Copper salt-catalyzed homo-coupling reaction of potassium alkynyltrifluoroborates: a simple and efficient synthesis of symmetrical 1,3-diynes

The copper-catalyzed dimerization of alkynyltrifluoroborates proceeds readily with good yields. The homo-coupling reaction can be effected in DMSO, in the open air, using Cu(OAc)(2) as catalyst in the absence of any other additives. A variety of functional groups are tolerated. (C) 2008 Elsevier Ltd. All rights reserved.

Synthesis of unnatural cyclitols via a combined enzymatic-palladium catalysis approach

The Suzuki-Miyaura cross-coupling reaction of a hydroxylated vinyl bromide obtained by a chemoenzymatic approach with a diverse range of potassium organotrifluoroborates has been accomplished catalyzed by Pd(PPh(3))(4) in satisfactory yields. A variety of functional groups are tolerated in the nucleophilic partner. (C) 2008 Elsevier B.V. All rights reserved.

Stereoselective synthesis of the dolastatin units by organotrifluoroborates additions to alpha-amino aldehydes

Dolastatin units were synthesized from the 1,2-addition reactions of potassium allyl or crotyltrifluoroborate salts to aldehyde derivatives from natural amino acids. The reactions were carried out in presence of a phase-transfer catalyst in a biphasic medium at room temperature and excellent yields (>89-93%) and stereoselective (>90:10 to 98:2) were obtained. The dolastatin units 8 and 14a-b were obtained after three steps in good overall yields (50-62%). (C) 2007 Elsevier Ltd. All rights reserved.

Influence of ammonium sulphate feeding time on fed-batch Arthrospira (Spirulina) platensis cultivation and biomass composition with and without pH control

Previous work demonstrated that a mixture of NH(4)Cl and KNO(3) as nitrogen source was beneficial to fed-batch Arthrospira (Spirulina) platensis cultivation, in terms of either lower costs or higher cell concentration. On the basis of those results, this study focused on the use of a cheaper nitrogen source mixture, namely (NH(4))(2)SO(4) plus NaNO(3), varying the ammonium feeding time (T = 7-15 days), either controlling the pH by CO(2) addition or not. A. platensis was cultivated in mini-tanks at 30 degrees C, 156 mu mol photons m(-2) s(-1), and starting cell concentration of 400 mg L(-1), on a modified Schlosser medium. T = 13 days under pH control were selected as optimum conditions, ensuring the best results in terms of biomass production (maximum cell concentration of 2911 mg L(-1), cell productivity of 179 mg L(-1) d(-1) and specific growth rate of 0.77 d(-1)) and satisfactory protein and lipid contents (around 30% each). (C) 2011 Elsevier Ltd. All rights reserved.

Sterilization of Medical Devices by Ethylene Oxide, Determination of the Dissipation of Residues, and Use of Green Fluorescent Protein as an Indicator of Process Control

Ethylene oxide (EO) is used to sterilize Oxygenator and Tubing applied to heart surgery. Residual levels of EO and its derivatives, ethylene chlorohydrin (ECH) and ethylene glycol (EG), may be hazardous to the patients. Therefore, it must be removed by the aeration process. This study aimed to estimate the minimum aeration time for these devices to attain safe limits for use (avoiding excessive aeration time) and to evaluate the Green Fluorescent Protein (GFP) as a biosensor capable of best indicating the distribution and penetration of EO gas throughout the sterilization chamber. Sterilization cycles of 2, 4, and 8 h were monitored by Bacillus atrophaeus ATCC 9372 as a biological indicator (131) and by the GFP. Residual levels of EO, ECH, and EG were determined by gas chromatography (GC), and the residual dissipation was studied. Safe limits were reached right after the sterilization process for Oxygenator and after 204 h of aeration for Tubing. In the 2 h cycle, the GFP concentration decreased from 4.8 (+/- 3.2)% to 7.5 (+/- 2.5)%. For the 4 h cycle, the GFP concentration decreased from 17.4 (+/- 3.0)% to 21.5 (+/- 6.8)%, and in the 8 h cycle, it decreased from 22.5 (+/- 3.2)% to 23.9 (+/- 3.9)%. This finding showed the potentiality for GFP applications as an EO biosensor. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 9113: 626-630, 2009

