Showing papers on "Pyrazoline published in 1974"
TL;DR: In this article, the thermolysis of 3,3,5,5 and 5-tetramethyl-4-methylene-1-pyrazoline (1) proceeds at 1/63 the rate of 4-methylen-1, pyrazoline, and activation parameters, log (k/s−1)
Abstract: The thermolysis of 3,3,5,5-tetramethyl-4-methylene-1-pyrazoline (1) proceeds at 1/63 the rate of 4-methylene-1-pyrazoline. The activation parameters, log (k/s−1) = (15.53 ± 0.3) − (40.7 ± 0.4)/θ wh...
36 citations
TL;DR: In this paper, the effect of solvent and structure on the stability to light of a series of 1,3-diphenyl-2-pyrazolines has been studied.
Abstract: The effect of solvent and structure on the stability to light of a series of 1,3-diphenyl-2-pyrazolines has been studied. The major photochemical reaction observed is dehydrogenation to the corresponding 1,3-diphenylpyrazole unless the 5-position is disubstituted when, as in the case of 1,3,5,5-tetraphenyl-2- pyrazoline, photo-oxidation, with either retention or destruction of the heterocyclic ring, occurs. Evidence is presented that singlet oxygen may be involved in the photodehydrogenation of 1,3- diphenyl-2-pyrazoline. The observation that the presence of bulky groups in both the 4- and 5-positions improved both the fluorescence efficiency and the stability to light of the 1,3-diphenyl-2-pyrazoline molecule may have significance for the design of pyrazoline whitening agents. Dehydrogenation of the same series of pyrazolines with chloranil has been studied in order to determine the effect of substituents on the yield of pyrazole.
31 citations
TL;DR: In this article, the electron impact induced fragmentation of Cr(CO) 5 and Fe(CO 4 ) complexes with heterocyclic carbene ligands derived from pyrazoline, imidazoline, triazoline and tetrazoline is described.
27 citations
TL;DR: Simulated solar irradiation of wool, silk, bovine serum albumin and apomyoglobin in the presence of radioactively labelled fluorescent whitening agents of the bistriazinylaminostilbene and pyrazoline types results in the irreversible binding of radioactivity to the protein.
Abstract: Simulated solar irradiation of wool, silk, bovine serum albumin and apomyoglobin in the presence of radioactively labelled fluorescent whitening agents of the bistriazinylaminostilbene and pyrazoline types results in the irreversible binding of radioactivity to the protein. This photochemical reaction occurs both in the solid state and in aqueous solution, and is believed to result in the formation of a covalent bond between the whitener (or a photodecomposition product) and the protein.
13 citations
Patent•
21 Jun 1974
TL;DR: In the management of inflammatory conditions such as rheumatoid arthritis, these compounds are indicated in the management as discussed by the authors, such as Crohn's disease and Crohn lymphoma.
Abstract: Compounds of the formula; WHEREIN R1 is alkyl or aryl; R2 is aryl; and R3 is alkyl, alkoxy, halogen, trifluoromethyl, carboalkoxyl, cyano, and the like. These compounds are indicated in the management of inflammatory conditions such as rheumatoid arthritis.
9 citations
Patent•
22 Aug 1974TL;DR: In this article, a process for the preparation of 3,5-disubstituted pyrazoles is described, which involves: A. The reaction of a methyl ketone, such as acetophenone or an appropriate derivative thereof, with an appropriate aldehyde such as benzaldehyde in the presence of base to form a 1,3-dissubstitutive α,β-unsaturated ketone such as chalcone or a substituted chalecone, B. The acidification of the acidified reaction mixture with hydrazine, followed by treatment
Abstract: There is provided a process for the preparation of 3,5-disubstituted pyrazoles which involves: A. the reaction of a methyl ketone, such as acetophenone or an appropriate derivative thereof, with an appropriate aldehyde, such as benzaldehyde in the presence of base to form a 1,3-disubstituted α,β-unsaturated ketone, such as chalcone or a substituted chalcone, B. the acidification of said α,β-unsaturated ketone, followed by treatment of the acidified reaction mixture with hydrazine to form a disubstituted pyrazoline, and C. the catalytic dehydrogenation of said pyrazoline to yield the desired 3,5-disubstituted pyrazole.
8 citations
TL;DR: In this paper, the pyrazoline derivative of O-methylperezone was irradiated by ultraviolet light, yielding tricyclic compounds (4, 5, 6) and tetra substituted compounds (3, 6).
