Alkali Alkoxides Research Articles

α-Pyrones. II. The Synthesis of α-Pyrones From α,β-Unsaturated Aldehydes. Part II

It is shown that the reaction of acrolein with bromomalonate in the presence of an alkali alkoxide, leading to a 2-formylcyclopropane-1,1-dicarboxylate, may be applied to the steroid series; thus, a 20-methylene 21-aldehyde gives in excellent yield the corresponding cyclopropane derivative. The possibility of converting such systems to α-pyrones was investigated in the case of the acrolein adduct, diethyl 2-formylcyclopropane-1,1-dicarboxylate. While its cyclopropane ring could not be isomerized to an olefin with aluminum chloride or by reactions catalyzed by transition metals and while photolysis led to a dihydrofuran derivative, pyrolysis in high vacuum at 550–575° afforded directly an α-pyrone, ethyl coumalate. Evidence is put forward for the intermediacy of 3-ethoxycarbonyl-α-pyrone in this reaction.

Hydrogen transfer reaction from alcohols catalysed by rhodium carbonyl phosphine complexes

The hydrogen transfer from alcohols or alkoxides to olefins is catalysed by the RhCl 3-tertiary phosphines system. The complexes formed by reduction of Rh(CO)Cl(PR 3) 2 with alkali alkoxides in mild conditions have been investigated as well as the nature of catalytic hydrogenating species. The change in the catalytic activity with the nature of the phosphines have been correlated with the ability of Rh 0 phosphine complexes to abstract hydrogen from alkoxides.

Anionic graft polymerization of vinyl monomers on cellulose and polyvinyl alcohol

AbstractGraft polymers of acrylonitrile, methacrylonitrile and methyl methacrylate on polyhydroxy polymers such as cellulose and polyvinyl alcohol were prepared by anionic graft polymerization. The alkali alkoxide derivative of the polyhydroxy polymer backbone was used as initiator of polymerization. The graft polymerizations were carried out in liquid ammonia and other inert solvents at low temperature. Grafting was accompanied by considerable homopolymerization caused by chain transfer to monomer and to ammonia. The graft polymers were separated from homopolymers and unreacted polyhydroxy polymers by extraction with suitable solvents. The per cent of the grafted vinyl polymer increased with increase in the monomer and alkoxide concentration. No crosslinking occurred during the anionic graft polymerization, and soluble graft polymers were obtained.

アルカリアルコキシド触媒によるプロピレンオキシドの重合

アルカリアルコキシド触媒によるプロピレンオキシドの重合

A color reaction involving vinyl chloride containing polymers and pyridine

AbstractWhen a dilute pyridine solution of vinyl chloride polymers or copolymers is heated and a few drops of alcoholic hydroxide are added to the hot solution, a dark brown color develops. The response of vinyl chloride polymers in this reaction is much more intense than that of most other organic compounds, probably due to the conjugated double bonds produced in the main chain through the loss of hydrogen chloride. In addition to straight degradation of the polymer, the formation of an isocyanine dye is suggested by a mechanism which, besides pyridine and the polymer, involves the alkali alkoxide as a reactant.