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A water-soluble and air-stable Pd(NH3)2Cl2/cationic 2,2'-bipyridyl system was found to be a highly-efficient and reusable catalyst for the coupling of aryl iodides and alkenes in neat water using Bu(3)N as a base. The reaction was conducted at 140 degrees C in a sealed tube in air with a catalyst loading as low as 0.0001 mol % for the coupling of activated(More)
Three new clerodane-type diterpenes, 6alpha,16-dihydroxycleroda-3,13-dien-15-oic acid (1), 6alpha,16-dihydroxycleroda-4(18),13-dien-15-oic acid (2), and 4alpha,18beta-epoxy-16-hydroxyclerod-13-en-15-oic acid (3), and four new protoberberine alkaloids, (-)-8-oxo-10-hydroxy-2,3,9-trimethoxyberberine (4), (-)-8-oxo-2,11-dihydroxy-3,10-dimethoxyberberine (5),(More)
Novel π-extended conjugated amphiphiles composed of a hydrophilic section of two quaternary ammonium groups and p-phenylene ethynylene with adjustable alkyl chain hydrophobic section were prepared by a multistep synthesis. These dicationic amphiphiles showed good water solubility and formed a tubular assembly in water. The evidence for the nanotubular comes(More)
A heterogeneous catalyst, nanosized MCM-41-Pd, was used to catalyze the Sonogashira coupling of aryl and heteroaryl halides with terminal alkynes in the presence of CuI and triphenylphosphine. The coupling products were obtained in high yields using low Pd loadings to 0.01 mol%, and the nanosized MCM-41-Pd catalyst was recovered by centrifugation of the(More)
Selective preparation of pyridine derivatives from two different alkynes and a nitrile was achieved by a novel procedure in which an alkyne and a nitrile couple first to give an azazirconacyclopentadiene followed by reaction with the second alkyne in the presence of 1 equiv of NiCl(2)(PPh(3))(2). This procedure gives only single products of pyridine(More)
A water-soluble PdCl₂(NH₃)₂/cationic 2,2'-bipyridyl system was found to be a highly efficient catalyst for Stille coupling of aryl iodides and bromides with organostannanes. The coupling reaction was conducted at 110 °C in water, under aerobic conditions, in the presence of NaHCO₃ as a base to afford corresponding Stille coupling products in good to high(More)
The catalytic method features a cooperative interaction between Ni and Al imparting remote C-H alkenylation at the C5 position of imidazo[1,5-a]pyridine with alkynes at mild conditions. Exclusion of AlMe3 switches the selectivity to the C3 position. Reactions with styrene and other olefinic substrates affording C5-adducts by Ni/Al catalysis are also(More)
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