Oxidation of myrtenol to myrtenal epoxide in a porphyrin-based photocatalytic system - A novel terpene alcohol derivative with antimicrobial and anticancer properties.

Biomimetic catalysis using porphyrins enables gentle oxidation of terpenes with molecular oxygen and light. This study explores the photooxidation of (-)-myrtenol under visible light to synthesize new terpenoid products with promising biological activity. Among the porphyrins tested, tetraphenylporphyrin (HTPP) exhibited the highest catalytic efficiency and stability in chloroform, producing myrtenal epoxide (ME) as the main product (with a molar conversion of myrtenol of 66.

Parametric Modelling of the Crystalline Microstructure of the MCM41-Type Mesoporous Silica Modified with Derivatives of Alkyls.

A siliceous material in which a framework order was established with a surfactant with sixteen carbon atoms in alkyl chains, MCM-41-C16, was synthesised, surface-modified, and tested regarding the selected physical properties. The pristine material was extracted in an acidic aqueous alcohol and then lined with different surface groups. The properties of four adsorbents were investigated using XRD, X-ray photoelectron spectroscopy, and N2 physisorption techniques.

Luminescent Hybrid BPA.DA-NVP@EuL Materials: In Situ Synthesis, Spectroscopic, Thermal, and Mechanical Characterization.

A series of homogeneous hybrid BPA.DA-NVP@EuL materials were obtained through an in situ approach where the luminescent dopant was formed at the molecular level with different contents (0.1; 0.

Qualitative and Quantitative Evaluation of Rosavin, Salidroside, and p-Tyrosol in Artic Root Products via TLC-Screening, HPLC-DAD, and NMR Spectroscopy.

Artic root is a well-known plant adaptogen with multipotential pharmacological properties. Thin-layer chromatography (TLC)-screening followed by diode-array high-performance liquid chromatography and nuclear magnetic resonance spectroscopy proved to be a reliable and convenient method for the simultaneous determination of the quality of various herbal raw materials and supplements. This combination allowed for comparing and differentiating arctic root samples as well as defining their authenticity.

Sordarin- An anti-fungal antibiotic with a unique modus operandi.

Fungal infections cause serious problems in many aspects of human life, in particular infections in immunocompromised patients present serious problems. Current anti-fungal antibiotics target various metabolic pathways, predominantly the cell wall or cellular membrane metabolism. Numerous compounds are available to combat fungal infections, but their efficacy is far from satisfactory and some of them display high toxicity.

Stability of stevioside in food processing conditions: unexpected recombination of stevioside hydrolysis products in ESI source.

Stevioside is the main and the sweetest glycoside of stevia plant. It is attractive as a natural sweetener to diabetics and others on carbohydrate-controlled diets. This paper discusses the stability of stevioside under food processing conditions.

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides.

β-Hydroxyalkylphosphine sulfides undergo [1,3]- or [1,4]-sulfur atom phosphorus-to-carbon migration in the presence of Lewis or Brønsted acids. The direction of sulfur atom migration depends on the type of acid used for the reaction. In the presence of a Brønsted acid, mainly [1,3]-rearrangement is observed, whereas a Lewis acid catalyzes the [1,4]-sulfur migration.

Pd-catalyzed intramolecular addition of active methylene compounds to alkynes with subsequent cross-coupling with (hetero)aryl halides.

We report an efficient protocol for tandem Pd-catalyzed intramolecular addition of active methylene compounds to alkynes, followed by subsequent cross-coupling with (hetero)aryl bromides and chlorides. The reaction proceeds under mild conditions, providing excellent functional group tolerance, including unprotected OH, NH groups, enolizable ketones, or a variety of heterocycles. Mechanistic studies point towards a catalytic cycle involving oxidative addition, intramolecular nucleophilic addition to the Pd(ii)-activated alkyne, and reductive elimination, with 5- cyclization being the rate limiting step.

Synthesis and Electrochemical and Spectroscopic Characterization of 4,7-diamino-1,10-phenanthrolines and Their Precursors.

