Mercury acetate ketones

At the same time, the hydration of 3(5)-phenyl-5(3)-phenylethynylpyrazole 45 in sulfuric acid in the presence of mercury acetate leads to the formation of two isomeric ketones 46 (yield 44%) and 47 (yield 3%) (68LA117) (Scheme 88). 

Singular examples to form aromatic ethers are a base-catalyzed, multistep, one-pot reaction of aryl methyl ketones with the appropriate fluorinated arylidenemalonitriles, the mercury acetate assisted synthesis of pentahalophenylvinyl ethers from vinyl acetate and the corresponding phenol, and the radical displacements in aryloxycyclohexadienones (e.g., 27) by halophenols. 2,3-Dichloro-5,6-dicyanohydroquinone (28) and products such as 29 are readily formed when cyclohexadienone 27 is treated with different phenols. 

Ethoxyacetylene adds, catalyzed by mercury acetate and ZnCh, alii atic or aromatic alcohols to produce mixed substituted orthoesters, e.g. (391)-(393) (Scheme 72). ° Acyl ketenes are formed on thermolysis of l,3-dioxin-4-ones, which can be trapped with ketene acetals to give orthoesters (394 equation 181) 861-863 2,2-Dialkoxydihydrofurans (395 equation 182) are accessible by addition of ketones to cy-clopropenone acetals. Treatment of 2-chloro-2,3-dimethoxy-l,4-dioxane with sodium methoxide affords the 2,2,3-trimethoxy-l,4-dioxane (396 equation 183). ... 

If mercury chloride is added to an aqueous solution of the 2-methyl-3-butyn-2-ol a white mercury derivative is precipitated, and if this is boiled with hydrochloric acid it gives the same 3-hydroxy-3-methyl-2-butanone as mentioned above.97 With mercury acetate in glacial acetic acid at 75-95° the alkynol gives a 98.5% yield of the acetoxy ketone.98... 

Hydrocarbon A has the formula C9HI2 and absorbs 3 equivalents of H to yield B, C9H]g, when hydrogenated over a Pd/C catalyst. On treatment of A with aqueous H2S04 in the presence of mercury(d), two isomeric ketones, C and D, are produced. Oxidation of A with KMn04 gives a mixture of acetic acid (CH3C02H) and the tricarboxylic acid E. Propose structures for compounds A-D, and write the reactions. 

Reduction of 2-bromo-3-pentanone at mercury affords a mixture of 3-pentanone and l-hydroxy-3-pentanone, whereas electrolysis of Q ,Q -dibromoacetone in the presence of benzoate gives a mixture of products arising from both a carbon-bromine bond cleavage and an Sn2 displacement of bromide by benzoate [94]. In an acetic acid-acetate buffer, branched dibromo ketones, such as 2,4-dibromo-2,4-dimethyl-3-pentanone, are reduced to a-acetoxy ketones however, less highly substituted compounds, such as 4,6-dibromo-5-nonanone, undergo simple cleavage of both carbon-bromine bonds [95]. Other work dealing with the reduction of Q, Q -dibromoketones has been described [96]. 

Mesityl oxide at a mercury cathode in acetate buffer affords a mixture of tail-to-tail and head-to-tail hydrodimers. The initally formed reduction products undergo further reactions so that 32 and 33 are isolated [106, 107, 108]. A low yield of the head-to-head glycol has been isolated from some reactions [109, 110, 111]. The structures of these products were confirmed in 1955 [112], Methyl vinyl ketone yields a mixture of tail-to-tail and head-to-head hydrodimers [113],... 

Enol ethers and acetals are formed when alcohols add to alkynes. The reaction of alcohols may be catalyzed by mercury(II) salts 43,44 Hg(OAc)2 with or without TosOH allows the synthesis of enol ethers, acetals, or ketones under appropriate reaction conditions.44 Au3+ was found to be an effective catalyst in the synthesis of acetals 37... 

Thiophenecarbaldehydes add smoothly to a,f3-unsaturated ketones and nitriles under cyanide ion catalysis to form y-diketones (366) and y-ketonitriles (367) respectively (76CB534). The 2,5-dicarbaldehyde gives the bis-adduct (368). The aldehydes undergo normal reduction to the hydroxymethylthiophenes by sodium borohydride. However, electrochemical reduction of the 2,5-dialdehyde on a mercury electrode at pH 1-3 gives the bimolecular reduction product (369) as a mixture of meso- and ( )-forms in the ratio 7 3. Reduction with zinc and acetic acid gives only the meso -form of (369) (75CR(C)(280)165>. 

