Reaction of polyhalopyridines 4. Reaction of mercaptopolychloropyridines with fluorine-containing xenon compounds

A method has been developed for the perfluoroalkylation of mercaptopolychloropyridines by the thermolysis of xenon(II) perfluoroalkanecarboxylates, obtained by the reaction of xenon difluoride and aperfluoroalkanecarboxylic acids, in the presence of the appropriate thiol. Perfluoroalkylthio derivatives of polychloropyridines have been synthesized. The fluorosulfonyl derivatives of tetrachloropyriidne and of tetrachloropyridine N-oxide were obtained by the action of XeF₂ on mercaptotetrachloropyridine dissolved in aqueous HF.For Communication 3 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 58–62, January, 1994.     

Acetoxyphenylketene. Reaction with biacetyl

The generation of acetoxyphenylketene (4) in the cold in the presence of biacetyl yields the single β-lactone $\text{12B}$, which undergoes a novel rearrangement to the tricyclic orthoester lactone $\text{11}$ above 130°.     

N-haloamidines. VI. Reaction of n-chloro-n'-benzenesulfonylbenzamidines with enamines

The reaction between N-chloro-N'-benzenesulfonylbenzamidines and ß,ß-disubstituted enamines affords N-(benzenesulfonyl)-N'- [(2-chloro-2-substituted-l-amino)-propyl]-benzamidines. When both ß-substi tuents are methyl groups the open chain adducts have been isolated and characterized; whereas, when one of the two substituents is a phenyl group, they have been characterized only by PMR because of the easy cyclization to 1-benzenesulfonyl-4, 5-dihydroimidazoles.     

Reaction of diisocyanates with alcohols. I. Uncatalyzed reactions

Because diisocyanates are widely used raw materials in the production of urethane elastomers and foams, it is of particular interest, to know the contribution of secondary reactions to the overall reaction between diisocyanates and polyether glycols, because of the well known influence of crosslinks on the physicochemical properties of polyurethanes. A mathematical method is suggested to calculate rate constants for the primary and secondary reactions, the hypothesis being that the allophanate group is the main secondary product. The method has been verified with experimental data obtained by reacting models. In addition, the influence of the [NCO]/[OH] ratio and of temperature on the formation of the allophanate group has been studied. The method has been applied to the reaction of 4,4′-diphenylmethane diisocyanate with poly(oxytetramethylene) glycol, a polyether glycol specifically designed for use in preparing polyurethanes. The results are in complete agreement with the experimental data.     

Crosslinking of starch xanthate. II. Reaction with polyacrolein

The reaction between polyacrolein bisulfite adduct and sodium starch xanthate in aqueous alkali gives a rapid viscosity increase and subsequent gelation. The magnitude and pattern of the viscosity development depend on the degree of substitution of the starch xanthates in the range of 0.12 to 0.45, varying from around 5000 cP centipoises (nongelling) for the lowest to more than 100 000 cP for the highest. The viscosity patterns developed with the more highly substituted xanthates show a minimum valley after a 20-30-min reaction. Analytical and spectral analyses of solid materials obtained from the ethanol precipitation of the gels indicate that the product is a monothiocarbonate stemming from the elimination of sodium hydrogen sulfide between a xanthate group of the starch and a hydroxyl group of the polyacrolein adduct. A hydrated form of polyacrolein does not react with starch xanthate under the same aqueous alkaline conditions.     

Reaction of alkylhydrazines. II. vic-disubstituted pyridines and pyridopyridazines

A series of 2,3-disubstituted pyridines and pyrido[2,3-d]pyridazines have been synthesized. The molecular structure of the compounds have been elucidated by using chromatography; ir, nmr, and mass spectrometry; and chemical methods, in particular metal complexation. The new compounds offer interesting chemistry and are envisaged to function as potential chemotherapeutic and pharmacodynamic agents.     

Reaction of diisocyanates with alcohols. II. Catalyzed reactions

In a previous work we reported a procedure to calculate rate constants for the primary and secondary reactions (urethane and allophanate formation, respectively) between isocyanate and alcohols. In the present paper the same procedure is applied to the catalyzed reaction, thus defining the selectivity for a series of catalysts.