Aerobic oxidation under visible light irradiation of a fluorescent lamp with a combination of carbon tetrabromide and triphenyl phosphine

A combination of CBr₄–Ph₃P, a non-metal method, enables us to carry out aerobic photo-oxidation of alcohols and aromatic methyl groups to the corresponding carboxylic acids under irradiation of vis from a general-purpose fluorescent lamp. Aliphatic primary- and secondary alcohols, benzyl alcohols, and methyl groups at the aromatic nucleus generally afforded the carboxylic acids directly in good to high yield.     

Synthesis of Stable Atropisomers of Dialkyl-4-Ethoxy-1-(8-((2-ethoxy-2-oxoacetyl)-amino)-1-naphthyl)-5-oxo-4,5-dihydro-1H-pyrrole-2,3-dicarboxylates

Summary.  Protonation of the reactive 1:1-intermediate produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates with diethyl N,N′-(naphthalene-1,8-diyl)-dioxamate leads to a vinylphosphonium salt which undergoes an intramolecular Wittig reaction to produce dialkyl-4-ethoxy-1-(8-((2-ethoxy-2-oxoacetyl)-amino)-1-naphthyl)-5-oxo-4,5-dihydro-1H-pyrrole-2,3-dicarboxylates in good yields. The title compounds exist as stable rotamers as a result of restricted rotation around the single bond linking the naphthalene moiety and the heterocyclic system. The calculated free energy of activation for interconversion of the atropisomers amounts to about 102±2 kJ · mol⁻¹. Corresponding author. E-mail: isayavar@yahoo.com Received February 5, 2002. Accepted March 19, 2002     

High-performance liquid chromatography of the coordination isomers of triphenylphosphine-substituted homo- and hetero-bimetallic carbonyl complexes of manganese and rhenium

The isocratic normal-phase high-performance liquid chromatography of a series of triphenylphosphine (PPh₃)-substituted homo- and hetero-dinuclear metal carbonyl complexes [MM′ (CO)_10−n(PPh₃)_n, where M,M′ = Mn, Re; N = 1,2] is reported. A column packed with silica bonded with phenyl groups was used after preliminary experiments showed that columns packed with conventional silica, and with silica bonded with amion-cyano groups were unsatisfactory for separation. The mobile phases used were hexane-toluene (8:2) and hexane-dichloromethane (90:10). The results suggest that besides the symmetry-imposed polarity of the complexes, the nature of the metal and substituent ligand also determine their retention characteristics.     

Triphenylphosphine-catalyzed isomerization of alkynyl ketones in aqueous solution

An efficient isomerization of alkynyl ketones to(E,E)-diene ketones was developed.The reaction catalyzed by 20 mol% triphenylphosphine in aqueous media gave the desired products in good yields.     

Synthesis,Spectral, Valence‐Bond Parameters,and Single Crystal X‐ray Structural Studies on [Ni(dnpdtc)(PPh3)(NCS)] and [Ni(dnpdtc)(PPh3)(CN)]

Two new nickel complexes withplanar surrounding of Ni [Ni(dnpdtc)(PPh₃)(NCS)] (1) and [Ni(dnpdtc)(PPh₃)(CN)] (2) (dnpdtc=N, N‐dipropyldithiocarbamate) were prepared from the parent dithiocarbamate and were characterized by elemental analysis, electronic, IR and NMR spectra. The structures of both the complexes were determined by single crystal X‐ray crystallography. Thioureide stretching vibrations occur at 1528 cm^‐1 and 1521 cm^‐1 for 1 and 2 respectively. Large ³¹P chemical shifts were observed for the two compounds. A significant asymmetry in Ni—S bond distances was observed in compound 1 [2.1700(16) and 2.2251(17)Å] whereas in compound 2 the bond distances were almost similar [2.2100(14) and 2.2122(13)Å]. A marginal difference was observed with respect to the thioureide bond distances [1.340(6)Å for 1 and 1.312(5)Å for 2 ]. The observation clearly supports the less effective trans influence of SCN^— over PPh₃. However, PPh₃ and CN^— show almost similar trans influence.     