New approaches to the synthesis of 4,7-dichloro-1,10-phenanthrolines and their corresponding 9-carbazol-9-yl-, 10-phenothiazin-10-yl- and pyrrolidin-1-yl derivatives were developed. Their properties have been characterized by a combination of several techniques: MS, HRMS, GC-MS, electronic absorption spectroscopy and multinuclear NMR in both solution and solid state including N CP/MAS NMR. The structures of 5-fluoro-2,9-dimethyl-4,7-di(pyrrolidin-1-yl)-1,10-phenanthroline (5d), 4,7-di(9H-carbazol-9-yl)-9-oxo-9,10-dihydro-1,10-phenanthroline-5-carbonitrile (6a) and 4,7-di(10H-phenothiazin-10-yl)-1,10-phenanthroline-5-carbonitrile () were determined by single-crystal X-ray diffraction measurements.

Feruloyloacetone can be the main curcumin transformation product.

Curcumin is a phenolic compound produced by some plants, among which Curcuma longa is the reachest in this principal curcuminoid. At elevated temperature curcumin degrades to trans-6-(4'-hydroxy-3'-methoxyphenyl)-2,4-dioxo-5-hexenal, vanillin, ferulic acid and feruloylmethane, however, the formation of feruloyloacetone ((5E)-6-(4-hydroxy-3-methoxyphenyl)hex-5-ene-2,4-dione) in the curcumin degradation process has not been reported yet. As results from experiments, even 28.

Formation of aqueous and alcoholic adducts of curcumin during its extraction.

Curcumin is a phenolic compound produced by some plants, among which Curcuma longa is the reachest in this principal curcuminoid. Curcumin is known from its lability, however, the structural curcumin transformations and the formation of hydroxy and alkoxy adducts has not been reported yet. The formation of the mentioned derivatives is favoured by an alkaline environment.

Intramolecular Nucleophilic Substitution of ω-Haloalkylphosphine Derivatives.

ω-Haloalkylphosphine derivatives undergo the intramolecular nucleophilic substitution reaction upon treatment with a strong base, yielding either cycloalkylphosphine derivatives or heterocyclic phosphine derivatives. The selectivity of the cyclization of (ω-haloalkyl)alkylarylphosphine derivatives depends strongly on the distance between the electrophilic and nucleophilic carbon atoms and the structure of the phosphorus moiety. The desymmetrization of dimethylphenylphosphine sulfide followed by haloalkylation and cyclization led to the enantiomerically enriched tertiary phosphine sulfide, possessing a cyclohexyl fragment at the phosphorus.

Stereoselectivity of Michael Addition of P(X)-H-Type Nucleophiles to Cyclohexen-1-ylphosphine Oxide: The Case of Base-Selective Transformation.

Michael addition of phosphorus nucleophiles to the unsymmetrically substituted tert-butyl(1,4-cyclohexadien-3-yl)phosphine oxide and its derivatives has been described. The addition proceeds with the formation of the mixture of two isomeric products with good yield and diastereoselectivity. The reaction of tert-butyl(cyclohexen-1-yl)methylphosphine oxide with phosphorus nucleophiles is base sensitive and might afford two epimers which differ at one chirality center.

Reduction of functionalized tertiary phosphine oxides with BH3.

A direct stereoselective conversion of tertiary hydroxyalkylphosphine oxides to the corresponding tertiary hydroxyalkylphosphine-boranes involving facile reduction of the P═O bond by BH3 under mild conditions has been developed. The unprecedented facility of reduction of the strong P═O bond by BH3, a mild reducing agent, has been achieved through an intramolecular P═O···B complexation directed by proximal α- or β-hydroxy groups present in the phosphine oxide structures. As established by two chemical correlations, the developed transformation of hydroxyalkylphosphine oxides into hydroxyalkylphosphine-boranes takes place with complete inversion of configuration at P.

Diastereoselective desymmetrization of diarylphosphinous acid-borane amides under Birch reduction.

