]rotaxane in basic medium afforded the desired “unsaturated” [3]rotaxane in quantitative yield.     

1-Ethyl-1,4-dihydro-4-oxo-7-(pyridinyl)-3-quinolinecarboxylic acids. I. Synthesis of 3- and 4-(3-aminophenyl)pyridine intermediates

A series of substituted 3- and 4-(3-aminophenyl)pyridines has been prepared as intermediates for the synthesis of some 1-alkyl-1,4-dihydro-4-oxo-7-pyridinyl-3-quinolinecarboxylic acids. The Hantzsch, Hauser and other pyridine syntheses were used. 4-(3-Aminophenyl)pyridine was prepared via 3-(4-pyridinyl)-2-cyclohexen-1-one using the Semmler-Wolff reaction.     

Polyfunctional pyrazoles. 4. Synthesis of 3-[3-aryl-1-(2-ethoxycarbonyl)-4-pyrazolyl]acrylic and-propionic acids

3-(3-Aryl-4-formyl-1-pyrazolyl)propionic acids are converted by Knoevenagel condensation under conditions of microwave activation into 3-[3-aryl-1-(2-ethoxycarbonyl)-4-pyrazolyl]acrylic acids. Reduction of the latter with hydrazine hydrate in the presence of Raney nickel gives 3-[3-aryl-1-(2-ethoxycarbonyl)-4-pyrazolyl]propionic acids. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 686–690, May, 2006.     

Polyesters with Aromatic Groups in the Backbone from Reactions of 3- and 4-Bromomethylbenzoic Acids with Triethylamine

Abstract

Aromatic polyesters were obtained in relatively good yields (～ 70%) from reactions of 3- and 4-bromomethylbenzoic acids with tri-ethylamine in chlorobenzene. A copolymer was prepared in 58% yield by reaction of a 1:1 mixture of the two acids under similar conditions. The polyesters were characterized by IR, ¹H- and ¹³3C-NMR spectra, x-ray powder diffraction, DSC behavior, solution viscosity, and hydrolysis to the corresponding hydroxymethylbenzoic acids. Molecular weights were determined by ¹H-NMR endgroup analysis. Possible mechanisms for the reactions are discussed.     

Reactions of 3-nitro-2-trihalomethyl-2H-chromenes with C-nucleophiles. Synthesis of 3-nitro-4-(pyrazol-4-yl)-2-trihalomethylchromanes

The nucleophilic addition of acetylacetone and ethyl acetoacetate at the double bond of 3-nitro-2-trihalomethyl-2H-chromenes in the presence of NaH affords 2,3,4-trisubstituted chromanes containing the β-dicarbonyl fragment at position 4. The trans-trans configuration and the enol structure of the reaction products were confirmed by ¹H NMR spectroscopy and X-ray diffraction. Treatment of these compounds with hydrazine gives the corresponding 3-nitro-4-(pyrazol-4-yl)-2-trihalomethylchromanes. The reactions of 3-nitro-2-trihalomethyl-2H-chromenes with nitromethane and nitroethane in the presence of K₂CO₃ produce 1,3-dinitro derivatives of the chromane series. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1945–1955, November, 2006.     

Synthesis of substituted 2-ethyl-3-(4-hydrazinocarbonylphenyl)-4-quinazo-lones and 2-ethyl-3-(4-hydrazinocarbonylmethylphenyl)-4-quinazolones

Some substituted 2-ethyl-3-(4-hydrazinocarbonylphenyl)-4-quinazolones and 2-ethyl-3-(4-hydrazinocarbonylmethylphenyl)-4-quinazolones were synthesized and characterized by their sharp melting points, elemental analyses and spectral data.     

Synthesis of Polyphosphonates Containing 5—Flouro—N^1—furanyl—N^3—glyceroalkyl—uracil and Formyl Groups

A series of novel polyphosphonates containing 5-flouro-N^1-furanyl-N^3-glyceroalkyl-uracil and formyl groups was synthesized by the condensation of 3-(ω-(1′-furanyl-5-flourouracil-3-yl) alkoxy)-1,2-dihydroxy propane with phosphonyl dichloride. The products were characterized by IR,^1H NMR,^31P NMR, M,and elemental analysis. The results of bioassay show that compound 8a possesses potential anticancer activity.     

