Recent reviews. 61.

Reviews are listed in order of appearance in the sources indicated. In multidisciplinary review journals, only those reviews which fall within the scope of this Journal are included. Sources are listed alphabetically in three categories: regularly issued review journals and series volumes, contributed volumes, and other monographs. Titles are numbered serially, and these numbers are used for reference in the index. Major English-language sources of critical reviews are covered. Encyclopedic treatises, annual surveys such as Specialist Periodical Reports, and compilations of symposia proceedings are omitted. This installment of Recent Reviews covers principally the early part of the 2001 literature. Previous installment: J. Org. Chem. 2001, 66(7), 2538-46.     

The tube electrode and e.s.r.

The convective diffusion equation for the downstream distribution of products and intermediates produced on a tube electrode under conditions of laminar flow is solved. For distances which are large compared to the thickness of the electrode, an analytical solution in real space can be found. The solution of the equation has been applied to an apparatus in which the intermediates and products are detected by e.s.r. The species are transported by laminar flow from the electrode through an e.s.r. cavity. Results are presented for two systems and are found to be in good agreement with the theory.     

Interfacial polycondensation. I.

Interfacial polycondensation is a rapid, irreversible polymerization at the interface between water containing one difunctional intermediate and an inert immiscible organic solvent containing a complementary difunctional reactant. It is based on the Schotten-Baumann reaction in which acid chlorides are reacted with compounds containing active hydrogen atoms (—OH, —NH and —SH). A large number of polymers (heat-sensitive and infusible as well as stable and meltable) can be prepared. The method has been applied to the preparation of polyurethanes, polyamides, polyureas, polysulfonamides, and polyphenyl esters. Interfacial polycondensations are run in simple, open laboratory equipment with or without stirring. With suitable agitation granular or powdered polymers with high molecular weight are prepared at room temperature and isolated within a few minutes. The intermediates need not be absolutely pure or in balance nor is a quantitative yield needed in order to obtain high polymer. The major variables in the interfacial polycondensation process are discussed and the laboratory techniques and principles are contrasted with melt polycondensation.     

Education in analytical chemistry in the U.S.S.R.

Analytical Chemistry is taught at over 600 schools of higher education in the U.S.S.R. Contents of general and special courses are described in this article. The main problems and objectives of education at universities are mentioned.     

Post-gamma-irradiation grafting of polypropylene. Part II. Butadiene: E.S.R. experiments

ESR spectra of gamma irradiated annealed and quenched forms of polypropylene film have been studied at the temperatures used for post-irradiation grafting experiments with butadiene, described in Part I. On warming from low temperature there is radical loss by termination and some radical transformation to radicals with optimum stability in annealed polypropylene at approximately 45°C. These radicals, which may be allyl type, are sited at the crystal faces, and decay more rapidly at higher temperatures in annealed polypropylene; in quenced polypropylene their concentration never exceeds one third the optimum observed in annealed polypropylene. Correlation with the grafting experiments suggests that allyl radicals are important for long-term grafting. Effects on the ESR spectrum of adding butadiene to the system show that in the long-term butadiene adds exclusively to the allyl radicals and that alkyl radicals still present at that stage are precursors to the allyl radicals. They do not react directly with butadiene presumably because they are sited in the inaccessible crystal core. Experiments at lower temperature show that butadiene does react with alkyl radicals in accessible regions.     

Computer system for structure recognition of polyatomic molecules by i.r., n.m.r., u.v. and m.s. methods

A system of algorithms and programs for the recognition of the structures of polyatomic molecules by means of i.r., n.m.r., u.v. and mass spectra is described. Examples of structures identified are cited. The results are promising and suggest that the system could be used for the identification of complex organic compounds.     

Le Groupe de Recherche du C.R.N.S. Application des Reactions Nucleaires a l'Analyse Chimique G.A.R.N.A.C.

In this article the research topics dealt with at Research Group for Applications of Nuclear Reactions to Chemical Analysis (GARNAC) are described. Particular emphasis is laid on the main contribution of the GARNAC to the development and the evolution of charged particle activation analysis, evolving with the analytical studies performed and with the scientific and technical progress realized in material and semiconductors science.      

Crystal structures of synthetic analgetics. V. Dextromoramide.

The molecular and crystal structure of dextromoramide has been determined by X-ray methods. The crystals are orthorhombic, space group P212121 with unit cell dimensions a = 9.720(4) A; b = 12.226(3) A; c = 18.381(3) A. The structure was determined by direct methods and the model refined to an R-value of 0.036 for 1788 observed reflections. The mean e.s.d.'s in bond lengths and angles are 0.004 A and 0.3, respectively. The morpholine moiety is nearly in antiposition relative to the quaternary carbon atom C6, the pertinent angle C6 - C7 - C9 - N2 being - 159.4. This conformation is similar to that previously reported for the bitartrate of the title compound. The pyrrolidine ring has the envelope conformation and the amide group is strictly planar. The conformation of some acyclic analgetics are discussed.     

