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Die Olefine (I) reagieren mit Malonsaure/Mn(III)-acetat unter Bildung der isomeren Dioxaspirononadione (II)-(IV).

Z-Methyl-pyiidin (I) reagiert mit Aceton (II) und 1-Hexen (III) in Gegenwart von Mangan(III)-acetat zu den beiden Pyridyl-nonanonen (IV) und (V).

Die Titelreaktion liefert in Acetanhydrid als Hauptprodukt Succinanhydrid neben Acetoxyessigsaure als Hauptanteil der Nebenprodukte.

Manganese(III)-promoted addition of various 1,3-dicarbonyl compounds to enol ethers or terminal enol esters, followed by hydrolysis of the resulting adducts and base catalyzed aldol cyclization provides an effective process for the synthesis of a wide range of fused and spiro 2-cyclopentenones.

The reaction of 2-(4-methoxyphenyl)-4-chromanone with Mn(OAc)3 in the presence of LiCl gave 3,3-dichloro-2-(4-methoxyphenyl)-4-chromanone. The reactions of 2-phenyl-4-chromanone, 1-phenyl-1-propanone, 1,2-diphenylethanone, and 1-tetralone similarly yielded α,α-dichloro derivatives in good yields. 2,2,2-Trichloroacetophenones were obtained from 2,2-dichloroacetophenones, but in the absence of LiCl, 2,2-dichloroacetophenones gave 2,2,3,3-tetrachloro-1,4-butanediones. KCl, NaCl, NH4Cl, AlCl3, and CaCl2 were also employed as the Cl− ion source. Synthetic applicability and the reaction mechanisms are discussed briefly.

The reactions of 4-methoxy-, 7-methoxy-, 6,7-dimethoxy-, and 7,8-dimethoxycoumarins with manganese(III) acetate in boiling acetic acid containing acetic anhydride gave 3-(acetoxymethyl) coumarins as the major product. The reactions of coumarin, and 6-methoxy- and 8-methoxycoumarins with manganese(III) acetate yielded a mixture of 3-(diacetoxymethyl)- and nuclear acetoxymethylated coumarins. The reaction of 7-methoxycoumarin with lead(IV) acetate gave 7-methoxy-3-methylcoumarin.

Bei der Oxidation von Aceton (I) mit Mn(III)-acetat-dihydrat in Eisessig/Acetanhydrid werden Acetonylacetat (II) und das Diketon (III) erhalten.

The oxidation of 3,3-diphenyl-2-propenoic acid with manganese(III) acetate in boiling acetic acid gave 3,3-diphenyl-2-propenyl acetate, 4-acetoxymethyl-5,5-diphenyltetrahydro-2-furanone, 3,3-diphenyl-2-propenal, 5,5-diphenyl-2,5-dihydro-2-furanone, 4-acetoxy-5,5-diphenyltetrahydro-2-furanone, benzophenone, and 2-oxo-5,5-diphenyltetrahydro-4-furancarboxylic acid. The reaction pathways are discussed.

The reaction of 4′-methoxyacetophenone with manganese(III) acetate in the presence of ammonium chloride yielded 2-chloro-4′-methoxyacetophenone (2a) and 2,2-dichloro-4′-methoxyacetophenone (3a). The reaction of 2a with these reagents gave 3a, 4′-methoxy-2,2,2-trichloroacetophenone, and 1,4-bis(4-methoxyphenyl)-2,2,3,3-tetrachloro-1,4-butanedione (8a). The reactions of 2a and 2-bromoacetophenone with manganese (III) acetate yielded the corresponding 2,3-dihalo-1,4-diphenyl-1,4-butanediones, 1,4-diphenyl-2-halo-2-butene-1,4-diones, 2,3-dihalo-2-butene-1,4-diones, 2,2-dibromoacetophenone, and 8a. The reaction pathways are discussed.