Acetals are usually easy to cleave by acid-catalyzed transacetalization or hydrolysis (Table 3.40). Dithioacetals, on the other hand, tend to be more resistant to hydrolysis, but cleavage can be achieved by treatment with mercury(II) salts or by oxidation with either [bis(trifluoroacetoxy)iodo]benzene [723] or periodic acid [724]. Use of the latter reagent can, however, also lead to the conversion of methyl ketones into iodo-methyl ketones [721],... 

Ketone hydrazones can be converted into aliphatic diazo compounds which are, in contrast to nonfluorinated analogs, quite stable at room temperature. 2-Diazo-l,l,1-trifluoropropane is obtained as a solution in diethyl ether or pentane by the oxidation of l,l,l-trifluoropropan-2-one hydrazone using silver oxide.243 Analogously, phenyl trifluoromethyl ketone hydrazone is oxidized to the diazo compound 6 by mercury(II) oxide in alkaline media.362 Bis(per-fluoromethyl)- 7 and bis(perfluoroethyl)diazomethane are prepared by lead(IV) acetate oxidation of the corresponding hydrazones in benzonitrile solution at 0-25 c.244,245... 

The first examples of ortho cycloaddition can be found in a U.S. patent of Ayer and Buchi [1], Benzonitrile and 2-methylbut-2-ene are reported to yield 7,8,8-trimethylbicyclo[4.2.0]octa-2,4-diene-l-carbonitrile upon irradiation under nitrogen with a mercury resonance arc. Similar reactions, all leading to derivatives of bicyclo[4.2.0]octa-2,4-diene-l-carbonitrile occurred when benzonitrile was irradiated in the presence of 2,4,4-trimethylpent-l-ene, ethyl vinyl ether, vinyl acetate, methyl vinyl ketone, and methyl acrylate. The addend pairs para-tolunitrile/oct-l-ene, ort/m-dicyanobenzene/2-methylbut-2-ene, para-dicyanobenzene/but-l-ene, 2,3-dimethylbenzonitrile/propene, and 3,4,5-trimethylbenzonitrile/ethene likewise produced ortho photocycloadducts. 

Cyclization of enone (9) in hexane with boron trifluorideetherate in presence of 1,2-ethanedithiol, followed by hydrolysis with mercury (II) chloride in acetonitrile, yielded the cis-isomer (10) (16%) and transisomer (11) (28%). Reduction of (10) with lithium aluminium hydride in tetrahydrofuran followed by acetylation with acetic anhydride and pyridine gave two epimeric acetates (12) (32%) and (13) (52%) whose configuration was determined by NMR spectroscopy. Oxidation of (12) with Jones reagent afforded ketone (14) which was converted to the a, 3-unsaturated ketone (15) by bromination with pyridinium tribromide in dichloromethane followed by dehydrobromination with lithium carbonate and lithium bromide in dimethylformamide. Ketone (15), on catalytic hydrogenation with Pd-C in the presence of perchloric acid, produced compound (16) (72%) and (14) (17%). The compound (16) was converted to alcohol (17) by reduction with lithium aluminium hydride. 

The anthracyciinone class of anticancer compounds (which includes daunomycin and adriamycin) can be made using a mercury (I I )-promoted alkyne hydration. You saw the synthesis of alkynes in this class on Chapter 9 where we discussed additions of metallated alkynes to ketones. Here is the final step in a synthesis of the anticancer compound deoxydaunomycinone the alkyne is hydrated using Hg2+ in dilute sulfuric acid the sulfuric acid also catalyses the hydrolysis of the phenolic acetate to give the final product. 

Other transition metal salts mediate in similar oxidations. For example, mercury(II) acetate, a milder reagent than LTA, effects a-acetoxylation through a comparable mechanism. However the corresponding yields for these processes are poor. 3,3-Dimethylcyclohexanone, for example, is oxidized to the a-acetoxy derivative in only 14% yield.The, 7-unsaturated ketone, isopugelone, exhibits no oxidation at the a- or a -positions, but affords a product derived from isomerization of the alkene and allylic oxidation. Not surprisingly therefore the reagent has found little synthetic application for this transformation. 

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