Kinetics of the beta-scission in alkyl radical reaction class was studied using the reaction class transition state theory (RC-TST) combined with the linear energy relationship (LER) and the barrier height grouping (BHG) approach. All necessary parameters were derived from first-principle density functional calculations for a representative set of 21 reactions. ...

Transformation of {2-[(acetyloxy)methyl]cyclohexa-2,4-dien-1-yl}methyl acetate to various carbasugars is described. Photooxygenation of a cyclohexadiene derivative gave a bicyclic endoperoxide, which was reduced with thiourea to the diol diacetate. Epoxidation of the remaining double bond followed by epoxide ring opening and hydrolysis of the acetate groups gave one of the target hexols. ...

A stereospecific photochemical ring contraction was used as the key step in the first total synthesis of the marine pseudopteranyl diterpene 11-gorgiacerol and its 11-epimer. The synthesis allowed the correction of the configurations that had been misassigned in the literature. In addition, some novel pseudopteranyl derivatives have been made.

ABSTRACT: BACKGROUND: The desulphurization of dibenzothiophene (DBT), a recalcitrant thiophenic fossil fuel component by Serratia marcescens (UCP 1549) in order for reducing the sulphur content was investigated. The study was carried out establishing the growth profile using Luria Bertani medium to different concentrations of DBT during 120hours at 28oC, and ...

We have previously reported the formation of a glutathionyl conjugate of the active metabolite (AM) of clopidogrel and the covalent modification of a cysteinyl residue of human cytochrome P450 2B6 in a reconstituted system (Zhang et al, Mol. Pharmacol. 80:839-847 (2011)). In this work, we have extended our studies of ...

An efficient new method was developed to construct multisubstituted 4, 5-dihydro-1H-azepine derivatives from the reaction of alkyl azides with propargylic esters, in which, trapping vinyl gold carbenoid consecutively with alkyl azide and vinyl imine intermediate was involved.

A novel and efficient method of stereoselectively introducing α-nitromethyl group to C-7 position of 11α-hydroxyl canrenone 4 was described. In addition, this method was successfully applied in a total synthesis of Eplerenone 8. The route was characteristic of simple operation, moderate reaction conditions with 5 steps and 55% total yield, ...

An efficient and practical method has been developed for the diversity-oriented synthesis of polysubstituted 2-piperidinones via four-component reaction between substituted nitrostyrenes, aromatic aldehydes, ammonium acetate, and dialkyl malonates for the generation of a wide range of structurally interesting and pharmacologically significant compounds. It is worth mentioning that in the course ...

The pathogenesis of venous thromboembolism (VTE) is linked to inflammation and oxidant production, although specific markers for these pathways with pathological relevance to VTE have not been explored. The coagulant protein fibrinogen is post-translationally modified by nitric oxide-derived oxidants to nitrated fibrinogen in both acute and chronic inflammatory states. Therefore, ...

Domino cyclization of ketoenols and hydrazine leads to a series of polycondensed pyridazines, which reveal potential as rigid N-donor multidentate ligands for supramolecular synthesis of open coordination polymers.

New ligand for old reaction: The title reaction of aryltriflates with aliphatic olefins leads to substitution at the internal position with high selectivity. The ratio of the desired isomer (shown in the scheme) to the sum of all other isomers is generally above 10:1. The key to success is the ...

An enantioselective synthesis of (-)-(α)-kainic acid in 15 steps with an overall yield of 24% is reported. The pyrrolidine kainoid precursor with the required C2/C3 trans stereochemistry was prepared with complete diastereoselectivity via an unprecedented SmI(2)-catalyzed intramolecular [3 + 2] cycloaddition reaction of an aryl cyclopropyl ketone and an alkyne. ...

A series of fourteen (14) N-nitrophenyl-N'-(alkyl/aryl)urea and symmetrical 1,3-disubstituted urea derivatives were synthesized and evaluated for their antidepressant activity in mice. Among them, N-(4-nitrophenyl)-N'-(1'-phenylethyl)urea (1), demonstrated profound antidepressant property as reflected by significant reduction in the immobility time (89.83%), whereas compounds 2-6 showed activity values between 36 to 59% which ...

