The Effect of Chemical Changes in the Rubber Hydrocarbon on Its Oxidizability

1951 ◽  
Vol 24 (2) ◽  
pp. 229-231
Author(s):  
Jean Le Bras ◽  
Jacqueline de Merlier
Keyword(s):  
Double Bond ◽  
Carbon Atom ◽  
Maleic Anhydride ◽  
Type Ii ◽  
Methylene Carbon ◽  
Chemical Changes ◽  
Isoprene Unit ◽  
Methylene Carbon Atom ◽  
Substitutive Addition ◽  
Related Compounds

Abstract The hydrocarbon of rubber, which contains one ethylene linkage or double bond per isoprene unit, has such a structure that it is very sensitive to the action of oxygen, and the investigations of Farmer have shown clearly the part played by the α-methylene carbon atom in the process of oxidation. Since the rubber hydrocarbon can be made to react with compounds which unite directly with it, an attempt was made to find out what influence any changes of this kind might have on the oxidiazbility of rubber. The reagents chosen were saligenol and maleic anhydride. According to Cunneen, Farmer, and Koch, saligenol attaches itself to double bonds, with formation of a chromanic nucleus (I), the nature of which the present authors have examined and confirmed by ultraviolet spectrography of the compounds prepared. In the case of maleic anhydride, Delalande has shown that this compound and also related compounds, such as maleic imide, can combine according to the substitutive addition mechanism described by Alder, with the formation of a molecule of type (II). The reactions were carried out with exclusion of air, in accordance with the technique of Moureu and Dufraisse on benzene solutions of purified crepe rubber, and in the absence of a catalyst.

scholarly journals The effect of adenosine triphosphate on porphyrin excretion and on glycine metabolism in Rhodopseudomonas spheroides

1968 ◽  
Vol 106 (1) ◽  
pp. 185-192 ◽  
Author(s):  
A. Gajdos ◽  
M. Gajdos-Török ◽  
A. Gorchein ◽  
A. Neuberger ◽  
G. H. Tait
Keyword(s):  
Carbon Dioxide ◽  
Fatty Acid ◽  
Carbon Atom ◽  
Marked Effect ◽  
Methylene Carbon ◽  
Methylene Carbon Atom ◽  
Glycine Metabolism ◽  
Porphyrin Synthesis ◽  
Rhodopseudomonas Spheroides ◽  
Carboxyl Carbon

1. ATP, GTP, CTP and UTP at concentrations of 1mm markedly decrease the amount of coproporphyrin excreted by Rhodopseudomonas spheroides illuminated in a medium containing glycine, succinate and fumarate. 2. The effect of ATP is decreased if ethionine is also added to the medium. 3. Evidence is presented showing that ATP is taken up by the organisms from the medium. 4. ATP is shown to have a marked effect on the utilization of glycine. In the presence of ATP the incorporation of the methylene carbon atom of glycine into the fatty acid moieties of the phospholipids is greatly increased, and more of the carboxyl carbon atom is lost, probably as carbon dioxide. 5. ATP has little effect on the utilization of succinate or fumarate. 6. The possible significance of these results with regard to the control by ATP of porphyrin synthesis and excretion and glycine metabolism is discussed.

The stereochemistry of β -diketo complexes with trimethylplatinum iv. III. The crystal structure of trimethyl (acetylacetonyl-) 2:2'-bipyridyl platinum

1962 ◽  
Vol 266 (1327) ◽  
pp. 527-546 ◽  
Keyword(s):  
Crystal Structure ◽  
Carbon Atom ◽  
Three Dimensional ◽  
Crystal Structure Analysis ◽  
Method Of Least Squares ◽  
Methylene Carbon ◽  
X Ray ◽  
Methylene Carbon Atom ◽  
Active Methylene ◽  
Oxygen Atoms

The results of an X -ray crystal structure analysis of the crystalline complex, (CH 3 ) 3 Pt(CH 3 . CO . CH . CO . CH 3 )C 10 H 8 N 2 , formed by trimethylplatinum with acetylacetone and 2:2'-bipyridyl are presented. There are four monomeric molecules in a monoclinic unit cell having a = 14.863, b = 8.480, c = 13.749 Å, β = 99° 24' at 110±10 °K and space group P 2 1 / c . The atomic positions have been determined by three-dimensional analysis from observations collected at 100 to 120 °K. Refinement, including allowance for anisotropic thermal motion, was carried out by the method of least squares until the value of the residual R was 0.084. The platinum atom is octahedrally co-ordinated to three methyl groups in the cis configuration (Pt—C = 2.05 Å), to the two nitrogen atoms of the bipyridyl (Pt—N = 2.15 Å) and to the central or ‘active methylene’ carbon atom of acetylacetone (Pt—C = 2.36 Å). The oxygen atoms of the acetylacetone take no part in the co-ordination; this is the first example of a β -diketone acting as an unidentate ligand solely through a carbon atom. Comparison of the bond lengths in this and in the dimeric trimethyl 4:6-dioxononyl platinum suggests that in both compounds the β -diketone is in the keto and not the enol form; in the present compound the oxygen atoms are not chelated and the C=0 bonds are not parallel.

