Diene Component Research Articles

Investigations on the mechanism of radiation induced crosslinking in ethylene‐propylene‐diene terpolymers

AbstractThe radiation induced crosslinking, double bond consumption, and radical formation of ethylene‐propylene‐copolymers (EPM) and ethylene‐propylene‐diene terpolymers (EPDM), containing either 5‐ethylidene‐2‐norbornene or dicyclopentadiene as the diene component, were investigated. The diene content was found to increase crosslinking as well as chain scission, 5‐ethylidene‐2‐norbornene being more efficient than dicyclopentadiene. The ESR‐spectra of EPM and EPDM at −196°C are almost identical, showing alkyl radicals corresponding to the ethylene and propylene component. At −50°C in EPDM allyl type radicals characteristic of 5‐ethylidene‐2‐norbornene, 6, and dicyclopentadiene residues, 4, are detected. Based on the results a mechanism for radiation induced crosslinking in EPDM is proposed.

ChemInform Abstract: THE PREPARATION OF TRICYCLO(4.2.1.02,5)NONA‐3,7‐DIENES BY CYCLOADDITIONS ONTO 3,4‐DISUBSTITUTED CYCLOBUTENES. SPECIFICITIES IN THE DIELS‐ALDER REACTION

AbstractAus dem Dien (I) und dem Dienophil (II) entstehen das exo, anti‐Addukt (III) (80% des Reaktionsgemisches) und das endo, anti‐Addukt (IV), das bei höherer Temperatur unter Decarbonylierung in das Bicyclooctadien (V) übergeht.

The preparation of Tricyclo[4,2,1,02,5]nona-3,7-dienes by cycloadditions onto 3,4-disubstituted cyclobutenes. Specificities in the Diels-Alder reaction

The reaction between cis-3,4-dichlorocyclobutene and 2,5-dimethyl-3,4- diphenylcyclopenta-2,4-dienone forms a mixture of exo,anti (28) and endo,anti adducts (27) with the former predominating. At higher temperatures the endo,anti adduct (27) undergoes smooth decarbonylation to form cis-7,8-dicldoro-2,5-dimethyl-3,4-diphenylbicyclo[4,2,0]octa- 2,4-diene. The stereochemistry of each adduct was determined by a combination of spectral (especially p.m.r.) techniques and chemical trans-formations. Intramolecular nucleophilic displacements and electrophilically induced cyclizations have been instrumental in determining stereochemical relationships. Similar cycloadditions involving 1,2,3,4-tetrachloro-5,5-dimethoxycyclopenta-1,3-diene and 1,4-dimethyl-2,3-diphenylcyclopenta-1,3-diene as the diene components and cis-3,4-dichlorocyclobutene or dimethyl tricyclo[4,2,2,02,5]deca- 3,7,9-triene-7,8-dicarboxylate (10) as dienophiles have been studied and the stereoselectivities determined. A combination of steric and secondary orbital effects have been proposed to account for the observed stereospecificities1. A PMO-based treatment is used to account for the perispecificity of (10) and related alicyclic polyenes.

ChemInform Abstract: CHEMISTRY OF OCTACHLOROFULVALENE, DIELS‐ALDER‐REACTIONS

Octachorofulvalene reacted readily as a dienophile with conjugated olefins to afford (2 + 4) mono- and di-adducts, but it reacted as the diene component with norbornadiene; in contrast, decachloro-2,5-dihydrofulvalene and hexachlorofulvene reacted predominantly as dienic partners with cyclopentadiene.

Chemistry of octachlorofulvalene. Diels–Alder reactions

Octachorofulvalene reacted readily as a dienophile with conjugated olefins to afford (2 + 4) mono- and di-adducts, but it reacted as the diene component with norbornadiene; in contrast, decachloro-2,5-dihydrofulvalene and hexachlorofulvene reacted predominantly as dienic partners with cyclopentadiene.

Azonia polycyclic quinones, o‐diazo‐oxides and related products

Abstract4α‐Azoniaanthracene‐5,6‐ and 5,8‐dione salts have been prepared by nitric acid oxidation of their respective diols, and are shown to function as either an electrophilic dienophile or a diene component in Diels‐Alder‐type reactions. Several azonia o‐quinones have been treated with tosylhydrazine in methanol saturated with hydrogen chloride to give unusually stable o‐diazo‐oxides. A four‐step dehydroxylation procedure is detailed for the conversion of .5,6‐dihydroxy‐4α‐azonia‐anthracene salts to new 5‐hydroxy‐4α‐azoniaanthracene salts.

