Dinuclear ruthenium complexes bearing dicaboxylate and phosphine ligands. Acceptorless catalytic dehydrogenation of 1-pheylethanol

Reaction of RuH2CO(PPh3)3 with tetrafluorosuccinic acid at 100 °C gave rise to the formation of the dinuclear bis(tetrafluorosuccinate)-bridged Ru(II) complex 2, containing two water ligands. Exchange of the PPh3 in complex 2 with various diphosphine ligands afforded a series of analogous complexes 3. Reaction of the latter with 1-phenylethanol at 130 °C or with 2-propanol/Et3N at room temperature furnished the dinuclear dihydrido-bridged Ru(II) complexes 4. Complexes 2 and 4 were characterized by X-ray diffraction analysis. Both bis(tetrafluorosuccinate)-bridged complexes 3 and dihydrido-bridged complexes 4 catalyze the acceptorless dehydrogenation of 1-phenylethanol to acetophenone and dihydrogen with good yields and excellent selectivity under relatively mild conditions in the absence of acid or base. A tentative catalytic cycle for the dehydrogenation of secondary alcohols by Ru(II) complexes of type 3 is presented

Dinuclear Ruthenium Complexes Bearing Dicarboxylate and Phosphine Ligands. Acceptorless Catalytic Dehydrogenation of 1-Phenylethanol

Reaction of RuH2CO(PPh3)3 with tetrafluorosuccinic acid at 100 °C gave rise to the formation of the dinuclear bis(tetrafluorosuccinate)-bridged Ru(II) complex 2, containing two water ligands. Exchange of the PPh3 in complex 2 with various diphosphine ligands afforded a series of analogous complexes 3. Reaction of the latter with 1-phenylethanol at 130 °C or with 2-propanol/Et3N at room temperature furnished the dinuclear dihydrido-bridged Ru(II) complexes 4. Complexes 2 and 4 were characterized by X-ray diffraction analysis. Both bis(tetrafluorosuccinate)-bridged complexes 3 and dihydrido-bridged complexes 4 catalyze the acceptorless dehydrogenation of 1-phenylethanol to acetophenone and dihydrogen with good yields and excellent selectivity under relatively mild conditions in the absence of acid or base. A tentative catalytic cycle for the dehydrogenation of secondary alcohols by Ru(II) complexes of type 3 is presented

Early versus late surgical drainage for obstructive pancreatitis in an experimental model

BACKGROUND: Chronic pancreatitis (CP) is characterized by intractable abdominal pain, and pancreatic exocrine and endocrine dysfunction. This study investigated whether early surgical drainage of pancreatic duct obstruction leads to improved recovery of pancreatic function compared with late surgical drainage in an experimental model of chronic obstructive pancreatitis. METHODS: Twenty-one piglets underwent pancreatic duct ligation and subsequent longitudinal pancreaticojejunostomy after 3 weeks (early drainage) or 6 weeks (late drainage), and drainage continued for 6 weeks. In controls with CP pancreatic duct ligation was continued for 12 weeks without a drainage procedure. RESULTS: Histological pancreatitis scores decreased with early drainage (P = 0.005), but not with late drainage. Pancreatic secretion of amylase and lipase was restored after early but not late drainage (P = 0.003 and P = 0.048 respectively). Excretion levels of lipase were restored to near-baseline preligation levels after early drainage. Pancreatic endocrine function (glucose tolerance test) showed no insufficiency in either group. CONCLUSION: In this model of early versus late surgical drainage of obstructive pancreatitis, histology grades and pancreatic exocrine function showed improvement in the early drainage group but no recovery in the late drainage grou

Dynamic Kinetic Resolution for the Synthesis of Esters, Amides and Acids Using Lipases

10.1002/9780470748589.ch4Practical Methods for Biocatalysis and Biotransformations133-16