Radical oxidation and addition reactions of anthracene (1), 9-methylanthracene (2) and 9-phenylanthracene (3) were investigated with dimethyl malonate (4) in the presence of ceric ammonium nitrate (CAN) and manganese(III) acetate (Mn(OAc)3). Although mostly anthraquinone derivatives and bianthrone were obtained with CAN, substituted 9,10-dihydroanthracene and 9,10-substituted anthracene derivatives were obtained with Mn(OAc)3. Dimethylmalonyl addition products (5a, 33 % and 5b, 42 %) were obtained in higher yield than quinones (5d, 8 % and 5e, 3 %) using Mn(OAc)3 as oxidant. 9a (96 %) and 9b (84 %) were synthesized in high yield and substitution products (7a, 44 % and 8b, 56 %) were obtained in higher yields than quinones (5d and 5e) using CAN as oxidant. The reactions were carried out in non-acidic medium (dichloromethane and methanol). Based on the structures of the isolated products a mechanism for these transformations was proposed.

A three step synthesis of various thiobarbiturate derivatives 17-24 was established. The first step is mediated by Mn(OAc)₃, in order to generate a carbon-carbon bond between a terminal alkene and malonate. Derivatives 1-8 were obtained in moderate to good yields under mild conditions. This key step allows synthesis of a wide variety of lipophilic thiobarbiturates, which could be tested for their anticonvulsive or anesthesic potential.

cDe part ment of Chem is try, Fac ulty of Sci ence, Razi Uni ver sity, Kermanshah, Iran d De part ment of Chem is try, Fac ulty of Sci ence, Shi raz Uni ver sity, Shi raz, Iran A novel triiodide sen sor based on (tetrachlorophenylporphyrinato) man ga nese(III) ac e tate is de scribed. The elec trode is pre pared by in cor po rat ing the ionophores into plasticized PVC mem brane, which is di rectly coated on the sur face of a graph ite elec trode. The re sult ing elec trode has a lin ear dy namic range be tween 1.0 10 -1 and 7.9 10 -6 M with a near-Nernstian slope of -66.5 1.0 mV per de cade and a de tec tion limit of 6.0 10 -6 M. The in flu ences of lipophilic ad di tives on the re sponse prop er ties of the elec trode were in ves ti gated. The pro posed sen sor re vealed high se lec tiv ity for triiodide over a wide va ri ety of other an ions and could be used in a pH range 2-9. The elec trode can be used for at least 3 months with out any con sid er able di ver gence in po ten tial. It was ap plied as in di ca tor elec trode in potentiometric ti tra tion of ascor bic acid and triiodide ions.

Efficient syntheses of new 4- hydroxymethyl -5,5-dimethyl-2- thiophen2-yl -4,5-dihydrofuran-3-carbonitrile 3a and 4- hydroxymethyl -5,5-dimethyl-2- phenyl-4,5-dihydrofuran-3-carbonitrile 3b were achieved via oxidative addition and cyclization reaction of 3-oxo-3- thiophen-2-yl propanenitrile 1a and 3-oxo-3- phenylpropanenitrile 1b with 3-methylbut-2-en-1-ol 2a in the presence of manganese III acetate. The structures of the compounds 3a and 3b were determined on the basis of spectral data IR, NMR and MS . All spectral data are in good agreement with the proposed structures of compounds.

A convenient microwave irradiation protocol was utilized for the synthesis of b-ketosulfones 1–5 in good yields. These sulfones reacted with alkenes through a radical oxidative cyclization mediated by Mn(OAc)3. Dihydrofurans 6–10 were obtained in moderate to good yields starting from 1,1-disubstituted alkenes. Dihydrofurans 11–15 were synthesized in moderate yields and unexpected cyclopropanes 16–19 were obtained in low yields starting from 1,2-disubstituted alkenes. This protocol offers access to various dihydrofurans which could be tested for their antiparasitic potential.

Anthracene, 9-methylanthracene, 9-phenylanthracene, 9-chloroanthracene, 9-anthracenecarbaldehyde, 9,10-diphenylanthracene, 9,10-dibromoanthracene, 9,10-anthracenedicarbaldehyde, 9,10-ditolylanthracene, 9-cyanoanthracene, 9,10-dicyanoanthracene, 9-cyano-10-methoxyanthracene, 9-chloro-10-cyanoanthracene and dibenz[a,h]anthracene were titrated redoximetrically with manganese(III) acetate in glacial acetic acid. Titrations were carried out at 60 °C, both directly and indirectly. Because the direct titrations are time consuming, the indirect titrations were found to be the more practical. For the indirect titrations a hydroquinone solution was used as a back-titrant. The end-points were determined potentiometrically using a redox platinum and silver-silver chloride electrode assembly. The first nine compounds listed above participated in two-electron redox reactions to produce anthraquinone and its derivatives. The remaining five compounds did not undergo a redox reaction. This is probably due to the very strong electron-withdrawing effect of the cyano group or to the fused benzene rings.

