Carbonyl secondary production

The simple procedure for the carbonylation of allyl halides has been extended in the high yielding solid-liquid two-phase conversion of allyl phosphates into amides (60-80%) under the influence of a rhodium carbonyl cluster in the presence of primary or secondary amines (Scheme 8.8). A secondary product of the reaction is the allylamine, the concentration of which increases as the pressure of the carbon monoxide is reduced, such that it is the sole product (ca. 80%) in the absence of carbon monoxide [28],... 

It is interesting to note that such pyrone complexes have also been isolated from the carbonylation of products obtained from the reaction of 184.a with a secondary amine.126 Park invokes two vinylketene complexes (201 and 202) as key intermediates in the transformation, although none... 

Other indices measure a secondary stage of oxidation, such as the anisidine value (ANV), pointing to formation of carbonyl compounds, capable of undergoing condensation reactions with p-anisidine, and the thiobarbituric acid reactive substance (TBARS) pointing to the presence of malondialdehyde (MDA) in particular. In biological systems, TBARS is of widespread use as a measure for the extent of oxidation damage. Another test for stability of oils to oxidation is based on the development of acidity as secondary product, for example, standards using the Rancimat equipment or a similar setup. 

Since nicotine is the major precursor to NNN in tobacco and tobacco smoke, the reaction of nicotine with sodium nitrite was studied to provide information on formation of other tobacco specific nitrosamines, especially NNK and NNA, which could arise by oxidative cleavage of the l -2 bonds or l -5 bond of nicotine followed by nitrosation (26). The reaction was investigated under a variety of conditions as summarized in Table I. All three nitrosamines were formed when the reaction was done under relatively mild conditions (17 hrs, 20 ). The yields are typical of the formation of nitrosamines from tertiary amines (27). At 90 , with a five fold excess of nitrite, only NNN and NNK were detected. Under these conditions, both NNK and NNA gave secondary products. NNK was nitrosated a to the carbonyl to yield 4-(N-methyl-N-nitrosamino)-2-oximino-l-(3-pyridyl)-1-butanone while NNA underwent cyclization followed by oxidation, decarboxylation and dehydration to give l-methyl-5-(3-pyridyl)pyrazole, as shown in Figure 4. Extensive fragmentation and oxidation of the pyrrolidine ring was also observed under these conditions. The products of the reaction of nicotine and nitrite at 90 are summarized in Table II. 

Carbonylation of the urea 27 in the presence of Pd(0) and KOAc as base is a useful route to 4-butyl-2-phenyl-23,44-tetrahydro-l/f-2,4-benzodiazepine-13-dione (28) <99TL2623>. Also isolated from this reaction as secondary product is IV-n-butylisoindoline. Pyrolysis of the cyclobutenones 29 afford the diazepines 30 in moderate yield <99JOC707>. 

Hydroperoxide formation is characteristic of alkenes possessing tertiary allylic hydrogen. Allylic rearrangement resulting in the formation of isomeric products is common. Secondary products (alcohols, carbonyl compounds, carboxylic acids) may arise from the decomposition of alkenyl hydroperoxide at higher temperature. 

In addition to the previously mentioned chemical tests, methods based on the carbonyl content of oxidized fats have also been suggested (Henick et al 1954 Lillard and Day 1961) as a measure of oxidative deterioration. The procedures determine the secondary products of autoxidation and have been reported to correlate significantly with the degree of off-flavor in butter oil (Lillard and Day 1961). The methods, however, are cumbersome and are not suited for routine analysis. 

ALDOL CONDENSATION. A reaction between aldehydes or aldehydes and ketones that occurs without the elimination of any secondary product and yields ) -hydroxy carbonyl compounds. It is distinguished from... 

The major cause of deterioration of food products is lipid oxidation, from which low-molecular-weight, off-flavor compounds are formed. This deterioration is often caused by the oxidation of the unsaturated lipids present in foods. Off-flavor compounds are created when the hydroperoxides, formed during the initial oxidation, are degraded into secondary reaction compounds. Free radicals are also formed which can participate in reactions with secondary products and with proteins. Interactions with the latter can result in carbonyl amino... 

Support for the proposal of M+ insertion into the carbon-halogen bond came from later work in which the reactivity of the Fe(CO) + ions (n = 0 - 5) towards allyl chloride was investigated using a MS/MS/MS multiquadrupole spectrometer60. Thus, while with the naked Fe+ the only observed products were FeCl+ (minor) and C3H5+ (and the secondary products derived from its reaction with neutral allyl chloride), with the iron carbonyl... 

Peroxynitrite, like other oxidants, reacts with proteins, first oxidizing cysteine methionine and tryptophan residues (A7). The reaction products are sulfones, carbonyl moieties, and dityrosines (K23, M29). Formation of protein hydroperoxides and protein fragmentation was also observed (B7, G6). Nitric oxide induces oxidation of methionine residues, thus effecting oxidative damage to proteins (Cl 1). It also reacts with Fe-S clusters of aconitase (D15), though in most cases it is difficult to assess whether these effects are produced by the NO itself, or rather by a more reactive secondary product such as peroxynitrite (C5). At physiological... 

Chromium trioxide, OO3 Oxidizes alcohols in aqueous acid to yield carbonyl-containing products. Primary alcohols yield carboxylic acids, and secondary alcohols yield ketones (Sections 17.7 and 19.3). 

