Acceptorless photocatalytic dehydrogenation for alcohol decarbonylation and imine synthesis

It has come to light: Renewed interest in conversions of highly oxygenated materials has motivated studies of the organometallic-catalyzed photocatalytic dehydrogenative decarbonylation of primary alcohols into alkanes, CO, and H(2) . Methanol, ethanol, benzyl alcohol, and cyclohexanemethanol are readily decarbonylated. The photocatalysts are also active for amine dehydrogenation to give N-alkyl aldimines and H(2) .     

Enantioselective addition of secondary phosphines to methacrylonitrile: catalysis and mechanism

A highly enantioselective intermolecular hydrophosphination reaction is described. The (Pigiphos)nickel(II)-catalyzed reaction of secondary phosphines and methacrylonitrile gives chiral 2-cyanopropylphosphines in good yield and high enantiomeric excess (ee's up to 94%; (R)-(S)-Pigiphos = bis[(R)-1-[(S)-2-(diphenylphosphino)ferrocenyl]ethyl}cyclohexylphos phine). We propose a mechanism involving coordination of methacrylonitrile to the dicationic nickel catalyst followed by 1,4-addition of the phosphine, and then, rate-determining proton transfer. This mechanism is supported by (a) the experimentally determined rate law (rate = k'[Ni][methacrylonitrile][t-Bu(2)PH]), (b) a large primary deuterium isotope effect k(H)/k(D) = 4.6(1) for the addition of t-Bu(2)PH(D) at 28.3 degrees C in toluene-d(8), (c) the isolation and characterization of the species [Ni(kappa(3)-Pigiphos)(kappaN-methacrylonitrile)](2+), and (d) DFT calculations of model compounds.     

Tris(oxazolinyl)boratomagnesium-catalyzed cross-dehydrocoupling of organosilanes with amines, hydrazine, and ammonia

We report magnesium-catalyzed cross-dehydrocoupling of Si-H and N-H bonds to give Si-N bonds and H(2). A number of silazanes are accessible using this method, as well as silylamines from NH(3) and silylhydrazines from N(2)H(4). Kinetic studies of the overall catalytic cycle and a stoichiometric Si-N bond-forming reaction suggest nucleophilic attack by a magnesium amide as the turnover-limiting step.     

YOYO as a Dye to Track Penetration of LK15 DNA Complexes in Spheroids: Use and Limits

To elucidate the reasons underlying the poor penetration of non-viral vectors in tissues, relating transport properties to physico-chemical parameters of vectors may be crucial. These properties can be influenced by the presence of multiples labels that are used. Therefore utilizing a vector with minimum of labels preferably not more than one is important to studying penetration in tissues. The cell impermeant bisintercalating dye YOYO-1 was found suitable to both monitor the formation of complexes between DNA and an amphipathic peptide LK15 and, to track their penetration in HCT116 spheroids by confocal microscopy. The results revealed a limited decrease of fluorescence ascribed to the high affinity of YOYO-1 to bind DNA. The residual fluorescence of complexes can be exploited to monitor penetration into spheroids, after correction for YOYO-1 attenuation, and to revealing hyaluronidase-induced reduced binding. Hence high affinity dyes such as YOYO-1 with inefficiently quenched fluorescence may be important to establish a relation between novel medicines characteristics and penetration in tissues.     

Neuropeptide delivery to the brain: a von Willebrand factor signal peptide to direct neuropeptide secretion

Background  

Multiple neuropeptides, sometimes with opposing functions, can be produced from one precursor gene. To study the roles of the different neuropeptides encoded by one large precursor we developed a method to overexpress minigenes and establish local secretion.