First Synthesis and Properties of Calix[4]arene with Two Alternately Arranged Phloroglucinols and Two p-tert-Butylphenols

The Calix[4]arene 1 including two alternately arranged phloroglucinols and p-tert-butylphenols was synthesized via the “3+1” coupling procedure, and its pKa values were estimated to be 3–4 and 7.5, while those of the other six phenolic hydroxyls were approximately 11. Its UV–vis spectrum at pH 11 and ¹H and ¹³C NMR spectra in NaOD-D₂O solution (pH 12.8) showed a dramatic change like those of the phloroglucinol when compared to those in acidic or neutral solution, which suggests a change in the phloroglucinol moiety to the keto-form. During the solvent extraction for alkali metal species using 1, Li⁺ was only extracted in the low yield of 15% at pH 11. The cyclic voltammetry study of 1 was used to compare it with the phloroglucinol and p-tert-butylphenol. The redox potential of the corresponding two phloroglucinols was observed in 1.     

恶魔背后的天使——杜冷丁的故事

介绍了杜冷丁先生的基本性质及其恶魔面和天使面,以及它在医学各领域中的作用。详细说明了它与其他药物混合使用时的效果,以及当今社会盲目地对杜冷丁等药物过度利用带来的弊端。     

Temperature-controlled Cascade Reaction of Phloroglucinoltribenzyl Ether Promoted by Trifluoroacetic Anhydride and Trifluoroacetic Acid

We report the first trifluoroacetic anhydride-and trifluoroacetic acid-promoted cascade reaction with phloroglucinoltribenzyl ether and carboxylic acid as starting materials. By simply varying the temperature of systems containing the same starting materials, different products were produced in high yields. A three-step consecutive reaction process was also proposed.     

间苯三酚-甲醛气凝胶及其碳气凝胶的制备与表征

 以间苯三酚(P)和甲醛(F)为原料,经溶胶-凝胶、溶剂交换、超临界干燥和碳化等过程制备出了间苯三酚-甲醛气凝胶(PF)及其碳气凝胶(CPF)。测试结果表明气凝胶具有比较高的比表面积、是一种连续nm级3维网络结构的多孔材料;碳化后密度和平均孔径增大,比表面积基本无变化,且仍然维持气凝胶的网络结构。催化剂摩尔比决定气凝胶的微观结构,反应物质量分数控制着气凝胶密度。通过优化制备条件,可以制备出能满足惯性约束聚变(ICF)靶需要的不同结构和不同密度的气凝胶。     

Euphoractone,a cytotoxic meroterpenoid with an unusual ent-abietane-phloroglucinol skeleton,from Euphorbia fischeriana Steud.

A novel meroterpenoid,euphoractone(1),was isolated from the extracts of the roots of Euphorbia fischeriana Steud.Its structure was determined by spectroscopic methods and X-ray crystallography.1 possesses an unusual ent-abietane-phloroglucinol skeleton.The plausible biosynthetic pathway for 1 was proposed.1 showed inhibitory activities against human lung cancer H23 and H460 cells with the IC₅₀values of 21.07±3.54 and 20.91±4.07 μmol/L.     

Synthesis and molecular structure of potassium 3,5-dinitrophloroglucinolsulfonate monohydrate

A novel coordination polymer, potassium 3,5-dinitrophloroglucinolsulfonate monohydrate ([K(DNPGS) (H₂O)] _n ), was synthesized by the reaction of 3,5-dinitrophloroglucinolsulfonic acid (DNPGS) with potassium hydroxide in aqueous solution and the structure was determined by elemental analysis, IR and x-ray single-crystal diffraction analysis. The crystal belongs to orthorhombic system with space group Pca2(1). Its unit cell parameters are as follows: a=1.0819(14) nm, b=0.56563(11) nm, c=1.8979(4) nm; V=1.1615(4) nm³, Z=4, D _c =2.015 g/cm³, F(000)=712, chemical formula C₆H₅KN₂O₁₁S and M _r =352.28. The bridging potassium ion coordinates with nine oxygen atoms originating from the sulfonic groups, phenolic hydroxyl groups, nitro-groups of five DNPGS⁻ anions and two water molecules simultaneously, and a stable cross-linked three-dimensional network is formed. The thermal analysis of the complex show that it dehydrates at about 100°C, and only has an intense exothermic process at 204.2–245.2°C with exothermic enthalpy 1383.4 kJ mol⁻¹.     

Supercritical extraction of phloroglucinol and benzophenone derivatives from Hypericum carinatum: quantification and mathematical modeling

The aerial parts of Hypericum carinatum (Guttiferae) were extracted with supercritical carbon dioxide under constant temperature (40, 50 or 60°C) and gradual pressure increase (90, 120, 150 and 200 bar) aiming at the recovery of enriched fractions containing uliginosin B, cariphenone A and cariphenone B, compounds of pharmaceutical interest. The yields of these substances were determined by high‐performance liquid chromatography and compared with those obtained with n‐hexane maceration. The supercritical‐fluid extraction showed higher selectivity than the conventional solvent extraction method. After defining 40°C and 90 bar as the best conditions to obtain the target compounds, a mathematical model was used for the extraction process and a good correlation was achieved with the experimental data.     

Spectrophotometric Determination of Formaldehyde

ABSTRACT

A simple and very sensitive method for the determination of formaldehyde is described. Formaldehyde reacts with phloroglucinol in acid medium producing a yellow dye with λ_max at 435nm. The method is useful for the determination of formaldehyde in the range 0-2.5μg in an overall volume of 10mL with molar absorptivity of 8.3 × 10⁴1 mol^?1 cm^?1 and a relative standard deviation of 2% at 1.5μg level (n=10).     

Specific Determination of Catechol

Abstract

The chromogenic reaction of catechol with phloroglucinol is improved by substitution of an alcoholic media for an aqueous one. From 0.05–1.1 ppm of catechol can be assayed, with a standard deviation of ± 0.01.     

Buffer-induced, selective mono-C-alkylation of phloroglucinol: application to the synthesis of an advanced intermediate of catechin

A straightforward mono-selective and C-specific alkylation of phloroglucinol with activated alkyl halides is presented. The use of water as solvent limits the amount of over-alkylated by-products. Provided some minor changes in the experimental conditions, hydrophobic cinnamyl halides can also be reacted, thus giving a direct access to advanced intermediates of natural flavonoids.