The Synthesis of 5,7-Dichlorocoumaran-3-one and Related Problems

1960 ◽  
Vol 13 (1) ◽  
pp. 95 ◽  
Author(s):  
WLF Armarego
Keyword(s):  
Acetic Acid ◽  
Carbon Atom ◽  
Intramolecular Cyclization ◽  
Phosphorus Pentoxide ◽  
Dichlorophenoxyacetic Acid ◽  
Methylene Carbon ◽  
Methylene Carbon Atom ◽  
Stage Synthesis ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Dichlorophenoxy Acetic Acid

5,7-Dichlorocoumaran-3-one has been prepared from methyl 2-hydroxy-3,5-dichlorobenzoate by a three stage synthesis. It could not be prepared by (i) intramolecular cyclization of 2,4-dichlorophenoxy- acetic acid or 2,4-dichlorophenoxyacetyl chloride or (ii) by the reaction of ω-bromo-2-hydroxy-3,5-dichloroacetophenone with bases. The reaction of 2,4-dichlorophenoxyacetic acid with phosphorus pentoxide in benzene gave 2,4-dichlorophenol, 2',4'-dichlorophenyl 2,4-dichlorophenoxyacetate, and diphenylmethane. By the use of 14C-labelled acids the methylene carbon atom of the diphenylmethane was shown to be derived from the methylene carbon atom of 2,4-dichlorophenoxyacetic acid. A possible mechanism is proposed for this reaction.

One-pot Synthetic Approaches for the Construction of Isochroman-4-ones and Benzoxazin-3-ones Using O,P-Acetals

Synthesis ◽  
2021 ◽  
Author(s):  
Akira Nakamura ◽  
Kouhei Yamamoto ◽  
Ryo Murakami ◽  
Norihito Kawashita ◽  
Kouichi Matsumoto ◽  
...  
Keyword(s):  
Carbon Atom ◽  
Intramolecular Cyclization ◽  
Heterocyclic Compounds ◽  
Functional Group ◽  
Methylene Carbon ◽  
One Pot ◽  
Methylene Carbon Atom ◽  
Synthetic Approaches ◽  
Sequential Reactions

A method for synthesizing six-membered heterocyclic compounds was developed based on the features of O,P-acetals. Sequential reactions of intramolecular cyclization between the methylene carbon atom of O,P-acetal and its electrophilic functional group (ester or protected carbamate) was followed by Horner-Wadsworth-Emmons (HWE) olefination with various aldehydes. The developed one-pot method yielded isochroman-4-one and benzoxazin-3-one derivatives with an alkylidene moiety.

scholarly journals Crystal structure of 1-butyl-3-{2-[(indan-5-yl)amino]-2-oxoethyl}-1H-imidazol-3-ium chloride

2018 ◽  
Vol 74 (11) ◽  
pp. 1665-1668
Author(s):  
Vidya Zende ◽  
Tejpalsingh Ramsingh Girase ◽  
Nicolas Chrysochos ◽  
Anant Ramakant Kapdi ◽  
Carola Schulzke
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Carbon Atom ◽  
Aromatic Ring ◽  
Methylene Carbon ◽  
Hydrogen Bonding Interactions ◽  
Methylene Carbon Atom ◽  
Molecular Salt

In the cation of the title molecular salt, C18H24N3O+·Cl−, an intramolecular C—H...O hydrogen bond stabilizes the almost coplanar orientation of the aromatic ring of the indane unit and the amide plane. In the crystal, the packing is dominated by intermolecular C—H...Cl hydrogen-bonding interactions that result in the formation of slab-like structures propagating along [010]. The slabs are linked by weak C—H...O interactions, forming layers lying parallel to (100). The methylene carbon atom of the indanyl substituent is disordered over two positions with a refined occupancy ratio of 0.84 (2):0.16 (2). The crystal studied was refined as a twin with matrix [1 0 0.9, 0 \overline{1} 0, 0 0 \overline{1}]; the resulting BASF value is 0.30.