ABSTRACT: Isonicotinic acid (INA) is an important pyridine derivative used for the manufacture of isoniazid (antituberculosatic drug) and other pharmaceutically important drugs. Nitrilase catalysed processes are promising alternative for the synthesis of pharmaceutically important acids from their corresponding nitriles, over the cumbersome, hazardous, and energy demanding chemical processes. Nitrilase expression ...

Cadmium (Cd(2+) ) causes alteration of the cellular homeostasis and oxidative damage. The aim of the present study was to investigate the possible protective role of thymoquinone (TQ), a predominant bioactive component present in black seed oil (Nigella sativa) on the hepatotoxicity of Cd(2+) with special reference to its protection ...

Syntheses of thirty 2,4,6-trichlorophenylhydrazine Schiff bases 1-30 were carried out and evaluated for their in vitro DPPH radical and super oxide anion scavenging activities. Compounds 1-30 have shown a varying degree of DPPH radical scavenging activity and their IC50 values range between 4.05-369.30 µM. The compounds 17, 28, 18, 14, ...

A series of mono, bis and mixed Schiff bases (1-7) were synthesised and evaluated for potential anti-glycation and anti-oxidant activities using the bovine serum albumin - glucose assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay respectively. All compounds showed significant (p < 0.05) antiglycating activities with IC50 values (4.02 ×10-24 ± ...

BACKGROUND:: Propofol is a widely used, short-acting, and intravenously administered hypnotic agent with notable antioxidant and free radical scavenging activities. However, there are relatively few kinetic studies on the free radical scavenging ability of propofol. The goal of this study is to evaluate the kinetics of propofol scavenging 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic ...

We have developed a unique catalytic protocol for direct gem-vinylation of tryptamine derivatives employing Hg(OTf)(2) as the optimum catalyst. The intermolecular vinylations with a series of aromatic acetylenes proceeded under ambient temperature at the C2 positions of indoles with high functional group tolerance. Based on the mechanistic insights, we further ...

Two series of imidazo[2,1-b]thiazoles substituted on C-3 or C-5 with an unprotected carbohydrate moiety were synthesized. Different protective groups for position 3 of the carbohydrate moiety were tested (acetyl, tert-butyldimethylsilyl (TBDMS), and p-methoxybenzyl (PMB)) and the latter turn out to be the best strategy to obtain the desired products. Full ...

The title compound, C(19)H(17)NO(3), was synthesized using a tandem annulation reaction between 4-benzoyl-1H-pyrrole-2-carbaldehyde and (E)-ethyl 4-bromo-but-2-enoate under mild conditions. The dihedral angle between the benzene ring and the indolizine ring system is 41.73 (4)°.

A concise total synthesis of (-)-mersicarpine from a known cyclohexanone was accomplished. The azepinoindole core was constructed by a DIBAL-H-mediated reductive ring-expansion reaction of oxime.

Stereoselective total synthesis of the C(40)-diacetylenic carotenoid alloxanthin () and the C(31)-acetylenic apocarotenoid triophaxanthin () was accomplished by Wittig condensation of C(10)-dialdehyde or C(16)-keto aldehyde , respectively, with C(15)-acetylenic tri-n-butylphosphonium salt .

Reaction of methoxyvinylmethylketone with different amines and aldehydes under Lewis-acid catalysed conditions results in a novel, formal, step-wise [1+2+1+2]-cycloaddition to give dihydropyridine products.

A large set of N(5)-derivatives of cerpegin (1,1,5-trimethyl furo[3,4-c]pyridine-3,4-dione) was designed and synthesized in high yields by a simple and handy method using various primary amines for a pyridine cycle synthesis. The effects of 29 derivatives on the three types of catalytic sites of purified mammalian 20S proteasomes (CT-L, T-L ...

The asymmetric direct vinylogous Michael reaction of α,β-unsaturated γ-butyrolactams with alkylidene malonates has been developed. Various 5-substituted 3-pyrrolidin-2-ones were obtained in high yields (up to 93%) with excellent stereoselectivities (up to 94% ee, 95 : 5 dr), using a novel bifunctional C(1)-symmetric guanidine organocatalyst embodied a secondary amine subunit.

Recyclable chiral amide based organocatalyst 5 efficiently catalyzed asymmetric Strecker reaction of various aromatic and aliphatic N-benzhydrylimine with ethyl cyanoformate as cyanide source at -10 degrees C to give high yield (95%) of alpha-aminonitriles with excellent chiral induction (ee, up to 99%) with added advantage of recyclability. Based on experimental ...

