Aldehydes toxicity

Toropov AA, Benfenati E (2004) QSAR modelling of aldehyde toxicity against a protozoan, Tetrahymena pyriformis by optimization of correlation weights of nearest neighboring codes. J. Mol. Struct. (Theochem) 679 225-228. 

Heck H Mechanisms of aldehyde toxicity Structure activity studies. CUT Activities 5(10) 106, 1985... 

Sprince H, Parker CM, Smith GG. 1978. Ascorbic-acid and cystein protection against aldehyde toxicants of cigaret smoke. Fed Proc 37 247. 

But beware for ethanol at levels elevated In liver cells, in cytosol, is dehydrogenated NADH to NAD the ratio s distorted There s aldehyde toxicity (as recently reported ). 

Paraldehyde is metabolized in the liver to acetaldehyde (22), and the metabohsm of aldehyde by aldehyde dehydrogenase is inhibited by disulfiram, causing aldehyde toxicity. The adverse effects of this have been shown in experimental animals (23) and there have been reports of confusional psychosis in patients given disulfiram and paraldehyde (24). 

Oil of Qyeput. Cajuput oil cajeputi oil. Volatile od from fresh leaves and twigs of several varieties of Melaleuca Ieucadendron L, and other species of Melaleuca, Myrtaceae. Constit 50-60% eucalyptol (cineol) (-pinene, terpineol valeric, butyric, benzoic and other aldehydes. Toxicity P. M. Jenner et (., Food Cosmet Toxicol. 2, 327 (1964). 

NATURAL GAS. compressed with high 1988 28 ALDEHYDES, toxic, n.o.s. 

Interest ia the toxicity of aldehydes has focused primarily on specific compounds, particularly formaldehyde, acetaldehyde, and acroleia (13). Litde evidence exists to suggest that occupational levels of exposure to aldehydes would result ia mutations, although some aldehydes are clearly mutagenic ia some test systems. There are, however, acute effects of aldehydes. 

There is a significant difference in the toxicological effects of saturated and unsaturated afiphatic aldehydes. As can be seen in Table 6, the presence of the double bond considerably enhances toxicity. The precautions for handling reactive unsaturated aldehydes such as acrolein, methacrolein [78-85-3] and crotonaldehyde should be the same as those for handling other highly active eye and pulmonary irritants, as, for example, phosgene. 

Reactions. Heating an aqueous solution of malonic acid above 70°C results in its decomposition to acetic acid and carbon dioxide. Malonic acid is a useful tool for synthesizing a-unsaturated carboxyUc acids because of its abiUty to undergo decarboxylation and condensation with aldehydes or ketones at the methylene group. Cinnamic acids are formed from the reaction of malonic acid and benzaldehyde derivatives (1). If aUphatic aldehydes are used acryhc acids result (2). Similarly this facile decarboxylation combined with the condensation with an activated double bond yields a-substituted acetic acid derivatives. For example, 4-thiazohdine acetic acids (2) are readily prepared from 2,5-dihydro-l,3-thiazoles (3). A further feature of malonic acid is that it does not form an anhydride when heated with phosphorous pentoxide [1314-56-3] but rather carbon suboxide [504-64-3] [0=C=C=0], a toxic gas that reacts with water to reform malonic acid. 

In addition to natural muscarine and the so-called choline-muscarine referred to above, two other products have been given names suggesting relationship to muscarine, viz. (1) isomuscarine, Me3N(OH). CHOH. CH2OH prepared by Bode and shown to be toxic, but distinct from muscarine in type of action, and (2) anhydromuscarine (betaine aldehyde) made first by Berlinerblau and later by Fischer and which, according to Voet possesses nicotine and curare-like properties. 

On the other hand, the corresponding tin precursor (63) undergoes smooth cycloaddition with a wide variety of aldehydes to produce the desired methylene-tetrahydrofnran in good yields [32, 33]. Thus prenylaldehyde reacts with (63) to give cleanly the cycloadduct (64), whereas the reaction with the silyl precursor (1) yields only decomposition products (Scheme 2.20) [31]. This smooth cycloaddition is attributed to the improved reactivity of the stannyl ether (65) towards the 7t-allyl ligand. Although the reactions of (63) with aldehydes are quite robust, the use of a tin reagent as precursor for TMM presents drawbacks such as cost, stability, toxicity, and difficult purification of products. 