Cover Picture: Angew. Chem. Int. Ed. 20/2002

The cover picture shows a series of ¹⁹F NMR spectra taken every hour during the monitoring of a time‐course experiment after addition of 5′‐fluoro‐5′‐deoxyadenosine (5′‐FDA) to a cell‐free extract of Streptomyces cattleya. This bacterium has the unusual capacity to biosynthesise organofluorine compounds from inorganic fluoride. The ¹⁹F NMR spectra illustrate that 5′‐FDA is a true intermediate in the biosynthesis of fluoroacetate and 4‐fluorothreonine. Other intermediates such as fluoroacetaldehyde are also observed for the first time. In a separate experiment, inorganic fluoride was converted into fluoroacetate, thus indicating that all of the enzymes involved in the fluoroacetate biosynthesis pathway are active in the cell‐free extract. These experiments report the first cell‐free biotransformations of inorganic fluoride into fluoroacetate, the most ubiquitous organic fluorine natural product, and pave the way for a biotechnological approach to organofluorine synthesis. Full details are described by O'Hagan and co‐workers on p. 3913 ff.     

Comment on "Adsorption of naphthalene on zeolite from aqueous solution" by C.F. Chang, C.Y. Chang, K.H. Chen, W.T. Tsai, J.L. Shie, Y.H. Chen

A paper contributes not only by its originality and creativity, but also by its continuity and development toward subsequent research. Referencing and quotation accuracy are an important part of a scientific article. This study presents a literature review concerning the precision of 50 first authors' publications, which originally cited Ho's pseudo-second-order kinetic expression paper in kinetics model for solute sorption on various sorbents. This model applies to a range of solid-liquid systems such as metal ions, dyestuffs, herbicides, oil, and organic substances in aqueous systems onto various sorbents. In addition, citations of Lagergren and Elovich rate equations are also discussed. This comment offers information for citing the original idea of Ho's pseudo-second-order kinetic expression and Lagergren's pseudo-first-order kinetic equation. It is also suggested that the cited paper should be accurately quoted.     

Unsymmetrically substituted furoxans. VIII. Chloromethylfuroxans

The two isomeric chloromethylfuroxans have been prepared. Their structures, thermal equilibration and reaction toward thiophenoxide ion are discussed. Kinetics of the 4-methyl — 3-methyl isomer thermal conversion are also reported.     

Azidinium-Salze. 23. Mitteilung. Photolyse heterocylischer Azidinium-Salze

Photolysis of Heterocyclic Azidinium Salts The photochemistry of some azidinium salts was investigated. Their photolusis led to a large variety of products which were isolated and identified. Reaction mechanisms involving singlet and triplet nitrene intermediates are discussed to explain the product formation.     

60th Birthday of Prof. Dr. Dr. h.c. Heino Finkelmann

This section contains news of the macromolecular community all over the world. Articles about, for example, people, projects, and market trends are welcome. Suggestions should be sent to the editorial office of the Macromolecular journals, preferably by E‐mail to macromol@wiley‐vch.de. The editorial office decides which articles will be published.     

E.H.M.O. calculations on the actual conformations of thymine photodimers

Extended Hückel molecular orbital calculations have been carried out on the actual structures of some photodimers of uracil and thymine. The results are compared with those derived for some postulated models by Jordan and Pullman, and the differences between the real structures and the models are examined.     

Carbon-13 n.m.r. spectroscopy of some Strychnos alkaloids

¹³C N.m.r. spectra have been determined for strychnine and a series of fourteen derivatives. The assignments are based on previously established data and on off-resonance decoupled spectra. The shifts resulting from the alterations in molecular structure are discussed and explained, in part, as a consequence of conformational changes. This detailed study indicates that changes are required in some previously published assignments.     

13C n.m.r. spectra of quercetin and rutin

The noise-decoupled and gated-decoupled ¹³C n.m.r. spectra of quercetin and rutin are studied and assignments are proposed. The previous assignments of carbons 2 and 4′, carbons 5 and 9, carbons 6 and 8 have been reversed.     

Eine neue Fulvensynthese. 4. Mitteilung

Fulvenes are prepared by condensation of sodium cyclopentadienide with x-acetoxy-x-chloro-hydrocarbon derivatives, followed by elimination of acetic acid with triethylamine. The yields are approximately 60% for 6-alkylfulvenes and similar to those of the classical synthesis for 6, 6-polymethylenefulvenes. The reaction is carried out at low temperatures and under water-free conditions. The purification of the fulvenes is simple.     

Experimental Resolution and Brand Profile in F.T.-I.R. Spectroscopy

The minimum possible number of sampling points (N) to achieve rapid and accurate scan and the best I.R.-F.T. spectra in terms of resolution, height (H) half height band width (HH) are discussed. The experimental resolution, for a particular number of data points, was measured from the distance of any newly evolved peak from its closest neighbor when increasing N in a water vapour interferogram; the experimental curve is close to the theoretical one. H and HH of any peak are found to increase and decrease respectively when the optical path is enlarged up to a certain limit and thereafter, they become almost constant. Taking informations with further values of N merely adds noise with no sign of improvement in the spectra.     

Polysiloxane dizwitterionomers. II. Morphology

Small-angle x-ray and electron microscopy were used to study the morphology of polysiloxane dizwitterionomers. As in other polyelectrolytes, the zwitterions aggregate into ionic domains. In this case the domains are lamellar in nature and are in parallel arrays. The distance between these ionic regions is inversely proportional to the dizwitterion concentration in the polymer; their thickness is independent of the ionic concentration and is about 7 Å.