Preparation of thiocyanates and isothiocyanates from alcohols, thiols, trimethylsilyl-, and tetrahydropyranyl ethers using triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone (DDQ)/n-Bu4NSCN system

A combination of triphenylphosphine (PPh₃) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) provides a safe and easily available mixed reagent system for the conversion of 1° and 2° alcohols, thiols, trimethylsilyl-, and tetrahydropyranyl ethers to their corresponding thiocyanates and the 3° ones to isothiocyanates in good to high yields.     

A synthesis of isoxazoles through the reaction of activated acetylenes and alkyl 2-nitroethanoates in the presence of triphenylphosphine

The reaction of dialkyl acetylenedicarboxylates or dibenzoylacetylene with alkyl 2-nitroethanoates in the presence of triphenylphosphine leads to functionalized isoxazoles in good yields.     

Reaction of N-Heterocycles with Acetylenedicarboxylates in the Presence of N-Alkylisatins or Ninhydrin. Efficient Synthesis of Spiro Compounds

Summary. The 1,3-dipolar intermediates generated by addition of isoquinoline, to dialkyl acetylenedicaboxylates are trapped by N-alkylisatins to produce dialkyl 1,2-dihydro-2-oxo-1-alkylspiro[3H-indol-3,2′-[2H,11bH][1,3]oxazino[2,3-a]isoquinoline]-3′,4′-dicarboxylates in excellent yields. The reaction of isoquinoline, quinoline, or pyridine with dimethyl acetylenedicarboxylate in the presence of ninhydrin led to dimethyl 1,2-dihydro-1,3-dioxospiro[3H-indene-3,2′-[2H,11bH][1,3]oxazino[2,3-a]isoquinoline]-3′,4′-dicarboxylate, dimethyl 1,2-dihydro-1,3-dioxospiro[3H-indene-3,3′[3H,4aH][1,3]oxazino[3,2-a]quinoline]-1,2-dicarboxylate, or dimethyl 1,2-dihydro-1,3-dioxospiro[3H-indene-3,2′-[2H,9aH]pyrido[2,1-b][1,3]oxazino]-3,4-dicarboxylate.     

31P CP-MAS NMR,Vibrational, and X-Ray Characterization of the Adducts of Triphenylphosphine Sulfide with ICl and IBr

The reactions between triphenylphosphine sulfide (Ph₃PS) and ICl in CCl₄ and IBr in CH₂Cl₂ in 1 : 1 molar ratio give the solid adducts Ph₃PS · ICl ( I ) and Ph₃PS · IBr ( II ) whose structures have been solved by X-ray diffraction. Compounds I and II consist of discrete molecule units and feature the S–I–Cl or S–I–Br linear group. The S–I bond distances in I , II (2.641(1), 2.665(1) Å respectively) and in compound 2 Ph₃PS · 3 I₂ ( III ) (2.729(2) Å) are correlable to the net increase in the I–X (X = Cl, Br, I) bond distance. The structural features of I , II and III are in accordance with ³¹P CP–MAS NMR, FT-Raman and FT-IR spectral data, and elucidate the nature of the donor (Ph₃PS)-acceptor (ICl, IBr, I₂) interaction.     

正丁基黄原酸铜与三苯基膦配合物的结构和表征

合成并通过IR、UV、~1HNMR、TGA及单晶X射线衍射研究了正丁基黄原酸铜与三苯基膦配合物的结构和性能。该配合物属单斜晶系,空间群P2_1/c,晶胞参数为:a=11·000(2),b=20·090(4),c=17·320(4),β=103·800(3)°,V=3717·1(13)~3,Z=4。中心铜原子与来自正丁基黄原酸根的两个硫原子及三苯基膦的两个磷原子配位,呈扭曲的四面体构型。IR,UV及~1HNMR分析结果与晶体结构一致。热重分析研究表明该配合物从110℃开始分解,到295℃分解完全,留下CuS。