Regioselective Synthesis of 3- and 5-Functional Derivatives of Pyrazolidine. 1. Synthesis of Ketones of the Pyrazolidine Series

When 5-hydroxypyrazolidines reacted with ketones on the surface of basic adsorbents the 3-regioisomers were obtained in addition to the expected 5-oxoalkylpyrazolidines. The conditions for the regiodirection of the process have been found. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, 1566–1572, October, 2005.     

Pyrazolidine derivatives with heteroaryl urea as dipeptidyl peptidase IV inhibitors

In the continuation of efforts to modify the structure of our novel DP-IV inhibitors, a series of pyrazolidine derivatives with heteroaryl urea was synthesized and evaluated for their ability to inhibit dipeptidyl peptidase IV (DP-IV).     

From supramolecular chemistry towards constitutional dynamic chemistry and adaptive chemistry

Supramolecular chemistry has developed over the last forty years as chemistry beyond the molecule. Starting with the investigation of the basis of molecular recognition, it has explored the implementation of molecular information in the programming of chemical systems towards self-organisation processes, that may occur either on the basis of design or with selection of their components. Supramolecular entities are by nature constitutionally dynamic by virtue of the lability of non-covalent interactions. Importing such features into molecular chemistry, through the introduction of reversible bonds into molecules, leads to the emergence of a constitutional dynamic chemistry, covering both the molecular and supramolecular levels. It considers chemical objects and systems capable of responding to external solicitations by modification of their constitution through component exchange or reorganisation. It thus opens the way towards an adaptive and evolutive chemistry, a further step towards the chemistry of complex matter.     

六配位磷化学和生命化学

氨基酸侧链作为调节N-磷酸基氨基酸的化学反应性时供给设备而起作用, 这一调节作用是通过磷酰基的参与而实现。     

Merging organometallic chemistry with polyoxometalate chemistry

A series of polyoxomolybdate-incorporated organometallic complexes has been obtained by reaction of [MBr(CO)5] or solvated M(CO)3+ ions (M = Mn or Br) with (nBu4N)2[Mo2O7] in methanol, sometimes in the presence of triols of the type RC(CH2OH)3 (R = Me or CH2OH). Their molecular structures are related to those of previously described polyoxoalkoxomolybdates through the formal replacement of fac-MoO2(OR)+ units by topologically equivalent fac-M(CO)3+ units. Representative pairs of structurally related clusters include [Mo2O6(OMe)4-Re(CO)32]2- and [Mo4O10(OMe)6]2-, [Mo2O4MeC(CH2O)32Mn(CO)3]- and [Mo3O6(OMe)MeC(CH2O)32]-, [Mo2O4HOCH2C(CH2O)32Mn(CO)32] and [Mo4O8(OEt)2MeC(CH2O)32], [Mo6O16(OMe)2MeC(CH2O)32-Mn(CO)32]2- and [Mo8O20(OMe)4-MeC(CH2O)32]2-. Although the frameworks of the majority of derivatives are based on tetranuclear units which display the common rhomb-like structure, the alternative cubane-type arrangement is observed in [Mo2O5(OMe)5M(CO)32]-.     

Putting the chemistry back into analytical chemistry

Aspects of the current status of and research in analytical chemistry are briefly discussed and the need for cost effective analytical procedures is emphasized. The present and future of a number of aspects of flow-injection analysis are considered. These include the basic theory, the kinetic features, the control features, time-based methodology, and the coupling of sample pretreatment with instrumentation. Several aspects of this latter topic are considered with particular reference to the flow-injection atomic spectrometry combination. Problems of kinetic mismatch between chemistry, manifold residence, and instrument operation are discussed and some possible solutions proposed including the use of closed loop manifolds.     

Can fluorine chemistry be green chemistry?

The roles of the element fluorine and its compounds in relationship to green chemistry and clean chemical manufacturing are considered.     

