Aldehyde Functional Groups Research Articles

Synthesis of a chemically bonded weak cation exchange material by conversion of an allyl phase

The allyl bonded phase is used as an intermediate in the synthesis of a weak cation exchange material. The double bond is first converted to an aldehyde by an ozonation reaction and then subsequent oxidation to the carboxylate group is accomplished with dichromate. Diffuse reflectance Fourier transform infrared spectroscopy (DRIFT) is used to monitor the conversion process. The presence of the aldehyde functional group is confirmed by reaction with 2,4-dinitrophenylhydrazine. ESCA spectra reveal no residual chromium on the silica surface. The product is tested chromatographically by the retention of alkylarylketones, the ion-exchange behavior of both monovalent and divalent cations, the retention of nucleosides and bases, and the separation of a mixture of hemoglobins.

Electron spin resonance and UV absorption of irradiated poly(vinyl alcohol)

AbstractElectron spin resonance (ESR) of γ‐irradiated poly(vinyl alcohol) (PVA) at room temperature has been used to identify the radiation damage products. The ESR spectrum is analyzed by using least‐squares fits between observed and calculated spectra, assuming various free radical species. The best theoretical fit, together with UV absorption data, enabled the assignment of the observed ESR spectrum. The existence of carbonyl macrofree radicals, probably with aldehyde functional groups, is proposed in irradiated PVA.

Introduction of carboxylic acid, aldehyde, and alcohol functional groups onto the surface of poly(chlorotrifluoroethylene)

Introduction of carboxylic acid, aldehyde, and alcohol functional groups onto the surface of poly(chlorotrifluoroethylene)

An electrochemical study of gossypol in methanol

Solutions of gossypol in buffered methanol were studied by polarography, triangular-wave voltammetry, controlled-potential coulometry, and ultraviolet-visible spectrophotometry. The two aldehydic functional groups on gossypol are irreversibly electrochemically reduced to the alcohols. A mechanism is proposed for the reduction.

Electrocatalytic oxidation of saturated oxygenated compounds on gold electrodes

The electrocatalytic oxidation of several saturated oxygenated organic compounds (ethanol, ethylene glycol, acetaldehyde, glycolaldehyde, glyoxal, acetic acid, glycolic acid, glyoxylic acid, oxalic acid, glycerol, and the four butanol isomers) was investigated on gold electrodes both in acid and alkaline medium using cyclic voltammetry. For all the compounds investigated in this work, gold behaves as a poor electrocatalyst in acid medium, except for the oxidation of glyoxylic acid and oxalic acid. In alkaline medium, conversely, gold is an excellent electrocatalyst (even much better than platinum), particularly for the oxidation of the aldehyde functional group and the alcohol group.

Are there Diagnostic Spectral Features of Irradiated Cometary Ices?

There is now evidence that at least some cometary nuclei are dark and red. Cometary ices prepared from combinations of CH4 with H2O and sometimes NH3 were irradiated at 77 K by corona discharge. CH4 - containing ice reddened and darkened at a dose ~1011 erg cm−2 over a period of ~1 hour. Upon evaporation of the now yellowish, irradiated ice, a slightly yellowish colored solid film remains on the walls of the container at room temperature. Transmission measurements of this organic film (called cometary tholin) were made from 0.2 μm to 50 μm wavelength. Strong UV absorption is seen from 0.45 μm to 0.2 μm. Above 0.45 μm, the spectrum remains flat to ~1.3 μm in the near infrared, except for a very small feature near 1.15 μm. A medium sized feature appears centered at 1.4 μm with shoulders at both sides and a nearby weaker feature at 1.52 μm. A strong feature appears at 1.9 μm accompanied by a smaller feature at 1.78 μm. in the region 2.5 μm to 50 μm, the infrared spectrum was taken by dispersing the film in a CsI matrix. Bands are found at 2.92(M), 3.36(S), 3.40(S), 3.46(M), 3.48(M), 5.75(M), 5.99(S), 6.21(M), 6.83(M), 7.30(S), 7.81(W), 8.89(M), 9.26(M), 20.00(W), 22.22(W), and 28.57(W) micrometers, suggesting complex organics including alkane, alkene, aldehyde, and carboxylic acid functional groups. These results are also relevant to UV and cosmic ray processing of interstellar grains, and to icy bodies in the outer solar system.

