An assessment of the technique of simultaneous cooling in conjunction with microwave heating for organic synthesis

In the light of the controversy in the area and since reports using simultaneous cooling in conjunction with microwave heating are appearing in the literature, we were keen to assess the methodology, looking at temperature measurement issues as well as the use of the technique in three classes of reaction, namely a Heck coupling, a Diels-Alder cycloaddition and a Michael addition. We present our initial findings here.     

The luminescence spectrum of the uranyl ion contains no evidence of strong vibronic anharmonicity in the first electronic excited state

The work of Liu and Vikhnin [Chem. Phys. Lett. 437 (2007) 56] on anharmonic charge-transfer vibronic states in uranyl compounds is examined critically. It is concluded that there is currently no experimental evidence to justify the use of a phenomenological model of anharmonic vibronic coupling in these systems.     

Solvent‐free synthesis of α‐aminonitriles from aldehydes,amines and trimethylsilyl cyanide catalyzed by thallium(III) chloride tetrahydrate

A straightforward and efficient method has been developed for the synthesis of α‐aminonitriles by combining aldehydes, amines and trimethylsilyl cyanide in the presence of a catalytic amount of thallium(III) chloride tetrahydrate (1 mol%) under solvent‐free conditions at room temperature. Copyright © 2008 John Wiley & Sons, Ltd.     

Copper(I) Oxide Catalyzed Formation of C?S Bond Mediated by N,N′‐Type Ligand

1,10‐Phenanthroline, a simple and cheap N,N′‐type ligand, was found to work well as the ligand of C? S coupling catalyzed by Cu₂O. The corresponding coupling products were synthesized in good to excellent yields (75%–99%) in DMSO at 80°C. A variety of aryl halides and thiols were investigated and satisfactory results were obtained.     

Palladium‐catalysed P?C bond forming reactions between diphenylphosphine and ortho‐substituted aryl bromides

The use of palladium catalysts derived from 1,1′‐bis‐diisopropylphosphino‐ferrocene and a microwave heating source allows the coupling of a range of ortho‐substituted aryl bromides to diphenylphosphine derivatives to proceed in good yield in under 30 min. Optimization studies reveal that the combination of diphenylphosphine and DABCO is superior to more basic phosphide nucleophiles such as Ph₂PK or Ph₂PMgBr. High yields are only observed when moderately bulky electron rich diphosphines are used as ligands. The differences between P? C coupling and other cross‐coupling reactions are discussed in the light of the reactivity observed. Studies aimed at producing industrially important 1,2‐bis‐phosphino‐benzene ligands are also described. Copyright © 2009 John Wiley & Sons, Ltd.     

Spin-rotation coupling and Fermi–Walker transport

It is demonstrated that a spin-rotation coupling term only appears in the Hamiltonian of a Dirac particle if the rotating frame obeys the rules of Fermi–Walker transport. This is illustrated by examples in Minkowski space and the paper concludes with some speculations about spin-rotation coupling in Kerr space-time.     

Efficient synthesis of 2,3-dihydro-1,4-benzoxazines via intramolecular copper-catalyzed O-arylation

A highly efficient synthetic approach to 2,3-dihydro-1,4-benzoxazines is described. The method involves a mild intramolecular copper-catalyzed O-arylation of β aminoalcohol, which works well without N-protection.     

Studies on the Preparation of Bioactive Oligomerstilbene by Oxidative Coupling Reaction (I) -Preparation of Shegansu B using Silver Oxide as Oxidant

The oxidative coupling reaction of isorhapontigenin using sliver oxide as oxidant afforded a major product, named shegansu B (2), which was isolated from the roots of Belamcanda chinensis (L.) DC. Both the natural and synthetic Shegansu B have the same potent antagonism activities of leukotriene B4, D4 receptor .     

光色效应(Fe,Mn)\:LiNbO3晶体非挥发性全息存储中自衍射效应的实验研究

在双掺杂 (Fe ,Mn)…LiNbO3 晶体光色效应非挥发性全息存储实验中 ,观测到光束耦合作用导致的自增强和自衰减效应。根据这种自衍射效应 ,归纳了四种记录和光固定实验组合方案。实验结果表明 ,在记录和光固定过程中利用自增强效应得到的最高衍射效率为利用自衰减效应得到的衍射效率的两倍左右 ,说明在实际应用中必须考虑和利用自增强效应。