Contributions to the chemistry of carbenemetal chemistry

This paper provides a brief review of our researches on carbenemetal complexes. The main emphasis is on saturated heterocyclic bis(amino)carbene ligands, referred to here as electron-rich olefin- or ERO-derived ligands, as outlined in Sections 2 and 3. The following Section deals with Fischer-type carbene complexes, based on reactions of a transition metal substrate with an imidoyl chloride, Vilsmeyer reagent or Eschenmoser salt. The researches of Sections 2, 3, 4 have resulted in the synthesis, characterisation and selected reactions (including as catalysts) of carbene complexes of V, Cr, Mo, W, Mn, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt and Au in various oxidation states. A final Section describes some more recent work on C[(NCH₂Bu^t)₂C₆H₄–1,2], its adducts with M[(NCH₂Bu^t)₂C₆H₄–1,2] (M = Si, Ge, Sn, or Pb) and the biphenyl- bis(carbene), [C{NCH₂Bu^t}₂C₆H₃–3,4]₂.     

Indole chemistry

A new method of synthesizing lilolidenes (1,7-trimethyleneindoles), by reacting 1,2,3,4-tetrahydroquinolines with α-bromoketones, is given. PMR spectra of 2-substituted lilolidenes are obtained, and the effects of chemical substituents at positions 1 and 3 in the lilolidene ring on the chemical shift of protons is considered.     

Ethylenimine chemistry

2-Methyl-N-aminoethylenimine was synthesized by the classic Wenker method and by amination of 2-methylethylenimine with hydroxylamine-O-sulfonic acid in alkaline media. NMR spectroscopy indicated the formation of exclusively the trans-inverted isomer, the pyramidal stability of the heteroatom of which, as in N-aminoethylenimine [3–5], is preserved over a broad range of temperatures. The hydrazones of N-aminoethylenimine are characterized by an appreciably lower pyramidal stability of the nitrogen than that associated with participation of its unshared electron pair in p, conjugation with the electrons of the C=N bond. The inversion barrier in the hydrazones decreases symbatically with an increase in the degree of the indicated interaction. However, the decrease is insufficient to freeze free rotation about the nitrogen-nitrogen bond up to –80.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 45–48, January, 1971.See [1] for communication VI.     

Hot-atom chemistry

Research in the chemical effects of the nuclear transformations during the past 50 years is reviewed.     

Combinatorial chemistry

Rapid progress in molecular biology and the resulting ability to determine the activity of new compounds extremely efficiently have led to an enormously increased demand for test substances which cannot be satisfied by conventional synthesis methods. Combinatorial chemistry is a method that enables the efficient generation of large numbers of structurally diverse products. These products can be obtained as single compounds or in the form of defined mixtures. The synthesis is performed according to combinatorial principles (“produce all possible combinations of the reactants used”). The techniques and methods applied in combinatorial synthesis give rise to analytical problems: monitoring of reactions that take place on solid supports, structure elucidation with only minute amounts of material available or the characterization of substance mixtures. Examples from the authors’ laboratory illustrate how some of these problems can be approached. Received: 26 October 1996 / Revised: 24 February 1997 / Accepted: 26 February 1997     

环番(cyclophane)化学

本文综述了Cyclophane化合物的结构特征、合成方法以及主要化学性质。     

Systems chemistry

The study of complex mixtures of interacting synthetic molecules has historically not received much attention from chemists, even though research into complexity is well established in the neighbouring fields. However, with the huge recent interest in systems biology and the availability of modern analytical techniques this situation is likely to change. In this tutorial review we discuss some of the incentives for developing systems chemistry and we highlight the pioneering work in which molecular networks are making a splash. A distinction is made between networks under thermodynamic and kinetic control. The former include dynamic combinatorial libraries while the latter involve pseudo-dynamic combinatorial libraries, oscillating reactions and networks of autocatalytic and replicating compounds. These studies provide fundamental insights into the organisational principles of molecular networks and how these give rise to emergent properties such as amplification and feedback loops, and may eventually shed light on the origin of life. The knowledge obtained from the study of molecular networks should ultimately enable us to engineer new systems with properties and functions unlike any conventional materials.