Polymethylene derivatives

In 5,7-polymethylene derivatives of cyclohepta[c]furan-6-ones, the C=0 band is shifted from 1682 down to 1628 cm1 on lengthening the ansa chain from 7 up to 10 members (85MI3). 

Polymethylene derivatives of 4-carboxamido-5-aminoimidaz-oles, from which 8,9-polymethylenepurines were derived, were synthesized by the condensation of lactim ethers with a-amino-a-cyanoacetamide. In spite of the presence of an active methine group, the reaction proceeded exclusively on the amino group, as shown by the physicochemical properties of the resulting compounds and, in the... 

S,6-Polymethylene derivatives of selenopyrylium salts are formed when the related 1,5-diketones are treated with zinc selenide in methanolic HCl (94CHE503). 

Although preparation of cydodextrin catenanes of polymethylene derivatives and polycatenanes has been daimed, no data are furnished [68]. Since 1993, the only catenane example essentially reported has been the in situ formation of a fiself-assembled macrocyle, through Pd(II)(en) complexation of two threads, forms the [2]catenane 14 with -CyD at appropriate concentrations but the [3]rotaxane 15 with the wider y-CyD. Mass spectral characterization has also been provided for both spedes but none has been isolated. 

Phloroglucinol, according to Boehm , does not condense with formaldehyde at room temperature in the absence of added catalysts "When hydrochloric or sulfuric acid is added to the reaction mixture, a small quantitj of symmetrical hexahydroxydiphenylmethane (m.p 225 C) is formed, together with more complicated products. These products of further condensation are apparently" nuclear polymethylene derivatives iince on reduction of the crude acid condensation product with zinc dust and caustic soda, moncH, di- and tri-methy-lphloroglucinol as well as pbloro-... 

Koebner s research on the polymethylene derivative.s of 2 -cresol, (pages 177-179) led him to the belief that fusible resins consist of mixtures of cliain molecules of various lengths in which the nuclear phenolic carbon atoms are connected by methylene groups ... 

A wide variety of groups B separating the reactive sites have been employed. Apart from the aromatic ring shown for 100, a polymethylene chain and a bulky sugar alcohol derivative as in 102 have been used (174). 

Stoichiometric oxidation using TBHP and a 2 1 Ti tetraisopropox-ide-diisopropyl tartrate system can kinetically resolve racemic dialkyl-amino alcohols (Scheme 46) (106). The efficiency, which ranges from 0-95% ee, is largely dependent on the substrates. When methyl groups or polymethylene rings are used, the reaction proceeds to afford greater than 90% ee, whereas iV.iV-dibenzyl derivatives show little or no resolution. Use of natural (2/ ,3/ )-diisopropyl tartrate consistently gives R amino alcohols. 

Si,Si-Dimethyl-Sila-Substituted Derivatives of Polymethylen-bis-Trimethyl-ammonium Compounds with Curare-Like Activity... 

Photocycloaddition of C-P4-C. The photochemistry of coumarin and its derivatives has been the subject of numerous investigations, mainly as a consequence of its importance in biological systems [119-127], Irradiation of 7,7 -polymethylene-di(oxycoumarin)s at low concentrations yields only syn head-to-head and head-to-tail intramolecular cyclomers. Steric factors introduced in the corresponding molecule by methyl groups at the 4-positions of the coumarins led predominantly the syn head-to-tail cyclomer (Fig. 12). At higher concentrations, the amounts of intermolecular photoproducts increase as expected. 

Sodium has played an important role in the preparation of many polymethylene hydrocarbons and their derivatives. 

Taking into account the above considerations, the SPs were suggested to be ideal microbicides for topical use [105]. A number of potential candidate microbicides have been shown to inhibit virus attachment, fusion, and entry into host target cells for sexually transmitted infections. These include cellulose sulfate, poly(styrene 4-sulfonate), polystyrene sulfonate, polymethylene-hydroquinone sulfonate, naphthalene sulfonate polymer, and a carrageenan derived from seaweed (Carraguard) that may prevent viral entry. Several candidate compounds have already progressed to various stages of clinical trials [106]. Currently, some of them have been formulated and are in phase II/III clinical trials. 

The equation for the diffusion coefficient in a gaseous state, Dc, is the starting point for the derivation of an equation for diffusion coefficients in an amorphous solid state (S). The homologous series of n-alkanes is used as a reference class of chemical compounds which asymptotically reach an unlimited molecular chain in the form of poly methylene. The diffusion coefficient, DSji, is derived theoretically for a member of the series with j carbon atoms at infinite dilution in a matrix of a n-alkane with i carbon atoms in the molecule. In addition, the diffusion in polymethylene, which is considered as the reference structure for all polymers is also derived theoretically. 

Linear capsiacinoids with a C9/C12 chain are only trace constituents of capsicum oleoresin, which mainly contains branched capsaicinoids. The acyl moiety of these compounds is produced by the branched chain fatty acids pathway (Scheme 4.1) [30[. Depending on the nature of the amino acid that acts as the acyl starter precursor, different capsaicinoids are formed. Thus, capsaicinoids of the iso series such as CPS and homocapsaicin I are derived from valine and leucine via isobutyrylCoA and isovalerylCoA, respectively, while those from the anteiso series such as homocapsaicin II originate from isoleucine via 2-methylbutyrylCoA (Scheme 4.1) [31[. The polymethylene moiety of norcapsaicin has one less carbon than capsaicin. The... 

Treatment of polymethylene glycols with 50% sulfuric acid gives mixtures of cyclic oxides. Thus, 1,6-hexanediol yields a mixture containing 16% 1,6-, 25% 1,5-, and 65% 1,4-oxidohexane. In other instances, formation of the 1,4-oxido derivatives is also favored. ... 

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