Jugo Koketsu

Theoretical study on the thermal decomposition of pyridine

Semi-empirical PM3 molecular orbital calculations have been used to investigate the reaction pathways of pyrolysis of pyridine. All the transition states and intermediates of the reaction path were optimized. The probable pathways are estimated from the activation energies calculated and compared with known experimental results. The heats of formation of pyridine radicals are calculated to be 76.1, 80.6, and 79.5 kcal/mol for 2- (2A), 3- (3A) and 4-pyridyl radicals (4A), respectively. The weakest bonds on the radicals were assumed to be broken and gave the decomposition fragments successively.

Electrochemical polymerization of 3-aminopyridine and some characteristics

Abstract Poly(3-aminopyridine) was prepared by electrochemical polymerization of 3-aminopyridine in acetonitrile. The resulting polymer was characterized by TG-DTA, IR, 13 C NMR, UV-Vis spectroscopy, elemental analyses and cyclic voltammetry. The electrical resistivity of the polymer was in a semiconducting region. A photoresponse was also observed under illumination of a 400 W tungsten lamp.

Isolation of Hydroxyanthrones from the Roots of Rumex acetosa Linn

Rumexacetosa is a popular perennial plant, widespread in Japan, and its roots being used as a mild purgative and also as a medicine for curing cutaneous diseases. There are manyreports concerning the chemical components of various parts of Rumexacetosa. Fromits aerial parts, several flavonoids (vitexin,1* hyperin,2>3) rutin,3) and quercetin-3-D-galactoside4)) and aglycones of flavonoids (quercetin,4>5) kaempferol,5) and mylicetin5)) have been obtained. From its roots, some hydroxyanthraquinones (chrysophanol, physcion, emodin, aloe-emodin, co-acetoxy

Diaroyl tellurides: synthesis, structure and NBO analysis of (2-MeOC6H4CO)2Te--comparison with its sulfur and selenium isologues. The first observation of [MgBr][R(C=Te)O] salts.

A series of aromatic diacyl tellurides were prepared in moderate to good yields by the reactions of sodium or potassium arenecarbotelluroates with acyl chlorides in acetonitrile. X-ray structure analyses and theoretical calculations of 2-methoxybenzoic anhydride and bis(2-methoxybenzoyl) sulfide, selenide and telluride were carried out. The two 2-MeOC6H4CO moieties of bis(2-methoxybenzoyl) telluride are nearly planar and the two methoxy oxygen atoms intramolecularly coordinate to the central tellurium atom from both side of C(11)-Te(11)-C(22) plane. In contrast, the oxygen and sulfur isologues (2-MeOC6H4CO)2E (E = O, S), show that one of the two methoxy oxygen atoms contacts with the oxygen atom of the carbonyl group connected to the same benzene ring. The structure of di(2-methoxybenzoyl) selenide which was obtained by MO calculation resembles that of tellurium isologues rather than the corresponding oxygen and sulfur isologues. The reactions of di(aroyl) tellurides with Grignard reagents lead to the formation of tellurocarboxylato magnesium complexes [MgBr][R(C=Te)O].

Te-1-Acylmethyl and Te-1-Iminoalkyl Telluroesters: Synthesis and Thermolysis Leading to 1,3-Diketones and O-Alkenyl and O-Imino Esters

A series of Te-1-acylmethyl carbotelluroates was prepared in good isolated yields from the reaction of potassium carbotelluroates with α-haloketones in acetonitrile. Thermolysis of the telluroesters afforded vinyl esters in 20−50% yields, while treatment of the carbotellurorates with potassium t-butanolate led to 1,3-diketones in 30−75% yields with the liberation of black tellurium. The reaction of potassium carbotelluroates with α-haloaceto oximes gave O-acyl oximes in 50−70% yields via Te-1-iminomethylcarbotelluroates.

Reactions of group V organometalloidal compounds. Part VI. Ring opening of β-propiolactone and of epoxides with dialkylamino(dimethyl)-arsines

Treatment of β-propiolactone with dialkylamino(dimethyl)arsines at 80° in benzene gave dimethylarsenic 3-dialkylaminopropionates, formed by alkyl–oxygen bond fission. The addition reactions of dialkylamino(dimethyl)arsines with 1,1,1-trichloro-2,3-epoxypropane took place with normal fission of the epoxide ring to give 2-dialkylamino-1-trichloromethylethoxy(dimethyl)arsines. Although 1-chloro-2,3-epoxypropane was less reactive than the trichloro-compound, its mode of ring opening was the same. Degradation of the products of these reactions showed that the nucleophilic site in the aminoarsines was the nitrogen, rather than the arsenic atom.

Reactions of tris(dimethylamino)stibine with organic compounds

Tris(dimethylamino)stibine (I) reacts with aldehydes and ketones to give gem-diamines and enamines. The reaction with acetic anhydride gives NN-dimethylacetamide along with stibine oxide or tris(acetoxy)stibine. depending upon the conditions. Reactions of tris(dimethylamino)stibine (I) with carbon dioxide, phenyl isocyanate, and phenyl isothiocyanate afford the triscarbamato-, ureido-, and thioureido-derivative of stibine, as the result of insertion of the heterocumulenes across the antimony–nitrogen bonds in tris(dimethylamino)stibine.