Long-chain bases in the sphingolipids of atherosclerotic human aorta

Long-chain bases were prepared from human aorta sphingomyelin by a combined enzymatic hydrolysis-alkaline hydrolysis procedure and these bases were isolated by thin-layer chromatography. Aldehydes, obtained from the long-chain bases by periodate oxidation, were converted to 1,3-dioxolane derivatives. Dioxolanes were identified and quantified by gas-liquid chromatography before and after catalytic hydrogenation, and before and after separation into saturated, monoene, and diene dioxolane fractions. The monoene dioxolanes were converted to aldehydes by reductive ozonolysis with dimethyl sulfide and these aldehydes were isolated and identified as dioxolane derivatives. The double bond positions in the major diene component were established by reductive ozonolysis and permanganate-periodate oxidation. Sphingenines in the cerebroside-sulfatide and sulfatide fractions of aorta were converted to aldehydes by the reductive ozonolysis of intact sphingolipids and these aldehydes were analyzed as the dioxolanes. Human aorta sphingomyelin contained significant amounts of 4-hexadecasphingenine, 4-heptadecasphingenine, sphinganine, 4-sphingenine, and 4,x14-sphingadienine. Small amounts of hexadecasphinganine, 4-tetradecasphingenine, a sphingadienine isomer, an unknown sphinganine, and two unknown diene long-chain bases were also found in sphingomyelin. The presence of a branched-chain 4-sphingenine was tentatively established and the possible presence of a sphingenine isomer was suggested. The major sphingenines were the same in the sphingomyelin, sulfatide, and cerebroside-sulfatide fractions of human aorta.

含窒素共軛系ジエンに関するDiels-Alder反応 (第1報)

The Diels-Alder reactions reported to date chiefly used C=C-C=C system as the diene component and the use of C=C-C=N or N=C-C=N system was extremely rare. The present series of experiments were carrid out in order to see how far the nitrogen-containing conjugated diene system would submit to this reaction and, becuase, if C=C-C=N system diene synthesis was possible in 1-vinyl-3, 4-dihydroisoquinoline derivatives, it would contribute much to the synthesis of benzoquinolizine compounds, important as the basic structure of numerous alkaloids.The synthesis of 1-vinyl derivative of isoquinoline seemed somewhat difficult that 1-styryl derivative, which can be prepared easily, was chosen. Its reaction with maleic anhydride was carried out and the reduction and decarboxylation of its reaction product afforded 1, 2, 3, 4, 6, 7-hexahydro-9, 10-dimethoxy-2-phenyl-11bH-benzo[α]-quinolizine, whose structure was confirmed by the identity of its infrared absorption spectrum with that of the authentic specimen synthesized by another route. Although the yield of this product is still not satisfactory as yet, it is certain that the desired objective had been attained.

含窒素共軛系ジエンに関するDiels-Alder反応 (第2報)

Following the previous report on the reaction of 1-styryl-3, 4-dihydroisoquinoline derivatives, as diene component of a C=C-C=N system, with maleic anhydride, a reaction of 1-cyclohexenyl-3, 4-dihydro-6, 7-dimethoxyisoquinoline, possessing a cyclohexenyl group in place of styryl, with maleic anhydride was carried out under practically identical conditions. A compound (IV), identical in analytical values with that anticipated, was isolated as its picrate. In order to establish its structure, Hofmann degradation of the methiodide of the substance obtained by reduction and saponification of (IV), was carried out. Repeated three degradations resulted in the liberation of trimethylamine to form a neutral substance. Such a fact confirms the benzoquinolizine structure of the product and thereby indicates that this is a regular reaction. It was concluded from the result of the present and the preceding experiments that the diene component of C=C-C=N system including the C=N bond in 1-2 positions of the 3, 4-dihydroisoquinoline compound can take part in the Diels-Alder type reaction.

The Use of Diarylvinyl Bromides as Diene Components in the Wagner-Jauregg Reaction

The Use of Diarylvinyl Bromides as Diene Components in the Wagner-Jauregg Reaction