Abstract: Irradiation of the pyrazoline derivative of O-methylperezone (2) by ultraviolet light yielded the tricyclic compounds (4) and (5), the tetra substituted compound (3) and the tetracyclic compound (6).
6 citations
TL;DR: Aus 1.Cyan-isothiochroman bzw. ‐isochroman sind durch Umsetzung mit Chloracetonitril 1.
Abstract: Aus 1‐Cyan‐isothiochroman bzw. ‐isochroman sind durch Umsetzung mit Chloracetonitril 1‐Cyan‐1‐cyanmethyl‐isothiochroman (1a) bzw. ‐isochroman (1c) zugänglich, die sich durch Verseifung in 2,5‐Dioxo‐pyrrolidin‐(3‐spiro‐1′)‐isothiochroman (2a) bzw. ‐isochroman (2c) überführen lassen. – 1‐Cyan‐isothiochroman‐1‐carbonsäuremethylester (4) und Hydrazin können zu 3‐Amino‐5‐oxo‐pyrazolin‐ bzw. 3‐Imino‐5‐oxo‐pyrazolidin‐(4‐spiro‐ 1′)‐isothiochroman (6 bzw. 5) kondensiert werden.
5 citations
TL;DR: In this paper, the effect of substituents attached to the heterocyclic ring on the polarographic behavior of heterocycles is analyzed, and the results of the analysis are correlated.
Abstract: The literature data on the principles of the electrochemical reduction of heteroethylene and heteroparaffin compounds (pyrazoline, diazepine, diaziridine, pyran, pyridazone, aziridine, oxaziridine, and other derivatives), cyclic anhydrides, imides, and hydrazides of acids on a dropping mercury electrode are correlated. In addition, the effect of substituents attached to the heterocyclic ring on the polarographic behavior of heterocycles is analyzed.
4 citations
Journal Article•
3 citations
TL;DR: In this article, a cyclization of the 4-methyl-3-thiosemicarbazone of diethyl acetylsuccinate (1a) by the action of ammonium hydroxide followed by acidification afforded ethyl 3methyl-1-methylthiocarbamoyl-5-oxo-3 -pyrazoline-4-acetate (11a') 3-Methyl-1.
Patent•
10 Oct 1974
TL;DR: In this article, the triaryl-pyrazoline series of formula (I) indicators are used for rapid visual determn. of the dosage with high power gamma-plants and electron accelerators and for monitoring the dosage in industrial irradiation processes, e.g. for cold sterilisation of medical equipment.
Abstract: These indicators comprise non-halogenated polymer films contg. a light-fast fluorescent dyestuff of the triaryl-pyrazoline series of formula (I) (in which R1 and R2 are opt. substd. aryl; R3 is an isomeric naphthoylenobenzimidazole of formula (II) or phenylnaphthalimide gp. of formula (III). They are suitable for rapid determn. of the dosage with high-power gamma-plants and electron accelerators and for monitoring the dosage in industrial irradiation processes, e.g. for cold sterilisation of medical equipment. It is possible to combine rapid visual determn. of dosage with measurement by an objective parameter.
Journal Article•
01 Jan 1974
TL;DR: The adduct (13)[or (16)], obtained from the reaction of 4-isopropylidene-3-oxo-7β-phenoxyacetamidocepham with hydrazine, readily undergoes dehydration to give the title pyrazoline (2).
Abstract: The adduct (13)[or (16)], obtained from the reaction of 4-isopropylidene-3-oxo-7β-phenoxyacetamidocepham (1) with hydrazine, readily undergoes dehydration to give the title pyrazoline (2). N-Bromosuccinimide converts the derivative (2) into the 8-bromo-pyrazoline (6), which is transformed into the 8-methoxy-pyrazoline (7) by silver(I) perchlorate in methanol. The 8-acetoxy-pyrazoline (8), formed by the action of lead tetra-acetate on the pyrazoline (2), affords the 8-hydroxy-pyrazoline (9) in the presence of methanolic triethylamine or potassium t-butoxide in tetrahydrofuran. With potassium t-butoxide in t-butyl alcohol, it yields the epimeric alcohol (16). Compounds (7)–(9) lose nitrogen when irradiated to give the cyclopropyl derivatives (18)–(20), respectively, Iron(III) chloride converts the cyclopropanol (20) into the carbinolamine (24).The pyrazoline (2) reacts with mercury(II) acetate in acetic acid to give the pyrazolinylazetidine diacetate (28), which slowly decomposes with loss of nitrogen to the enone (29) at room temperature.