Reactions of N-3′-furylbenzamide with some dienophiles

1979 ◽  
Vol 57 (3) ◽  
pp. 314-317 ◽  
Author(s):  
John N. Bridson
Keyword(s):  
Double Bond ◽  
Maleic Anhydride ◽  
Methyl Acrylate ◽  
Diels Alder ◽  
First Case ◽  
Dimethyl Maleate ◽  
Related Compounds ◽  
Alder Adduct

N-3′-Furylbenzamide gives a conventional Diels–Alder adduct with maleic anhydride but with dimethyl maleate and methyl acrylate further reactions take place at the enamide grouping of the initially formed adducts. Compounds have been isolated in which molecules of an alcohol, used as solvent, or the starting furan have added to the double bond of the 1:1 adducts. In the first case unstable alkoxyamides are formed; in the second stable 2:1 adducts result from a novel uncatalysed addition to the double bond of the enamide. The stereochemistry of these and related compounds is discussed.

Development of a Hydrazine-Catalyzed Carbonyl-Olefin Metathesis Reaction

Synlett ◽  
2019 ◽  
Vol 30 (17) ◽  
pp. 1954-1965 ◽  
Author(s):  
Tristan H. Lambert
Keyword(s):  
Double Bond ◽  
Organic Synthesis ◽  
Olefin Metathesis ◽  
Type I ◽  
Type Ii ◽  
Metathesis Reaction ◽  
Alternative Strategies ◽  
Potential Applications ◽  
Acid Catalyzed ◽  
New Strategies

Carbonyl-olefin metathesis is a potentially powerful yet underexplored reaction in organic synthesis. In recent years, however, this situation has begun to change, most notably with the introduction of several different catalytic technologies. The development of one of those new strategies, based on hydrazine catalysts and a novel [3+2] paradigm for double bond metathesis, is discussed herein. First, the stage is set with a description of some potential applications of carbonyl-olefin metathesis and a discussion of alternative strategies for this intriguing reaction.1 Introduction2 Potential Applications of Carbonyl-Olefin Metathesis3 Carbonyl-Olefin Metathesis Strategies4 Direct (Type I): Non-Catalytic5 Direct (Type I): Acid-Catalyzed6 Indirect (Type II): Metal Alkylidenes7 Indirect (Type III): Hydrazine-Catalyzed8 Conclusion

HINDERED CONFORMATIONAL ISOMERIZATION OF 9,10-DIHYDRO-9,9-DIMETHYL-10-METHYLENEANTHRACENES

1964 ◽  
Vol 42 (3) ◽  
pp. 565-571 ◽  
Author(s):  
D. Y. Curtin ◽  
C. G. Carlson ◽  
C. G. McCarty
Keyword(s):  
Room Temperature ◽  
Methyl Groups ◽  
Conformational Isomerization ◽  
Methylene Carbon ◽  
Methyl Group ◽  
First Order ◽  
Methylene Carbon Atom ◽  
Center Ring ◽  
Bromo Compound ◽  
Dibromo Derivative

While the n.m.r. spectrum of 10,10-dimethyl-9-methylene-9,10-dihydroanthracene (I) shows the geminal methyl group absorption as a sharp singlet the spectrum of the dibromo derivative, 10,10-dimethyl-9-dibromomethylene-9,10-dihydroanthracene (II) shows the methyl absorptions as two sharp well-separated peaks at room temperature which coalesce at 91°. 10,10-Dimethyl-9-phenylbromomethylene-9,10-dihydroanthracene (III), and the methyl ester (V) of IV show a broad geminal methyl spectrum at room temperature which separates to a doublet at lower temperatures and sharpens to a singlet at higher temperatures. Rate constants for the first-order processes responsible for the change in spectrum of II, III, and V have been calculated at the coalescence temperatures to be 57 (364 °K), 35 (305 °K), and 61 (300 °K) sec−1, respectively. The ΔH≠'s were used to extrapolate the rates to 305° to give values of 1, 40, and 100 sec−1, respectively. The process being studied is inferred to be the equilibrium between two boat conformations of the center ring in the dihydroanthracene system, rapid interconversion leading to identical environments for the two methyl groups. A comparison with the geometrically similar o,o′-disubstituted biphenyl racemization gives support for this explanation. A number of compounds with a proton and one substituent on the methylene carbon atom of I (substituents: bromine, chlorine, phenyl, carboxy, carbomethoxy, phenylmercapto) and also 10,10-dimethyl-9-phenylcarbomethoxymethylene-9,10-dihydroanthracene (XII) showed a single methyl absorption at room temperature. The methyl spectrum of the mono bromo compound VI did not broaden at temperatures down to 246 °K.

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