Antiviral activities of gossypol and its derivatives against herpes simplex virus type II

Gossypol, a disesquiterpene obtained from cottonseed oil, and a series of peri-acylated gossylic nitriles were compared for their antiviral activities against HSV-II and for their toxicities to the host Vero cells. All of the peri-acylated gossylic nitriles exhibited lower cytotoxicities to the host cell than did the parent compound gossypol. Both gossypol and the series of derivatives exhibited antiviral activities against HSV-II when the virus was treated with drug at concentrations as low as 5 × 10 −7 M . Two of the derivatives, gossylic nitrile-1, 1′-diacetate and gossylic nitrile-1, 1′-divalerate, were capable of inhibiting viral multiplication in Vero cells that were infected with virus before administration of the drug. The results of this study indicate that modification of the aldehyde functional groups on gossypol lowers the toxicity of this drug but does not abolish its antiviral properties. Derivatives of gossypol may be useful antiviral agents.

Tropylium tetrafluoroborate, a novel substrate for aldehyde oxidase

The stabilized carbonium ion salt, tropylium tetrafluoroborate, was oxidized to tropone (cycloheptatrienone) by rabbit liver aldehyde oxidase but not by the closely related molybdenum hydroxylase, xanthine oxidase. The tropylium cation is an aromatic hydrocarbon which lacks the aldehyde, imine, or iminium functional groups present in other substrates of aldehyde oxidase. The unique structural features of the tropylium ion should make it a useful tool for mechanistic studies of aldehyde oxidase.

9,11-Dodecadienyl alcohols, acetates, or aldehydes as synthetic chemical sex attractants for four Lepidoptera:Cosmopterix gemmiferella (Clemens),Dichrorampha simulana (Clemens),Tortricidia testacea (Packard), and anAncylis sp.

Four lepidoptera were lured to field traps containing various combinations of 9,11-dodecadienes with alcohol, acetate, or aldehyde functional groups. All species required two chemical components for best attraction.Cosmopterix gemmiferella was most responsive to a combination of (9Z)-9,11-dodecadienyl acetate and (9E)-9,11-dodecadienyl acetate in 2∶1 ratio;Dichrorampha simulana to (9E)-9,11-dodecadienyl acetate and (9E)-9,11-dodecadien-1-ol in 10∶1 ratio;Tortricidia testacea to (9Z)-9,11-dodecadienal and (9E)-9,11-dodecadienal in 10∶1 ratio; andAncylis sp. to (9Z)-9,11-dodecadienyl acetate and (9Z)-9,11-dodecadien-1-ol in 10∶1 ratio.

Chemical transformation of eremofortin C into PR toxin.

The natural products of both eremofortin C (EC) and PR toxin are secondary metabolites of Penicillium roqueforti. Because the chemical structures of EC and PR toxin are closely related to each other and differ only by a hydroxyl functional group in EC and an aldehyde functional group in PR toxin at the C-12 position, the chemical transformation of EC into PR toxin was investigated. Oxidation with a chromic anhydride-pyridine complex was found to be the most satisfactory method.

Modified polystyrenes: Effects of pendant functional groups on thermal stability

Linear polystyrenes modified with pendant chloromethyl, sulfide, sulfoxide, sulfone and aldehyde functional groups have been prepared and their modes of thermal decomposition studied by thermal analysis in a flowing nitrogen atmosphere. Results are interpreted in terms of the effects of functional groups on polymer stability.

Attraction of tortricid moths of subfamily olethreutinae to field traps baited with dodecadienes

All four geometrical isomers of 7,9- and 8,10-dodecadienes with acetate, alcohol, and aldehyde functional groups were synthesized and field tested. The field survey produced sex attractant lures for 14 insect species. Species in the generaCydia, Grapholita, Eucosma, Pelochrista, Petrova, Phenta, Hedya, and Pseudosciaphila were captured. Defined lures were developed for some of the species captured. Gas chromatographie retention times for all geometrical isomers of 7,9- and 8,10-dodecadienes with acetate, alcohol, and aldehyde functional groups are reported. A study of the isomerization of 8,10-dodecadienyl acetates and aldehydes impregnated in rubber septa is reported.