The Schmidt reaction of ketones works best with aliphatic and alicyclic ketones alkyl aryl ketones and diaryl ketones are considerably less reactive. The reaction is only seldom applied to aldehydes as starting materials. The hydrazoic acid used as reagent is usually prepared in situ by treatment of sodium azide with sulfuric acid. Hydrazoic acid is highly toxic, and can detonate upon contact with hot laboratory equipment. 

The scope of the reaction depends on the availability of the starting aldehyde (or ketone). A drawback is the toxicity of the hydrogen cyanide used as reactant. ... 

Further oxidation of an aldehyde product to the corresponding carboxylic acid does not take place. Moreover, the SM>ern oxidation reaction does not require the use of toxic and pollutant chromium reagents. The activated DMSO species, however, are stable only at low temperature, which might in some cases be a drawback of this method. 

Osmium tetroxide, reaction with alkenes, 235-236 toxicity of, 235 Oxalic add, structure of, 753 Oxaloacetic acid, structure of, 753 Oxetane, reaction with Grignard reagents, 680 Oxidation, 233, 348 alcohols, 623-626 aldehydes, 700-701 aldoses, 992-994 alkenes, 233-236 biological, 625-626 phenols, 631 sulfides, 670 thiols, 668... 

Essential oils are known to have detrimental effects on plants. The inhibitory components have not been identified, but both alde-hydic (benzol-, citrol-, cinnamal-aldehyde) and phenolic (thymol, carvacol, apiol, safrol) constituents are suspected. Muller et al. (104) demonstrated that volatile toxic materials localized in the leaves of Salvia leucophylla, Salvia apiana, and Arthemisia californica inhibited the root growth of cucumber and oat seedlings. They speculated that in the field, toxic substances from the leaves of these plants might be deposited in dew droplets on adjacent annual plants. In a subsequent paper, Muller and Muller (105) reported that the leaves of S. leucophylla contained several volatile terpenes, and growth inhibition was attributed to camphor and cineole. 

Miscellaneous Identified Inhibitors. 3-Acetyl-6-methoxy-benzaldehyde is present in the leaves of the desert shrub Encelia farinosa. It is apparently leached from the leaves and washed into the soil by rain. Concentrations of approximately 0.5 mg. per gram of dried leaf material have been measured. In sand culture studies, growth of tomato seedlings was inhibited by 50 p.p.m. while 115 p.p.m. reduced growth by 50% (53). A concentration of 250 p.p.m. killed the test plants within one day. The structure was confirmed by synthesis, and the synthetic material was shown to be as active as the natural product (54). Derivatives were also prepared in which a cyano, nitro, or amino group was substituted for the aldehyde moiety. The amino derivative was reported to be the most highly toxic. 

The most successful class of active ingredient for both oxidation and reduction is that of the noble metals silver, gold, ruthenium, rhodium, palladium, osmium, iridium, and platinum. Platinum and palladium readily oxidize carbon monoxide, all the hydrocarbons except methane, and the partially oxygenated organic compounds such as aldehydes and alcohols. Under reducing conditions, platinum can convert NO to N2 and to NH3. Platinum and palladium are used in small quantities as promoters for less active base metal oxide catalysts. Platinum is also a candidate for simultaneous oxidation and reduction when the oxidant/re-ductant ratio is within 1% of stoichiometry. The other four elements of the platinum family are in short supply. Ruthenium produces the least NH3 concentration in NO reduction in comparison with other catalysts, but it forms volatile toxic oxides. 

Ethanol is almost entirely metabolized in the liver. The first step, oxidation by alcohol dehydrogenase, yields acetaldehyde, a reactive and toxic compound. Essentially all of the acetaldehyde is converted to acetate by the liver enzyme aldehyde dehydrogenase. Aldehyde dehydrogenase is inhibited by the drag disulfiram. Given alone, disulfiram is a nontoxic substance. However, ethanol consumption in the presence of... 

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