Copolymerization reactivities and conductivities of some living polymers of p-substituted styrenes

A kinetic study in tetrahydrofuran of the addition of 1,1-diphenylethylene on para-substituted styrylcarbanions (with Cs⁺ as counterion) has given the reactivities of free ions and ion-pairs. For both species, the addition rate constant increased in the following sequence for the substituent of the phenyl ring: pH < p-CH₃ <p-CH₃O. It was also shown that in the same solvent, the dissociation constants of the polystyryl ion-pairs decreased with the electron-donating power of the substituent.     

Etude de la reactivite des coumarines—I : Regioselectivete des reactifs de grignard engages avec la coumarine

The various products obtained by the action of organomagnesium, compounds on coumarin result from 1.2-1.2 di-addition (phenolic alcohols) or 1.2–1.4 di-addition (ketophenols) or 1.4 mono-addition (dihydrobenzopyrones). The results show the importance of the nature of the halogen component of the Grignard reagent. A theoretical model allows regioselectivity of coumarine in relation to the group R and the halogene X to be evaluated.     

Magydardiendiol,diterpenoid with a new skeleton from magydaris panacifolia (umbelliferae).

Three new diterpenoids with a substituted α-cyclogeraniol skeleton have been isolated from the umbelliferae $\text{Magydaris panacifolia}$ (Vahl) Lange, for which the names of magydar-2,13-dien-11,17-diol, $\text{1}$, magydar-2,10 (20), 13-trien-17-ol, $\text{2}$, and magydar-2,10(20), 13-trien-17-yl acetate, $\text{3}$, are proposed. The structures of these substances have been deduced from spectroscopic and chemical data.     

Condensation metallosupramolecular polymers containing main-chain 2,2′-bipyridine and 2,2′:6′,2″-terpyridine moieties

Methods of preparing diverse metallosupramolecular polymers containing 2,2′-bipyridine and 2,2′:6′,2″-terpyridine moieties in main chains and their properties have been considered and analyzed. It has been shown that these polymers offer new possibilities for the design of materials possessing valuable specific characteristics.     

Analogs of pyrimidine mono- and polynucleotides

The corresponding monophosphates, cyclophosphates, and , -diphosphates were obtained by phosphorylation of 1-(1, 4-dihydroxy-2-pentyl) thymine, 1-(1, 3-dihydroxy-2-propyl) uracil, and their derivatives with selective protection of one of the hydroxyl groups. 2-Cyanoethyl phosphate (CEP) in the presence of N, N-dicyclohexylcarbodiimide (DCC), polyphosphoric acid, and pyrophosphoryl chloride were used as phosphorylating agents. The dependence of the yields of the products of phosphorylation of 1-(1, 4-dihydroxy-2-pentyl) thymine with CEP on the ratio of the reacting substances and the reaction time was studied. The monophosphates were cyclized under the influence of DCC. In the case of 1-(1, 3-dihydroxy-2-propyl) uracil 1-phosphate a dimeric phosphate was obtained in addition to a cyclophosphate. The acid hydrolysis of the cyclophosphates was investigated.See [1] for communication V; see [2] for a preliminary communication.Deceased.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 678–683, May, 1978.     

Synthesis of New Iron-Containing Carbon Cages by Reaction of C60 Fullerene with Ferrocene

Reaction of C₆₀ fullerene with ferrocene in the presence of aluminum chloride and aluminum in an inert atmosphere gave ferrocenyl-substituted fullerene 2C₆₀ ·1.5(C₅H₅)₂Fe ·3H₂O. The product is a thermally stable iron-containing carbon cage in which the intersphere cavity is formed by three C₆₀ polyhedra and is closed by cyclopentadienyl ligands via formation of four carbon-carbon bonds.     

Chemical instabilities during oxidation of 1,4-naphthalenediol in a homogeneous medium: II. Thermodynamic analysis and mathematical modeling

A possible mechanism of 1,4-naphthalenediol oxidation in the oscillatory regime has been considered, and a mathematical model describing the kinetics has been developed. Based on a thermodynamic Lyapunov function, it has been shown that the source of chemical instabilities is in the existence of autocatalytic steps and dynamic feedbacks. Qualitative analysis and numerical solution of the set of differential equations that model the reaction kinetics have been performed. The character of the stationary state and the possibility of bifurcations have been determined. The mathematical model satisfactorily describes the processes occurring in the system.     

PHOTOTROPISM–THE NEED FOR A SENSE OF DIRECTION?

Abstract— The ill defined nature of the conceptual framework used to guide research on phototropism is a handicap to progress. It is argued that some of the central concepts, such as the stimulus perception-transduction-response chain, have not given a useful sense of direction. Likewise the arguments as to whether hormones are involved in phototropism have now become a distraction. A constructive phase is now needed, building on an agreed framework. There is an urgent need to identify the universal elements of phototropism and to distinguish those elements from the ones which apply only in specialised cases.