Aldehyde Pheromones in Lepidoptera: Evidence for an Acetate Ester Precursor in Choristoneura fumiferana

Labeling studies of the eastern spruce budworm in vivo indicate that trans-11-tetradecenyl acetate is synthesized specifically in the pheromone-producing gland and is degraded in concert with pheromone release; hence it may be a precursor to the trans-11-tetradecenal pheromone. Radioactivity from exogenously added labeled fatty acids did not appear to be directly incorporated into the ester, suggesting that de novo biosynthesis from acetate is the major route of ester biosynthesis. Conversion of the acetate ester to alcohol and aldehyde functional groups may be the principal method of regulating pheromone specificity between species of Choristoneura.

Ab initio studies of structural features not easily amenable to experiment. 30. Conformational analysis and molecular structures of propanal and butanal

AbstractThe geometries of several conformations of propanal and butanal have been refined by geometrically unconstrained ab initio gradient relaxation on the 4‐21G level. Both compounds possess energy minima at OCCC torsional angles of 0° and in the 120° region, and energy maxima in the 70° region and at 180°. The structure of the aldehyde functional group is found to be relatively invariant both when different systems or when different conformations of the same system are compared. Conformationally dependent geometrical trends in propanal and butanal are discussed and found to be subtle yet noticeable.

Regeneration of rhodopsin and bacteriorhodopsin. The role of retinal analogues as inhibitors.

The rate of regeneration of rhodopsin, from 11-cis-retinal and opsin, and bacteriorhodopsin from all-trans-retinal and bacterio-opsin, in the presence or absence of compounds whose structures partially resemble retinal were measured. Some of these compounds severely slowed down the regeneration process, but did not influence the extent of regeneration. In the case of compounds with a carbonyl functional group they were not joined to the active site of the apo-protein via a Schiff's base linkage since after treatment with NaBH4 an active apo-protein remained. The most effective inhibitors of rhodopsin regeneration were molecules whose structure could be superimposed on 9-cis or 11-cis retinal up to carbon atom 11. These C13 and C15 molecules were not distinguished between aldehyde, ketone or alcohol functional groups. The regeneration of bacteriorhodopsin was not inhibited by retinal analogues with short side chains. The most effective inhibitors were the all-trans C17-aldehyde (beta-ionylideneacetaldehyde) or C18-ketone (beta-ionylidenepent-3-ene-2-one) which, compared to retinal, lack two or three carbon atoms from the end of the poylene chain. The inhibition was very dependent upon the presence of the all-trans isomer and required aldehyde or ketone as functional group nitriles and alcohols were less effective. However, similarly to retinol, the all-trans C17 and C18 alcohols underwent a bathochromic shift and showed fine-structured spectra when mixed with bacterio-opsin.

Photochemical and hot hydrogen atom reactions of acetaldehyde

Photolysis and hot hydrogen atom reactions of acetaldehyde have been studied simultaneously not only with a cadmium but also with a zinc resonance lamp as the light source. Contrary to previous results, new products (acetone, ethanol, 2-propanol, ethyl acetoacetate, and diacetone alcohol) are identified in the photolysis of acetaldehyde. On the other hand, the principal products in decreasing order from the hot atom reaction with acetaldehyde have been established to be hydrogen, biacetyl, methane, carbon monoxide, and ethanol, whereas acetone and ethylene existed as minor products. A study of product quantum yields at 214 nm vs. various (CH/sub 3/CHO)/(CH/sub 2/S) ratios are reported. The formation of several unexpected products in these studies strongly suggested that the aldehyde functional group of acetaldehyde has an unsaturated character relative to the addition of both hydrogen atoms and methyl radicals. This latter new observation and accompanying mechanisms are discussed. 2 figures, 6 tables.

Determination of carbonyl groups in polymers by reaction with 2,4-dinitrophenylhydrazine

The 2,4-dinitrophenylhydrazine (DNPH) analysis of oxygenated functional groups in model polymers has been investigated. Whereas, aldehydic functional groups can be quantitatively analysed by previously reported methods, ketonic groups are only partially detected. Carboxylic, ester and epoxy groups do not significantly interfere in the conventional analytical methods. The reactivity of polymeric carbonyl groups towards DNPH appears to be markedly affected by steric factors, determined by the polymeric microstructure. The applicability of the DNPH method to the analysis of oxygenated functional groups in natural rubber and oxidized poly(ethylene) is discussed.

The synergistic binding of anions and Fe3+ by transferrin. Implications for the interlocking sites hypothesis.

