Showing papers on "Pyrazoline published in 1979"

The introduction of alkylidene substituents into the 4-position of the 3,3,5,5-tetramethyl-Δ1-pyrazoline nucleus by the thioketone plus diazoalkane reaction: synthesis of tetrasubstituted episulphides and alkenes

Abstract: A wide range of 4-alkylidene-3,3,5,5-tetramethyl-Δ1-pyrazolines (2), potential precursors of unsymmetrical trimethylenemethane biradicals, can be made through the reaction of thioketone (3b) with various diazo compounds (9) or the reaction of diazo compound (3e) with thioketones. In some cases, depending on the nature of the substituents X and Y, thiadiazoline and/or episulphide intermediates can be isolated but in others the alkene is obtained directly. Reaction of the thioketone (3b) with the diazo compound (3e) gives the thiadiazoline (13) which, when heated in the solid state and then treated with trimethyl phosphite gives the unusual, highly crowded olefin (12). A byproduct of the reaction of thioketone (3b) with diazodicyanomethane is the novel azomethine imine (11).

On the syntheses and the optical properties of optically active 2-pyrazoline compounds

Abstract: Optically active 2-pyrazolines were synthesized and their optical properties were studied using various spectroscopic techniques to investigate the effects of substituents at the 3 and 5 positions of the 2-pyrazoline ring on their optical activity It was found that in the case of 5-substituted-1,3-diphenyl-2-pyrazoline derivatives, the substituent at the 5 position has considerable influence on the optical activity, whereas in 3-substituted-1,5-diphenyl-2-pyrazoline derivatives, the substituent at the 3 position has no such influence

Diaryl substituted pyrazoline carboxanilides, processes for preparing them, insecticidal compositions and uses thereof, and intermediates therefor

Abstract: Compounds of formula where R' and R 2 are H, halogen, CF 3 ; R 3 is alkyl (C, - C a ), phenyl; R 4 is H, alkyl (C, - C e ); and compositions comprising them useful as insecticides.

Synthesis of poly[1,3-diphenyl-5-(p-vinylphenyl)-2-pyrazoline]

Abstract: Introduction Interest has been expanding in 1,3,5-triphenyl-2pyrazoline (TPP) and its derivatives. Recent studies have shown that these compounds possess some interesting physical and chemical properties. They are strongly fluorescent (LEAVER, RIVETT 1974; STRAHLE et al. 1976), for which the nearly planar conjugated n-system Ar-N-NZC-Ar in the pyrazoline ring is responsible. They are photoconductive, and readily form a glassy state at near or above room temperature which is kept for quite a long period of time (SANO et al. 1976). They have been used as fluorescent whitening agents for wool and certain synthetic fibers (WAGNER et al. 1966). Some derivatives of TPP have found a successful application for use in electrophotography (MELZ et al. 1977).

Polarographic behaviour of some potential antidiabetics: 4-arylhydrazono-3-methyl-1-phenyl-2-pyrazoline-5-ones

Abstract: Polarographic reduction of 4-arylhydr:uono-3-methyl-l-pbenyi-3-pyratoline-S-ones takes place in a single four-electron, well-defined, diffusion-controlled, irreversible wave in lO.0725M, O.OO725M H.SO, as well as in buffers. Nitro substituted derivatives exhibit one more four-electron wave at less negative potentials. Methyl, chIoro, methoxy, ethoxyand bromo groups show positive polarographic ortho shift. The effect of substituents on the half-wave potential has been interpreted in the terms of Hammett equation.

Existence of a stable nh form of 4‐pyrazoline in aromatization of 3,3‐disubstituted pyrazolidines to pyrazole. mechanism of the reaction

Abstract: Aus dem Phenylhydrazon (I) erhalt man mit Ma1ein- und Fumarsaureester (II) die Pyrazoline (III), analog entsteht aus (IV) das Pyrazolin (V).

On the syntheses and the optical properties of optically active 2-pyrazoline compounds

Abstract: Optically active 2-pyrazolines were synthesized and their optical properties were studied using various spectroscopic techniques to investigate the effects of substituents at the 3 and 5 positions of the 2-pyrazoline ring on their optical activity. It was found that in the case of 5-substituted-1,3-diphenyl-2-pyrazoline derivatives, the substituent at the 5 position has considerable influence on the optical activity, whereas in 3-substituted-1,5-diphenyl-2-pyrazoline derivatives, the substituent at the 3 position has no such influence.