Formation of Secondary Products and Lipohydroperoxide Destruction. As early as 1945 Holman and Burr (132) found that crude soybean lipoxygenase acting on a number of substrates produced carbonyl-containing material in addition to diene. Holman, as noted above (107), used his crystalline enzyme and found that it was difficult to establish a correspondence between O2 consumption and diene conjugation. The diene concentration always tended to be too low. Privett et al. 123) found that the reaction products varied with enzyme concentration and method of addition. Vioque and Holman 133) identified 9-keto-ll,13- and 13-keto-9,ll-octadecadienoate with the usual hydroperoxides in a reaction carried out with linoleic acid and a relatively large amount of crude soybean lipoxygenase at pH 9. 

Because of the presence of the carbonyl group in the molecule, they react with sodium bisulphite to form well-crystallised additive products. This behaviour is employed in practice to separate the halogenated ketones from the secondary products of the reaction. 

An acyl group can be introduced into the 4 position of an a,(3-unsamrated ketone by treatment with an organolithium compound and nickel carbonyl. The product is a 1,4-diketone, 157. The R group may be aryl or primary alkyl. The reaction can also be applied to alkynes (which need not be activated), in which case 2 mol add and the product is also a 1,4-diketone (e.g., R C=CH RCOCHR CH2COR). " In a different procedure, ot,(3-unsaturated ketones and aldehydes are acylated by treatment at — 110°C with R2(CN)CuLi2 and CO. This method is successful for R = primary, secondary, and tertiary alkyl.For secondary and tertiary groups, R(CN)CuLi (which does not waste an R group) can be used instead. 

Alkenes can be hydroformylated " by treatment with carbon monoxide and hydrogen over a catalyst. The most common catalysts are cobalt carbonyls (see below for a description of the mechanism) and rhodium complexes, " but other transition metal compounds have also been used. Cobalt catalysts are less active than the rhodium type, and catalysts of other metals are generally less active. " Commercially, this is called the 0x0 process, but it can be carried out in the laboratory in an ordinary hydrogenation apparatus. The order of reactivity is straight-chain terminal alkenes > straight-chain internal alkenes > branched-chain alkenes. With terminal alkenes, for example, the aldehyde unit is formed on both the primary and secondary carbon, but proper choice of catalyst and additive leads to selectivity for the secondary product " or primary... 

The liquid phase photolysis of several alcohols was first systematically studied in the years between 1910 and 1913 by Berthelot and Gaudechon using a medium pressure mercury arc (21). They recognized that the main photolysis products of primary and secondary alcohols were H2 and an equivalent amount of aldehyde and ketone, respectively (21a,b). They also found (21d) that the part of the ultraviolet spectrum active on alcohols must lie below 250 nm, while carbonyl compounds are readily decomposed by light around 250 nm and above, yielding much CO. It was concluded (21d,22) that CO was a secondary product of the alcohol photolyses and due to the photolysis of the primarily produced carbonyl compound. In aqueous solutions of the alcohols the rate of decomposition was lower (21d) but led to the same products as those found in the neat photolyses. Similar to the liquid phase results Bates and Taylor (1927) found H2 as the major product in the methanol and ethanol gas phase photolysis (23). 

Using this pulse sequence to estimate the nature of derivatization of Suwannee River fulvic acid with N-enriched hydroxylamine to leam more about the carbonyl functionality of fulvic acid, Thom et al.(76) obtained signals for the primary products as oximes. Additional signals of secondary products arising from Beckmann rearrangements of the initial oxime derivatives were identified as nitriles, secondary amides and lactams. The bands assigned to hydroxamic acid result from a reaction of esters with NH2OH and are evidence for the presence of esters in the fulvic acid. 

There are, however, numerous organic precendents. The Cannizzaro reaction, in which two equivalents of a nonenolizable aldehyde such as bezaldehyde are reacted with hydroxide to form a primary alcohol and the salt of a carboxylic acid, is thought to involve hydride transfer to one aldehyde carbonyl from the carbonyl-addition product of the other aldehyde and hydroxide. The Leuckart reaction, formation of a tertiary amine from formic acid, a primary amine and either a ketone or an aldehyde, seems to procede via hydride transfer from formate to an iminium ion. And the Meervein-Ponndorf-Verley-Oppenauer reaction, the reversible transfer of hydrogen between ketones and secondary alcohols in the presence of excess aluminum isopropoxide, is almost certainly a hydride-transfer reaction. This latter process is of particular interest to us because it requires a metal, just as GI does. The aluminum acts as a Lewis acid, coordinating the carbonyl oxygen and... 

As with polystyrene sulfonic resins, Nafion-based acid catalysts are highly efficient for hydration and dehydration processes and, in general, for condensation reactions that occur with the formation of water or similar secondary products. Formation of ethers has been studied for various alcohols [109-111]. Dehydration of 1,4- and 1,5-diols at 135 °C affords the corresponding cyclic ethers such as 20 in excellent yields (Scheme 10.7), while 1,3-diols experience different transformations depending on their structure [112]. The dehydration of 1,2-diols mainly proceeds via the pinacol rearrangement. Further condensation of the initially formed carbonyl compound and unreacted diol affords 1,3-dioxolanes [113]. The catalyst could be efficiently reused following a reactivation protocol. Formation of aryl ethers is also possible, and the synthesis of dibenzofurans 21 (X = O) from 2,2 -dihydroxybiphenyls has been reported (Scheme 10.7) [114]. The related reaction... 

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