Effect Of Pyridine Research Articles

Studies of Organic Catalytic Reactions. III. The Hydration Mechanism of Nitriles to Amides with Nickel Catalysts

Abstract Benzonitrile, benzyl cyanide, acetonitrile and 2-cyanopyridine give the corresponding amides by the hydration with nickel catalysts and water. The effect of pyridine and thiophene on the hydration has been investigated. In general, the yield of amides increases upon the addition of a suitable amount of pyridine. On the contrary, the reaction is distinctly suppressed by the addition of thiophene. This fact is in striking contrast to the effect on the hydrogenation of nitriles. The correlation of the catalytic functions in hydration and the hydrogenation of nitriles has been studied, and the hydration mechanism with nickel catalysts has been discussed.

Effect of Nucleotides on Enzymic Browning in Potato Slices

Freshly cut slices darken as a result of oxidation of endogenous phenols in reactions catalyzed by polyphenol oxidase. Ascorbic acid, thiols, and other reducing substances prevent enzymic darkening (5, 17). Earlier studies showed that ATP substantially decreased browning in plant tissues, apparently via the reduction of quinones (14). ATP itself is not a reducing agent. The reducing compound is probably not ascorbic acid or GSH (12). In the presence of ATP, quinones are reduced under conditions favorable to oxidative phosphorylation (13). The mechanism by which ATP prevents browning is not known. -:This paper presents evidence in support of a hypothesis that DPNH serves as the reducing agent and that ATP is instrumental in maintaining a supply of DPNH for the reduction of quinones. Reduction of DPN in the presence of ATP had been demonstrated in minced pigeon breast muscle (8), phosphorylating animal mitochondria (3, 6), and subnmitochondrial particles (10, 16). Under our experinental conditions, DPNH may form from naturally present or added DPN, possibly via complex reactions found in animal systems. To our knowledge, the reduction of DPN induced by ATP has not yet been demonstrated in higher plants. The experimental work deals with the effect of pyridine and adenine nucleotides on enzymic browning of potato slices. In a phosphorylating system, the selected nucleotides could serve as possible precursors of ATP or of DPNH. The effects of the metabolic inhibitors, Amytal and antimycin A, were also investigated.

The effect of pyridine derivatives on the activity of crystalline ribonuclease

The influence of pyridine and some of its derivatives on the activity of ribonuclease (polyribonucleotide 2-oligonucleotidotransferase (cyclizing), EC 2.7.7.16) was investigated. Among the compounds examined pyridine showed the most striking activating effect at pH 5 in 0.2 M concentration. Nicotinamide, nicotinic acid and pyridine-β-carbonic diethylamide had a smaller activating effect, whereas isonicotinic hydrazide activated to a very slight extent. The activating effect of 0.6 M pyridine was about 210%. The activity-increasing effect of pyridine was similar when either poly- or oligonucleotide fractions of RNA were used as substrates. This effect of pyridine was reversible. It is suggested, that the disruption of the hydrogenbonds of the substrates was responsible for the activation.

Polarographic and spectrophotometric behaviour of rhodium in pyridine and γ-picoline solutions

Well-shaped polarographic steps are obtained with Rh 3+ in pyridine or γ-picoline solutions, suitable for a quantitative determination of Rh in the presence of Ir. Maxima in the absorption spectrum are found in the range 400–440 mμ, depending on the composition of the solutions. The effect of pyridine and γ-picoline as masking agents for the true polarographic step of Rh is studied. The electrode process appears to be, in both cases, a 2-electron reduction.

Studies on Ozonolysis. III-IV. IV. The Ozon olysis of Isosafrol in Carbon Tetrachloride. Part 2. The Reductive Decompositions of the Peroxides Obtained by the Ozonization, and the Effects of Pyridine and Methanol on the Ozonolysis of Isosafrol

前報において四塩化炭素中でイソサフロールをオゾン化するとき,反応系から収率よくヘリオトロピンをうるための還元分解方法につき検討した。しらべた還元剤の中ですぐれた収率をあげたのは硫酸第一鉄,硫酸第一鉄アンモニウムおよびヨウ化カリウムであったが,いずれの場合も反応系中のオゾニドの還元分解は完全に行なわれなかった。またオゾン化の反応様式を変化させる添加剤としてピリジンおよびメタノールを用い,その影響を検討したところ,還元分解後におけるヘリオトロピンの収率にかなりの向上が見られた。

Hemoglobin Studies. III. The Effect of Pyridine on the Combination of Heme with Carbon Monoxide1

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHemoglobin Studies. III. The Effect of Pyridine on the Combination of Heme with Carbon Monoxide1Akitsugu Nakahara and Jui H. WangCite this: J. Am. Chem. Soc. 1958, 80, 24, 6526–6528Publication Date (Print):December 1, 1958Publication History Published online1 May 2002Published inissue 1 December 1958https://doi.org/10.1021/ja01557a017RIGHTS & PERMISSIONSArticle Views68Altmetric-Citations19LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (284 KB) Get e-Alerts Get e-Alerts

Effect of pyridine on the reduction of oxygen in pulsating fields

Effect of pyridine on the reduction of oxygen in pulsating fields

Influence of Choline, Cystine and Methionine on Toxic Effects of Pyridine and Certain Related Compounds

SummaryPyridine alone or pyridine supplemented with either choline, cystine, methionine, nicotinamide or beta-picoline was fed to young rats on a high protein diet. Livers from rats dying from the effects of pyridine are enlarged and always exhibit a marked increase in water content. Livers from apparently healthy animals which have been on a pyridine diet show a nearly normal water content and are enlarged. Cystine and methionine afford protection against the effects of pyridine. The feeding of quinoline alone or quinoline supplemented with either choline, cystine, or methionine produced enlarged livers. Cystine and methionine increased survival time. Choline showed some protective effect. Cystine or methionine prevented the accumulation of water in the livers of rats fed quinoline. Choline had no effect.