Novel benzofuroxan derivatives against multidrug-resistant Staphylococcus aureus strains: Design using Topliss` decision tree, synthesis and biological assay

The aim of this study was the design of a set of benzofuroxan derivatives as antimicrobial agents exploring the physicochemical properties of the related substituents. Topliss` decision tree approach was applied to select the substituent groups. Hierarchical cluster analysis was also performed to emphasize natural clusters and patterns. The compounds were obtained using two synthetic approaches for reducing the synthetic steps as well as improving the yield. The minimal inhibitory concentration method was employed to evaluate the activity against multidrug-resistant Staphylococcus aureus strains. The most active compound was 4-nitro-3-(trifluoromethyl)[N`-(benzofuroxan-5-yl) methylene] benzhydrazide (MIC range 12.7-11.4 mu g/mL), pointing out that the antimicrobial activity was indeed influenced by the hydrophobic and electron-withdrawing property of the substituent groups 3-CF(3) and 4-NO(2), respectively. (C) 2011 Elsevier Ltd. All rights reserved.

One-pot synthesis of alpha,beta-epoxy ketones by palladium-catalyzed epoxidation-oxidation of terminal allylic alcohols

Described herein is a one-pot synthesis of a,p-epoxy ketones using a palladium-catalyzed epoxidation-oxidation sequence. Functionalized terminal allylic alcohols are treated with m-CPBA Under mild reaction conditions to obtain the alpha,beta-epoxy ketones. The main benefit of this approach is that the epoxidation of the terminal double bond and the oxidation of the secondary alcohol occured in the same reaction under mild reactions and both electron-donating and electron-withdrawing functionalities are tolerated in the reaction sequence. (C) 2010 Elsevier Ltd. All rights reserved.

Efficient sonochemical synthesis of novel 3,5-diaryl-4,5-dihydro-1H-pyrazole-1-carboximidamides

An Ultrasound-assisted preparation of a series of novel 3,5-diaryl-4,5-dihydro-1H-pyrazole-1-carboximidamides that proceeds via the efficient reaction of chalcones with aminoguanidine hydrochloride under clean conditions is described. (C) 2009 Elsevier B.V. All rights reserved.

Design, synthesis, antimicrobial activity and molecular modeling studies of novel benzofuroxan derivatives against Staphylococcus aureus

Molecular modi. cation is a quite promising strategy in the design and development of drug analogs with better bioavailability, higher intrinsic activity and less toxicity. In the search of new leads with potential antimicrobial activity, a new series of 14 4-substituted [N`-(benzofuroxan-5-yl) methylene] benzohydrazides, nifuroxazide derivatives, were synthesized and tested against standard and multidrug-resistant Staphylococcus aureus strains. The selection of the substituent groups was based on physicochemical properties, such as hydrophobicity and electronic effect. These properties were also evaluated through the lipophilic and electrostatic potential maps, respectively, considering the compounds with better biological pro. le. Twelve compounds exhibited similar bacteriostatic activity against standard and multidrug-resistant strains. The most active compound was the 4-CF(3) substituted derivative, which presented a minimum inhibitory concentration (MIC) value of 14.6-13.1 mu g/mL, and a ClogP value of 1.87. The results highlight the benzofuroxan derivatives as potential leads for designing new future antimicrobial drug candidates. (C) 2009 Elsevier Ltd. All rights reserved.

Synthesis of potassium and tetra n-butylammonium 2-substituted-1,3-dithianotrifluoroborate salts and addition to chiral cyclic N-acyliminium ions

The synthesis of potassium 2-substituted-1,3-dithianotrifluoroborate salts and tetra-n-butyl ammonium derivatives is described. The reaction proceeds under mild reaction conditions and the corresponding products were obtained in moderate to good yields. The reactivity of these compounds in rections with chiral cyclic N-acyliminium ions was evaluated.