Synthesis and pharmacological evaluation of some 3-(4-methoxyphenyl)-2-substitutedamino-quinazolin-4(3H)-ones as analgesic and anti-inflammatory agents

A variety of novel 3-(4-methoxyphenyl)-2-substitutedamino-quinazolin-4(3H)-ones were synthesized by reacting the amino group of 2-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one with a variety of alkyl and aryl ketones. The starting material 2-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one was synthesized from 4-methoxyaniline. The title compounds were investigated for analgesic, anti-inflammatory and ulcerogenic index activities. While the test compounds exhibited significant activity, compounds 2-(1-methylpropylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A1), 2-(1-ethylpropylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A2) and 2-(1-methylbutylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A3) showed moderately more potent analgesic activity and the compound 2-(1-methylbutylidene)-hydrazino-3-(4-methoxyphenyl)-quinazolin-4(3H)-one (A3) showed moderately more potent anti-inflammatory activity when compared to the reference standard diclofenac sodium. Interestingly the test compounds showed only mild ulcerogenic potential when compared to aspirin.     

Synthesis of 4-(4-phenyl-3-pyrazolyl)-4H-1,2,4-triazoles

4-(4-PhenyI-3-pyrazolyl)-4H-1,2,4-triazoles and 4-phenyl-5-(4H-1,2,4-triazol4-yl)-3-pyrazolols were prepared by the reaction of formylhydrazine on α-phenyl-α-cyanoacetaldehydes and ethyl α-phenyl-α-cyanoacetates.     

Synthesis and Spectroscopic Properties of Cyclotriphosphazenes Containing 6-(4-Hydroxyphenyl)-2,2''-bipyridine Side Groups

Two novel cyclotriphosphazene derivatives containing 6-(4-hydroxyphenyl)-2,2'-bipyridine(hopbp)side groups,N_3P_3(dobp)_2(hopbp)_2(1)and N_3P_3(dobp)(hopbp)_4(2)(dobp=2,2'-dioxybiphenyl),were synthesized and characterized.These compounds display strong fluorescent emission both in solution and in solid state.Their absorption and emission spectra are sensitive to proton:the addition of HBF4 to the methanol and dichloromethane solution(9∶1,volume ratio)of compound 1 led to a red-shift from 350 to 460 nm for the emission spectrum,and the process was also characterized by isosbestic points of absorption spectra at 267,287 and 313 nm.     

固体酸SO2-4/ZrO2-MoO3催化合成富马酸二甲酯

在固体酸SO2-4/ZrO2-MoO3催化下,由马来酸酐和甲醇催化合成了富马酸二甲酯.探讨了催化剂用量,原料配比,反应时间对产率的影响.最佳反应条件为醇酸摩尔比为61,反应时间3 h,催化剂占反应物总质量的1.5%,产物收率在93%以上.     

2-(4-甲硫苯氧基)-3-(4-甲苯基)-4H-咪唑啉-4-酮衍生物的合成及杀菌活性(Ⅱ)

用烯基膦亚胺与4-甲苯基异氰酸酯、对甲硫苯酚的串联aza-Wittig反应合成了2-(4-甲硫基苯氧基)-3-(4-甲苯基)-4H-咪唑啉-4-酮衍生物.探讨了反应进行的条件和产物的波谱性质,提出了可能的环化反应机理.生成的环化产物均为新的化合物,其结构经元素分析、IR、1H NMR和MS确证.并探讨了所合成的新型杂环化合物的生物活性,结果表明部分化合物表现出良好的抑菌活性,其中3f的活性最好,在质量分数为5×10-5浓度时,对稻瘟菌和苹果轮纹菌的抑制率均达到100%.