Direct catalytic asymmetric aldol reaction of thioamide offers a new entry to the concise enantioselective synthesis of duloxetine. The direct aldol protocol was scalable (>20 g) to afford the aldol product in 92% ee after LiAlH4 reduction and 84% of the chiral ligand was recovered after recrystallization. The following 4 ...

ABSTRACT: BACKGROUND: Methanolic, aqueous and Total Oligomer Flavonoids (TOF)-enriched extracts obtained from the leaves of Acacia salicina 'Lindl.' were investigated for antibacterial, antimutagenic and antioxidant activities. METHODS: The antimicrobial activity was tested on the Gram positive and Gram negative reference bacterial strains. The Mutagenic and antimutagenic activities against direct acting ...

Immobilized cutinase HiC from the ascomycete Humicola insolens was applied as a novel biocatalyst for the synthesis of functionalized acryclic esters by transesterification. As a model reaction, transesterification of methyl acrylate with 6-mercapto-1-hexanol at a high molar ratio in a solvent free system was chosen. Besides two minor Michael-addition by-products, ...

This study was designed to investigate the mushroom tyrosinase inhibitory activity for the constituents isolated from Neolitsea aciculata. The stems of N. aciculata was extracted with aqueous ethanol and subjected to chromatographic separation, which led to the isolation of 11 compounds: methyl linoleate (1), catechin (2), epicatechin (3), afzelin-7-O-glucopyranoside (4), ...

Pennogenin 3-O-β-d-glucopyranosyl-(1 → 3)-[α-l-rhamnopyranosyl-(1 → 2)]-β-d-glucopyranoside, a monodesmosidic saponin isolated from Paris polyphylla Smith var. yunnanensis with promised antitumor activities, was firstly synthesized from glucoside thiol via nine steps and with 27% overall yield.

The novel pyrimidine nucleoside, (3 'S)-3 '-deoxy-3 '-fluoro-3 '-C-ethynylcytidine (1) was synthesized from cytidine in seven steps. The key step in the synthesis was the introduction of the tertiary fluorine at the 3 '-position. Compound 1 was evaluated in vitro against several RNA viruses.

The enantioselective synthesis of (S)-1-hydroxy-1,3,5-bisabolatrien-10-one 1 is here described. This sesquiterpene was prepared using (S)-3-(2-methoxy-4-methyl-phenyl)butan-1-ol as a chiral building block. Two different pathways were employed and both turned out to be high yielding, affording 1 in good chemical purity and without any racemization of the existing stereocenter. The spectroscopic data ...

CF(3) on C sp 3: Trifluoromethylation of allylsilane derivatives was accomplished through the use of CuI and Togni's reagent (1) under mild conditions. The reaction of allylsilanes without a substituent in the 2-position gave vinylsilane derivatives, while 2-substituted allylsilanes afforded desilylated products. The utility of the products was demonstrated through their further ...

The first total synthesis of the indole alkaloid nocardioazine B was accomplished in 10 steps with an overall yield of 11.8%, establishing the absolute stereochemistry of the natural product.

A novel and convenient approach to functionalized pyrroles is presented, based on Pd-catalyzed oxidative heterocyclization-alkoxycarbonylation of readily available N-Boc-1-amino-3-yn-2-ols. Reactions were carried out in alcoholic solvents at 80-100 degrees C and under 20 atm (at 25 degrees C) of a 4:1 mixture of CO-air, in the presence of the PdI2-KI ...

Stable tertiary enamides and enecarbamates undergo highly enantioselective intramolecular nucleophilic addition to aldehyde units catalyzed by chiral binol-Ti complexes under mild conditions to produce the title compounds in up to 99.5 % or greater enantiomeric excess. A positive nonlinear effect was detected and the formation of binol-Ti aggregates suggests an intricate ...

Based on the gold-catalyzed synthesis of methyleneoxazolines, a one-pot combination with an Alder-ene reaction was developed. For azodicarboxylates, good to very good yields (51-99 %) of the oxazolemethylhydrazinedicarboxylates were achieved with 3 mol % of the Gagosz catalyst, [Ph(3) PAuNTf(3) ]. In a less-selective reaction, 4-phenyl-3H-1,2,4-triazol-3,5(4 H)-dione gave lower yields (41-49 %) of the corresponding ...