Ultrasound-assisted synthesis of functionalized 1,3-enynes by palladium-catalyzed cross-coupling reaction of alpha-styrylbutyltelluride with alkynyltrifluoroborate salts

An ultrasound-assisted synthesis of functionalized 1,3-enyne scaffolds is described and illustrated by palladium-catalyzed cross-coupling of potassium alkynyltrifluoroborate salts and alpha-styrylbutyltellurides. This procedure offers easy access to 1,3-enyne architecture that contains aliphatic and aromatic groups in good to excellent yields.

Synthesis of 2-Aryl- and 2,5-Diarylfurans and Thiophenes by Suzuki-Miyaura Reactions Using Potassium Trifluoroborate Salts and Heteroaryltellurides

The Suzuki-Miyaura cross-coupling reaction of 2-(butyltellanyl) or 2,5-bis-(butyltellanyl)furans and thiophenes with potassium aryltrifluoroborate salts catalyzed by palladium afforded 2-aryl- or 2,5-diaryl-furans and thiophenes in moderate to good yields.

Synthesis and characterization of the [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru(bpy)(2)Cl](PF(6))(2) dimer

The polymetallic [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru( bpy)(2)Cl](PF(6))(2) complex (bpy = 2,2`-bipyridine, BPE = trans- 1,2-bis(4-pyridil) ethylene and py = pyridine) was assembled by the combination of an electroactive [Ru(3)O] moiety with a [ Ru( bpy) 2( BPE) Cl] photoactive centre, and its structure was determined using positive ion electrospray (ESI-MS) and tandem mass (ESI-MS/MS) spectrometry. The [Ru(3)O(CH(3)COO)(6)(py)(2)(BPE)Ru(bpy)(2)Cl] (2+) doubly charged ion of m/z 732 was mass-selected and subject to 15 eV collision-induced dissociation, leading to a specific dissociation pattern, diagnostic of the complex structure. The electronic spectra display broad bands at 409, 491 and 692 nm ascribed to the [Ru(bpy)(2)(BPE)] charge-transfer bands and to the [Ru(3)O] internal cluster transitions. The cyclic voltammetry shows five reversible waves at - 1.07 V, 0.13 V, 1.17 V, 2.91 V and - 1.29 V (vs SHE) assigned to the [Ru(3)O](-1/0/+ 1/+ 2/+3) and to the bpy (0/-1) redox processes; also a wave is observed at 0.96 V, assigned to the Ru (+2/+ 3) pair. Despite the conjugated BPE bridge, the electrochemical and spectroelectrochemical results indicate only a weak coupling through the pi-system, and preliminary photophysical essays showed the compound decomposes under visible light irradiation.

Genetic analysis of complement C1s deficiency associated with systemic lupus erythernatosus highlights alternative splicing of normal C1s gene

Deficiencies of complement proteins of the classical pathway are strongly associated with the development of autoimmune diseases. Deficiency of Clr has been observed to occur concomitantly with deficiency in Cls and 9 out of 15 reported cases presented systemic lupus erythernatosus (SLE). Here, we describe a family in which all four children are deficient in Cls but only two of them developed SLE. Hemolytic activity mediated by the alternative and the lectin pathways were normal, but classical pathway activation was absent in all children`s sera. Cls was undetectable, while in the parents` sera it was lower than in the normal controls. The levels of Clr observed in the siblings and parents sera were lower than in the control, while the concentrations of other complement proteins (C3, C4, MBL and MASP-2) were normal in all family members. Impairment of Cls synthesis was observed in the patients` fibroblasts when analyzed by confocal microscopy. We show that all four siblings are homozygous for a mutation at position 938 in exon 6 of the Cls cDNA that creates a premature stop codon. Our investigations led us to reveal the presence of previously uncharacterized splice variants of Cls mRNA transcripts in normal human cells. These variants are derived from the skipping of exon 3 and from the use of an alternative 3` splice site within intron I which increases the size of exon 2 by 87 nucleotides. (c) 2007 Elsevier Ltd. All rights reserved.