The contents of this article are as follows : 1. Some new heat resistant polymers and the improvement methods of their processabilities. 2. Some new conductive polymers. 3. Some new polymers with chiral pendant. In each section the following three points are taken inconsideration as key point. (a) The starting compounds are easily available. (b) The synthetic methods must be new. (c) The obtained results are good or excellent. Any other research papers, which do not match with these three key points, are all omitted.
This article deals with the recent development in the synthetic study of hydrocarbon systems composed of a stable carbocationic unit as an acceptor and a neutral π-electronic unit as a donor. Synthesis of such systems, which are defined as “undissociable charge-transfer (CT) complexes”, is important in clarifying the intramolecular π-electronic interaction in the corresponding neutral systems and correlating it with the molecular geometry. The reported carbocations are roughly classified according to the dihedral angle between the donor and acceptor units as follows : [nm] cyclophane systems, 1, 8-disubstituted naphthalenes, janusene systems, 1, 2-disubstituted benzenes, and bicyclic systems related to triptycene or barrelene. The structural effects upon the observed intramolecular CT absorption, and upon the cation stabilization by through-space π-electron donation, are discussed together with the synthetic method for each of the cations. Some limited examples of the carbanions, which might have the intramolecular π-electronic interaction, are also surveyed.
As the analogues of acylimidazoles and β-aminoenones, the synthesis and the chemical properties of β-imidazolylenones were reviewed. The synthetic routes from β-haloenones, ynones and α, β-dibromoketones were described. By the reaction with pyrrolidine, the titled compounds are reactive as much as the β-haloenones. The quaternarization of the titled compounds by the treatment with methyl iodide increases the reactivity to the nucleophiles. As the nucleophiles, primary alcohols, phenols, thiols, amines, Grignard reagents and sodium borohydride are employed, and the replaced produts are obtained regioselectively. Also the titled compounds were shown to be useful for the starting materials of the various heterocycles by the treatment with the ambident nucleophiles such as hydroxylamine, hydrazines and ureas. The application of the synthetic procedure for β-chloroenones β-benzimidazolylenones gives β, β-diazolylenones, which were demonstrated as the good precursor of the acylketene derivatives. In conclusion, the titled compounds were shown to be much useful for the syntheses of β-substituted enones and various heterocycles.
This article describes the syntheses and the relationships between structure and antitumor activity of pyrrolizidine alkaloid (indicine N-oxide), lignan lactone glycoside (etoposide) and their related compounds from the standpoint of diastereomer and enantiomer. Total syntheses of indicine N-oxide, its diastereomer (intermedine N-oxide) and their enantiomers have been achieved in a totally stereospecific fashion through a sequence involving as the key steps (a) the enantioselective synthesis of retronecine and its enantiomer, (b) the enantioselective synthesis of (+) -trachelanthic acid and its enantiomer, and (c) a combination of each segments. Syntheses of all four possible diastereomers of etoposide and its aminoglycosidic analogues have been achieved via optical resolution of (±) -podophyllotoxin by glycosidation with D- and L-sugars.
In fluorine chemistry, considerable attention has been focussed on the search for the chiral synthetic tools for the preparation of functional materials such as ferroelectric liquid crystals and biopolymers. This article describes new catalytic reactions of the hydrolytic enzymes, i.e. the enzyme-assisted addition reaction to introduce a center of chirality into fluoro compounds.
Two classes of shark repellent factors have been isolated, guided by their ichthyotoxicity, from the defense secretions of two species of soles. One class comprises series of steroid monoglycosides, namely, pavoninins from a western Pacific species, Pardachirus pavoninus, and mosesins from the other in the Red Sea known as Moses sole, P. marmoratus. The other class consists of a series of surfactant peptides of 33 amino acid residues, pardaxins. This account deals with structure elucidation of these factors, where emphasis is put on the process from inference of chemical structures by spectroscopic and other customary techniques to their establishment by design of unconventional but firmly corroborative experiments. Diverse bioactivity of these factors is also discussed based on rationale with their amphiphilic structures, which are destined to interact with biological lipid bilayer membranes.
Tetramethylammonium hydroxide (TMAH) is a relatively strong base among organic compounds, and decomposes at 130-140°C into gaseous substances (Me3N, Me2O, MeOH, and H2O). TMAH has been prepared by alkali treatment of tetramethylammonium chloride (TMAC) obtainable from trimethylamine and methyl chloride, but use is made recently of developer electrolysis of TMAC in the presence of ion exchange membrane. The latter method gives rise to a highly pure TMAH aqueous solution free from chloride anions. TMAH currently finds some utilities in the production of highly functional materials such as developer for positive-working photoresist and the surface treatment of fibers, glasses, and plastics, and also as reagent for the methyl esterification of fatty acids and phospholipids, reagent for organic synthesis and preparation of catalysts, etc.