Acetates decarboxylation

Zehnder, A. J. B., B. A. Huser, T. D. Brock and K. Wuhrmann, 1980, Characterization of an acetate decarboxylating, non-hydrogen-utilizing methane bacterium. Archives of Microbiology 124, 1-11. 

Thus, methyl (5-acetyl-2-thienyIthio)acetate (62) was prepared by acetylation of 61. Addition of a second acetyl group in the presence of excess AlClj led to methyl (3,5-diacetyl-2-thienylthio)acetate (63), which, on heating in ethanolic sodium ethoxide yielded about 95% of 5-acetyl-3-methylthieno[2,3-6]thiophene-2-carboxylic acid (64) reduction of acid 64 resulted in 5-ethyl-3-methylthieno[2,3-6] ophene 2-carboxylic add (65), identical with the acid obtained by cyclization of methyl (3-acetyl-5-ethyl-2-thienylthio)acetate. Decarboxylation of acid 64 gave 5-acetyl-3-methylthieno[2,3-6]thiophene (66) [Eq. (25)1. 

A new method for the degradation of the typical iso-octenyl side-chain of tetracyclic triterpenoids has been reported. The key step involves N-lithioethylene-diamine-induced double-bond isomerizations of the olefin (50), obtained by lead tetra-acetate decarboxylation of the trisnoracid (51), to a mixture of (52) and (53). The details of the n.m.r. spectra of 45 cycloartane derivatives have been described and assignments made for the methyl group signals. "... 

The Chemistry of Rli a.— Two routes have been explored to yield ring a olefins. Nitrous acid deamination of 18-norabieta-8,ll,13-triene-4-amine or the corresponding amine in the 12-methoxypodocarpa-8,ll,13-triene series affords a mixture of A - and A -olefins and a 4-acetate derived from a C-4 car-bonium ion. A similar mixture is obtained from the lead tetra-acetate decarboxylation of dehydroabietic acid and 12-methoxypodocarpic acid. In the... 

The mixture of olefins obtained by lead tetra-acetate decarboxylation of 4-epidehydroabietic acid is very nearly the same as from dehydroabietic acid. Isomerization of these 19-nor-tetra-enes led to some products with a cis a/b ring... 

Acetic anhydride/sodium acetate Decarboxylative ring closure Naphthofurans s. 13,901... 

Schleusener JL, Drummond SE, Palmer DA, Barnes HL (1987) Effects of common minerals on acetate decarboxylation kinetics. Geol Soc Am Abstr Programs 19 832-833... 

Further experiments on the importance of acetate on the dissolution of quartz and Pb-rich K-feldspar have been conducted by Manning et al. (1991) at 150°C, 500 bar and pH values from 5.9 to 9.4. During these experiments, it was discovered that in the presence of quartz plus orthoclase feldspar that acetate decarboxylation occurred at a much higher rate than had been expected. These authors concluded that This study provides little support for models which call upon acetate to enhance the solubility of aluminosilicate minerals.. . . 

A large variety of organic oxidations, reductions, and rearrangements show photocatalysis at interfaces, usually of a semiconductor. The subject has been reviewed [326,327] some specific examples are the photo-Kolbe reaction (decarboxylation of acetic acid) using Pt supported on anatase [328], the pho-... 

When cinnamaldehyde, succinic acid and acetic anhydride are heated in the presence of litharge (PbO), the aldehyde and the succinic acid condense to give the dicarboxylic acid (I), which undergoes decarboxylation to give the pale yellow crystalline 1,8-diphenyloctatetrene (II), Kuhn has shown that as the... 

The addition of active methylene compounds (ethyl malonate, ethyl aoeto-acetate, ethyl plienylacetate, nltromethane, acrylonitrile, etc.) to the aP-double bond of a conjugated unsaturated ketone, ester or nitrile In the presence of a basic catalyst (sodium ethoxide, piperidine, diethylamiiie, etc.) is known as the Michael reaction or Michael addition. The reaction may be illustrated by the addition of ethyl malonate to ethyl fumarate in the presence of sodium ethoxide hydrolysis and decarboxylation of the addendum (ethyl propane-1 1 2 3-tetracarboxylate) yields trlcarballylic acid ... 

A simple application of the reaction may bo mentioned. Refluxing of (I) with 48 per cent, hydrobromic aeid and glacial acetic acid leads to hydrolysis and decarboxylation and the production of a mixture of the yl tctone yr-di-phonylbutyrolaotone (II) and the isomeric unsaturated acid yY-dlphenyl-vinylacotic acid (III) reduction by the Clemmonsen method or catalytically... 