Treatment of diarylphosphinous acid-borane amides possessing chiral amido functionality with an alkali metal solution in liquid ammonia induced a preferential dearomatization of one aryl substituent at phosphorus leading to the formation of non-equimolar amounts of diastereomers. Diastereoselectivity of dearomatization depends strongly on the structure of a chiral auxiliary.

Two-fold modification of the phenyl substituent in phenylphosphonic acid monoester monoamides.

Phenylphosphonic acid ethyl ester N,N-diethylamide was subjected to a double modification of its phenyl substituent through directed ortho-metalation followed by dearomatization of the aryl substituent under Birch reduction conditions. Application of the same methodology to a diastereomerically pure phenylphosphonic acid monoester monoamide led to the formation of P-stereogenic cyclohexadienyl-phosphonic acid derivatives. The method offers a simple and efficient modification of phenyl substituent in organophosphorus compounds.

Diastereoselective synthesis and coordination chemistry of enantiopure keto-bis-(2-phosphametallocene)s.

Enantiopure 2-(chlorocarbonyl)phosphametallocenes [MCp*(2-{COCl}-3,4-Me(2)-5-Ph-PC(4))] (M = Fe, Ru) react with phospholide anions to give 2-phosphametallocene-2'-acylphospholides K[MCp*(2-CO-2'-{3',4'-Me(2)-5'-PhPC(4)}-3,4-Me(2)-5-Ph-PC(4))] (M = Fe, Ru) and these have been converted into keto-bis-(2-phosphametallocene)s through reaction with [FeClCp*(tmeda)]; templation of this process with CuBr gives rise to the C(2)- (or pseudo-C(2)- when M = Ru) symmetric form of [{MCp*(3,4-Me(2)-5-Ph-PC(4))}(2)-2,2'-(CO)] (M = Fe, Ru; Fe, Fe) with high (>95%) diastereoselectivity. X-Ray structures of these ligands coordinated to [RuCp*Cl] and [PtCl(2)] centres show that the spatial orientation of the very flexible keto-bis-(2-phosphametallocene) structure is highly responsive to the coordination sphere of the chelated platinum or ruthenium centre.

Michael-type addition of secondary phosphine oxides to (1,4-cyclohexadien-3-yl)phosphine oxides.

Base-induced reaction between (1,4-cyclohexadien-3-yl)phosphine oxides and secondary phosphine oxides gives 3,4-bis(phosphinoyl)cyclohexenes and 2,3-bis(phosphinoyl)cyclohexenes through an in situ isomerization of one of the cyclohexadienyl double bonds and a subsequent Michael-type addition of the secondary phosphine oxide.

A comparison of phosphaferrocene and phospharuthenocene ligands in Rh+-catalysed enamide hydrogenation reactions: superior performance of the phospharuthenocene.

Enantiopure Cp*-substituted 3,4-dimethyl-5-phenylphosphametallocene-2-methanols (M=Fe, Ru) have been prepared from the corresponding 2-carboxy-(-)-menthylphospholide anion and elaborated into 2-CH(2)PPh(2) phosphametallocenes (13: M=Fe; 14: M=Ru) and 2-CH(2)PtBuR substituted phospharuthenocenes (R=tBu, Me). The crystal structures of complexes [Rh(1,5-cod)(eta(2)-L)](+)BF(4)(-) (L=13, 14) reveal significantly different aryl group configurations. Comparative studies of the hydrogenation of para-substituted N-acetylcinnamate esters with these pre-catalysts show a superior performance for the phospharuthenocene derivative in terms of both rate and enantioselectivity.

Resolution and stereochemistry of tert-butylphenylphosphinous acid-borane.

A combined use of ephedrine and cinchonine as resolving agents enabled facile resolution of racemic tert-butylphenylphosphinous acid-borane (1) into the two enantiomers in ca. 31-32% yield each. The resolved 1 served as a model substrate to study stereoselective synthetic transformations of phosphinous acid-boranes yielding optically active phosphinite-borane, boranatophosphinous-sulfonic anhydride, secondary phosphine-borane, tertiary phosphine-borane, secondary phosphine oxide, and phosphinic halides.