ETHNOPHARMACOLOGICAL RELEVANCE: Wedelia trilobata (L.) Hitchc (Asteraceae) leaves are used in the treatment of wounds by traditional healers. Despite the use of this plant in wound healing, there is a scarcity of scientific data to support its therapeutic application. AIM OF THE STUDY: To investigate the wound healing potential of ...

An efficient, new and scalable semi-synthesis of glucan synthase inhibitors 1 and 2 from the fermentation product Enfumafungin 3 is described. The highlights of the synthesis include a high yielding ether bond formation between a bulky sulfamidate 17 and alcohol 4 and a remarkably chemoselective, improved palladium(II)-mediated Corey-Yu allylic oxidation ...

As a preliminary study, we have found that honey from manuka (<i>Leptospermum scoparium</i>) in New Zealand inhibits myeloperoxidase (MPO) activity. In this study, using a chromatographic technique, we isolated two active compounds for MPO-inhibition from manuka honey. One is methyl syringate (MSYR) and the other was identified as a novel ...

A series of (E)-1-aryloxy-1-en-3-ynes has been prepared by Sonogashira coupling of 2-bromo-3-aryloxypropenoates with terminal alkynes using Pd(PPh(3))(4) and CuI as the catalysts in Et(3)N. The resulting enynyl-aryl ethers are found to be highly applicable to the synthesis of 2,4-disubstituted furans with an ester group at C-4 position through an Au/Ag-catalyzed ...

By employing a chiral bifunctional thiourea-tertiary amine as catalyst, enantioselective Michael addition of a kojic acid derivative to nitro olefins was realised. The reactions afforded the products with good yields (up to 99%) in good enantioselectivities (up to 97% ee). In addition, the absolute configuration of one product was determined.

Purification of a MeOH extract from the aerial parts of Hylomecon vernalis Maxim. (Papaveraceae) using column chromatography furnished a new acetylated flavonol glycoside (1), together with twenty known phenolic compounds (2-21). Structural elucidation of 1 was based on 1D- and 2D-NMR spectroscopy data analysis to be quercetin 3-O-[4‴-O-acetyl-α-L-arabinopyranosyl]-(1‴→6″)-β-D-galactopyranoside (1). The ...

A new procedure for the preparation of emodin carbaldehyde and citreorosein was described, in which, ω,ω'-dibromomethylemodin triacetate was prepared as a key intermediate by NBSmediated bromination of 1,3,8-triacetylemodin. Reduction of emodin and citreorosein with SnCl(2) in a 1:1 mixture of HOAc and HCl afforded the corresponding anthrones in 90% and ...

A calcium-catalyzed direct reduction of propargylic alcohols and ethers has been accomplished by using triethylsilane as a nucleophilic hydride source. At room temperature a variety of secondary propargylic alcohols was deoxygenated to the corresponding hydrocarbons in excellent yields. Furthermore, for the first time, a catalytic deoxygenation of tertiary propargylic alcohols ...

Thawed ram spermatozoa were incubated at 37°C in the presence of dehydroascorbic acid (DHA), TEMPOL (TPL), N-acetyl-cysteine (NAC) and rutin (RUT), at 0.1 and 1 mm, in order to test their effects on sperm physiology. Cryopreserved spermatozoa from four rams were thawed, pooled, washed and incubated in TALP-Hepes with 1 mm or ...

From the 1-BuOH-soluble fraction of an MeOH extract of leaves of Antidesma japonicum, three new aliphatic glycosides, α-L: -arabinofuranosyl-(1 → 6)-β-D: -glucopyranosides of (6R,9R)-megastigma-4,7-dien-9-ol-3-one, (Z)-hex-3-en-1-ol, and methyl 2-hydroxy-2-(1'-hydroxyethyl)pentanoate 1'-O-β-D: -glucopyranoside, were isolated, along with seven known compounds.

The first enantioselective synthesis of (-)-paeonilide is reported. Starting from inexpensive furan-3-carboxylic acid the targeted monoterpene was obtained in 12 steps via an asymmetric cyclopropanation-lactonization cascade and a stereoselective side chain insertion at an acetal-like position.