Wylation under neutral conditions. Reactions which proceed under neutral conditions are highly desirable, Allylation with allylic acetates and phosphates is carried out under basic conditions. Almost no reaction of these allylic Compounds takes place in the absence of bases. The useful allylation under neutral conditions is possible with some allylic compounds. Among them, allylic carbonates 218 are the most reactive and their reactions proceed under neutral conditions[13,14,134], In the mechanism shown, the oxidative addition of the allyl carbonates 218 is followed by decarboxylation as an irreversible process to afford the 7r-allylpalladium alkoxide 219. and the generated alkoxide is sufficiently basic to pick up a proton from active methylene compounds, yielding 220. This in situ formation of the alkoxide. which is a... 

Geranyl acetoacetate (685) is converted into geranylacetone (686). On the other hand, a mixture of E- and Z-isomers of 688 is obtained from neryl acetoacetate (687). The decarboxylation and allylation of the allyl malonate or cyanoacetate 689 affords the o-allylated acetate or nitriie[447]. The trifluoromethyl ketone 691 is prepared from cinnamyl 4.4,4-trifluoroacetoace-tate (690)[448],... 

The decarboxylation of allyl /3-keto carboxylates generates 7r-allylpalladium enolates. Aldol condensation and Michael addition are typical reactions for metal enolates. Actually Pd enolates undergo intramolecular aldol condensation and Michael addition. When an aldehyde group is present in the allyl fi-keto ester 738, intramolecular aldol condensation takes place yielding the cyclic aldol 739 as a main product[463]. At the same time, the diketone 740 is formed as a minor product by /3-eIimination. This is Pd-catalyzed aldol condensation under neutral conditions. The reaction proceeds even in the presence of water, showing that the Pd enolate is not decomposed with water. The spiro-aldol 742 is obtained from 741. Allyl acetates with other EWGs such as allyl malonate, cyanoacetate 743, and sulfonylacetate undergo similar aldol-type cycliza-tions[464]. 

Pyrano[3,4-b]indol-3-ones are the most useful equivalents of the indol-2,3-quinodimethane synthon which are currently available for synthetic application. These compounds can be synthesized readily from indole-3-acetic acids and carboxylic anhydrides[5,6]. On heating with electrophilic alkenes or alkynes, adducts are formed which undergo decarboxylation to 1,2-dihydro-carbazoles or carbazoles, respectively. 

Compounds that readily undergo thermal decarboxylation include those related to malonic acid On being heated above its melting point malonic acid is converted to acetic acid and carbon dioxide... 

In keeping with its biogenetic origin m three molecules of acetic acid mevalonic acid has six carbon atoms The conversion of mevalonate to isopentenyl pyrophosphate involves loss of the extra carbon as carbon dioxide First the alcohol hydroxyl groups of mevalonate are converted to phosphate ester functions—they are enzymatically phosphorylated with introduction of a simple phosphate at the tertiary site and a pyrophosphate at the primary site Decarboxylation m concert with loss of the terti ary phosphate introduces a carbon-carbon double bond and gives isopentenyl pyrophos phate the fundamental building block for formation of isoprenoid natural products... 

Maleic anhydride is decomposed in the Hquid phase by various nitrogen bases. Treatment of maleic anhydride in refluxing acetic acid with 2-anainopyridine [504-29-0] gives, after work-up in 4 at 100°C, the decarboxylative dimeri2ation product, 2,3-dimethylmaleic anhydride [766-39-2]... 

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. 

Fig. 2. Synthesis of uma2enil (18). The isonitrosoacetanihde is synthesized from 4-f1iioroani1ine. Cyclization using sulfuric acid is followed by oxidization using peracetic acid to the isatoic anhydride. Reaction of sarcosine in DMF and acetic acid leads to the benzodiazepine-2,5-dione. Deprotonation, phosphorylation, and subsequent reaction with diethyl malonate leads to the diester. After selective hydrolysis and decarboxylation the resulting monoester is nitrosated and catalyticaHy hydrogenated to the aminoester. Introduction of the final carbon atom is accompHshed by reaction of triethyl orthoformate to...

Alkyl Isoquinolines. Coal tar contains small amounts of l-methylisoquinoline [1721-93-3] 3-methylisoquinoline [1125-80-0] and 1,3-dimetliylisoquinoline [1721-94-4J. The 1- and 3-methyl groups are more reactive than others in the isoquinoline nucleus and readily oxidize with selenium dioxide to form the corresponding isoquinoline aldehydes (174). These compounds can also be obtained by the hydrolysis of the dihalomethyl group. The 1- and 3-methyhsoquinolines condense with benzaldehyde in the presence of zinc chloride or acetic anhydride to produce 1- and 3-styryhsoquinolines. Radicals formed by decarboxylation of carboxyUc acids react to produce 1-aIkyhsoquinolines. 

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