α-Phenylselanyl imines: preparation of β-phenylselanyl amines and original synthesis of allylaziridines

Resorting to suitable methods, a wide variety of α-phenylselanyl imines 2-5 were prepared from α-phenylselanyl aldehydes and α-phenylselanyl ketones 1. These compounds were reduced to afford β-phenylselanyl amines 6-9. Our experimental conditions have limited the well known deselenenylation side-reaction occurring with most hydrides. On the other hand, the reaction of α-phenylselanyl imines 2 with organometallics led to the expected addition products only in the case of allylated derivatives. Depending on the temperature, either β-phenylselanyl amines 11 or unexpected allylaziridines 12 were recovered.     

Unexpected Formation of a π‐Coordinate Schiff Base Cobalt(0) Complex

Both tetrakis(trimethylphosphine)cobalt(0) and methyltetrakis(trimethylphosphine)cobalt(I) react with 2‐(benzylideneamino)pyridine ( 1 ) exclusively giving a complex of composition (η²(N,C)‐2‐Py‐N=CH‐C₆H₅)Co(PMe₃)₃ ( 2 ), which is shown by single‐crystal X‐ray diffraction to constitute the first π‐coordinate imine cobalt(0) complex. The route of formation is proposed and discussed.     

一种新型液相色谱屏蔽键合相的色谱性能

烷基硅胶键合固定相 ,特别是十八烷基键合固定相 ,是应用最广泛的反相色谱固定相 ,改变流动相组成 ,就可实现大多数有机化合物的分离分析 .但是 ,由于硅胶表面残留硅醇基的存在 ,分离某些极性化合物 ,特别是碱性有机化合物时使色谱峰变形拖尾 ,灵敏度下降 .采用封端技术也不能完全消除残留硅醇基的影响 .在分离碱性物质时大都采用缓冲溶液流动相 ,长期使用缓冲溶液将影响仪器和色谱柱的性能和寿命 .近年来 ,为了改善碱性化合物的分离 ,提出了空间保护相 [1] 和烷基酰胺屏蔽相 [2 ,3] .依据静电屏蔽原理 ,我们 [4 ]曾制备了十四烷基胺反相色…     

Practical synthesis of 3-bromo-5,6-dihydropyridin-2-ones via β,γ-unsaturated α-bromo-ketene/imine cycloaddition

An approach to 3-bromo-4-alkyl-6-aryl-5,6-dihydropyridin-2-ones and 3-bromo-5-ethyl-6-aryl-5,6-dihydropyridin-2-ones starting from β,γ-unsaturated α-bromoketenes and imines is reported. The presence of a bromine atom on the double bond allows performing aziridination or bromine displacement with an amine. The reaction gave fused bicyclic N-allyl-aziridines or 3-amino-substituted 5,6-dihydropyridin-2-ones, depending on the substituents on the six-membered ring.     

Azetidines as ligands in the Pd(II) complexes series

The preparation of palladium (II) complexes having sterically congested azetidines as ligands is described. Diastereomerically pure α-alkylamino and α-alkylimino azetidines react with Na₂PdCl₄ to afford the corresponding bidendate Pd(II) complexes, whereas 2-cyano azetidines can be used to access bidendate Pd(II) complexes containing an amino-imidate moiety. Preliminary study of the catalytic activity of these new complexes in the Suzuki cross-coupling reaction is presented.     

An unexpected base-induced rearrangement of tritylamine

An unexpected rearrangement was observed during the treatment of tritylamine with n-butyllithium, leading to the formation of an imine.     

Synthesis, crystal structure and imine bond activation of a copper(II) Schiff base complex

A new copper(II) complex [Cu(HL)(ClO₄)](ClO₄) (1), where HL is a multidentate Schiff base N,N′-(2-hydroxypropane-1,3-diyl)bis(pyridine-2-aldimine), is prepared, structurally characterized by X-ray crystallography and its spectral and electrochemical properties studied. The complex forms a one-dimensional chain in the solid state structure in which the monomeric Cu(HL) units are linked by the perchlorate ligand. The complex has an axially elongated six coordinate geometry (4+2) with a CuN₄O₂ core in which the Schiff base ligand displays a tetradentate mode of bonding in the basal plane. The axial ligand is perchlorate with a significantly long Cu–O bond of ca. 2.6 Å. The one-electron paramagnetic complex displays a cyclic voltammetric response for the Cu(II)/Cu(I) couple at 0.01 V versus SCE in MeCN–0.1 M TBAP. The azomethine bond of the Schiff base in 1 on treatment with H₂O₂ undergoes oxidative conversion to form a bis(picolinato)copper(II) · dihydrate species through the formation of an amido intermediate as evidenced from the solution infrared spectral studies.     

Cyclometallated platinum complexes with heterocyclic ligands

The reactions of [Pt₂Me₄(μ-SMe₂)₂] with imine ligands derived from 3-furaldehyde, 3- or 4-pyridinealdehyde and N,N-dimethylethylenediamine, and 3-furaldehyde and chlorobenzylamine are reported. The furane ligands coordinated to platinum through the nitrogen donor and could be forced to orthometallate under severe conditions. The ligands with pyridine rings gave only substitution of the ligand for the dimethylsulphide. The oxidative addition reactions of the orthometallated complexes with methyl iodide as well as the complexes' reactions with triphenylphosphine are also reported. Correlation between aromaticity of the orthometallated ring and reactivity of the complexes is observed.     

Examples of interesting non-metal compounds derived from elemental fluorine

Elemental fluorine is essential for the preparation of many fluorine-containing compounds. A few examples from the author's past research are presented to illustrate this in tribute to the Centenary of the awarding of the Nobel Prize to Henri Moissan.