The finding that transferrin does not bind Fe3+ at the specific metal binding sites in the absence of carbonate and synergistic anions emphasizes the fundamental importance of the anion binding site to the chemistry of Fe3+-transferrin-CO32-. An important question regards the chemical and structural requirements for carbonate substitution. This has been, however, an area of some dispute in the literature. We have utilized four synthetic routes for the preparation of Fe3+-transferrin-anion complexes. The products have been examined with regard to spectral properties, and reaction with: (a) NaHCO3, (b) Fe3+-nitrilotriacetic acid in NaHCO3, and (c) sodium citrate under CO2-free conditions. The results provide information as to which anions are synergistic, and the basic properties of the Fe3+-transferrin-anion complexes that are formed. The 6 inorganic anions that were tested were all found to be nonsynergistic. Dihydroxyacetone and glyceraldehyde were also nonsynergistic. Dicarboxylic acids were found to form stable Fe3+-transferrin-anion complexes which were only slowly displaced by carbonate. Several monocarboxylic acids with proximal aldehyde, ketone, alcohol, amino, or thiol functional groups proved to be synergistic. CPK molecular model studies suggested the functional group and the carboxylic acid must be able to fit within a site between 6.3 and 7.0 A in maximal length. One large substituent could be accommodated by the site, however, two methylgroups on the alpha carbon to a carboxylate group could not be accommodated. Chloroacetate and monocarboxylic acids were nonsynergistic. The results are interpreted in terms of an interlocking sites hypothesis which envisions the synergistic anion as interacting with the protein via its its carboxyl group and bonding with the Fe3+ via its proximal functional group.

Fluorescent chromophore components from the egg capsules of the gastropod mollusc Buccinum undatum (L.), and their relation to fluorescent compounds in other structural proteins

1.1. The egg capsules from the gastropod mollusc Buccinum undatum contain a yellow fluorophore with aldehydic functional groups.2.2. The fluorophore-chromophore was partially purified by gel-filtration and ion-exchange chromatography.3.3. Partial hydrolysis and electron microscopic examination suggest that the egg capsules contain a resistant cross-linked core.4.4. There is evidence for the association of the fluorophore with the cross-linked core of the protein.5.5. Comparison is made between the fluorophore and fluorescent moieties found in other structural proteins.

A collagen defect in homocystinuria.

The biochemical mechanism accounting for the connective tissue abnormalities in homocystinuria was explored by examining the effects of various amino acids known to accumulate in the plasma of patients with this disease on cross-link formation in collagen. Neutral salt solutions of purified, rat skin collagen, rich in cross-link precursor aldehydes, were polymerized to native type fibrils by incubating at 37 degrees C in the presence of homocysteine, homocystine, or methionine. After the polymerization was completed, each sample was examined for the formation of covalent intermolecular cross-links, assessed indirectly by solubility tests and directly by measuring the cross-link compounds after reduction with tritiated sodium borohydride and hydrolysis. Collagen solutions containing homocysteine (0.01 M-0.1 M) failed to form insoluble fibrils. Furthermore, much less of the reducible cross-links, Delta(6,7) dehydrohydroxylysinonorleucine, Delta(6,7) dehydrohydroxylysinohydroxynorleucine, and histidino-dehydrohydroxymerodesmosine were formed in the preparations containing homocysteine as compared with the control and the samples containing methionine or homocystine. The content of the precursor aldehydes, alpha-aminoadipic-delta-semialdehyde (allysine) and the aldol condensation product, was also markedly diminished in tropocollagen incubated with homocysteine. It is concluded that homocysteine interferes with the formation of intermolecular cross-links that help stabilize the collagen macromolecular network via its reversible binding to the aldehydic functional groups. Analysis of the collagen cross-links in skin biopsy samples obtained from three patients with documented homocystinuria showed that the cross-links were significantly decreased as compared with the age-matched controls, supporting the tentative conclusions reached from the in vitro model studies. In addition, the solubility of dermal collagen in non-denaturing solvents was significantly increased in the two patients examined, reflecting a functional defect in collagen cross-linking. Although the concentration of homocysteine used in this study to demonstrate these effects in vitro is clearly higher than that which is observed in homocystinuric's plasma, the data do suggest a possible pathogenetic mechanism of connective tissue defect in homocystinuria.