Etude de la cyclisation par l'acetate de manganese III de cetoacides ou d'alcoxycarbonylacides en γ-lactones: par exemple cyclisation de l'acide cyclohexene-2 acetylacetique en perhydro cyclopenta [cd] benzofurannone-2; application au malonate de cyclohexene-2yle a l'acide methyl-7 oxo-3 octene-6oique, a l'acide β-oxo cyclohexene-3 propionique et a l'acide cyclopentene-2 acetylacetique (obtention de perhydro furo [4,3,2-cd] benzofurannedione, d'oxatricyclododecanedione, de perhydro cyclopenta [c] furannedione-1,6, de perhydro indeno [1,6-bc] furannedione-2,3 et de perhydro indeno [2,1-b:6,1-b'-c'] difurannedione

Intramolecular arylation of a cyclic β-diketone using Mn(OAc)3 is applied for construction of the spirocyclic structure in Fredericamycin A.

The reaction of 1,1-diphenylethene with malonic acid in the presence of manganese(III) acetate gave 3,3,8,8-tetraphenyl-2,7-dioxaspiro[4.4]nonane-1,6-dione and 4,4-diphenyl-2-(2,2-diphenylethenyl)-4-butanolide. Similar reactions with 1,1-bis(4-methoxyphenyl)ethene, methylenecyclohexane, 2-phenylpropene, 1-octene, and cyclohexene yielded the corresponding 2,7-dioxaspiro[4.4]nonane-1,6-diones.

The oxidation of methylferrocene with manganese(III) acetate in acetic acid yielded three products which arose from the ferrocenylmethylation of methylferrocene. The reaction of methylferrocene with manganese(III) acetate in presence of styrene was also examined.

The reaction of biphenylene with manganese (III) acetate gave 2-acetoxybiphenylene, 2-formylbiphenylene, 2-(acetoxymethyl)biphenylene, and 7-oxa-10,11-benzotricyclo[4.3.2.0]undeca-2,4,10-trien-8-one. The reaction pathways are discussed.

The formation of hydroxy acetates in the reaction of some alkenes with lead(IV), cobalt(III), and manganese(III) in acetic acid is demonstrated to involve the intermediacy of alkene radical-cations. A study employing a range of aryl-substituted alkenes has shown that there is an inverse relationship between the yield of hydroxy acetate and the ionisation potential of the organic substrate. The electron deficiency in the radica-cations derived from these alkenes appears to be localised on the double bond: no evidence could be obtained for reaction at the aromatic ring. The introduction of a chlorine atom into this ring had the effect of repressing electron-transfer in cobalt(III) and manganese(III) oxidations but not in those involving lead(IV).

The effect of added sodium bromide on the allylic oxidation of olefins by cobalt(III), manganese(III), and cerium(IV) acetates has been studied. Sodium bromide strongly accelerated the oxidation of cyclohexene by these oxidants to give cyclohex-2-enyl acetate in good yield. Only one product was obtained in the oxidation of cycloalkenes, but two allylic acetates were obtained in the oxidations of methyl-substituted cyclohexenes, which have two kinds of allylic hydrogen. A mechanism involving hydrogen abstraction from allylic sites by bromine radicals is suggested.

The selectivity of radical generation in the oxidation of carbonyl compounds by manganese(III) has been studied in two ways. Competitive reaction of acetic and propionic acids under conditions in which the resultant radicals are trapped efficiently by an alkene suggests that propionic acid reacts some 3.8 times more readily than does acetic acid. Oxidation of butanone under similar conditions gives products in the formation of which reaction has occurred 2.9 times more readily at C-3 of butanone than at C-1. However, this ratio reflects a combination of chain propagation and of initiation by manganese(III) oxidation. When propagation is effectively eliminated, the C-1 position is the more reactive. The significance of these observations on the mechanism of oxidation of carbonyl compounds by manganese(III) is discussed. It is suggested that enol radical-cations can be formed in the reaction but that these do not give carbonyl-stabilised radicals by deprotonation.

Reactions of metal acetates with organic disulphides in dichloromethane–trifluoroacetic acid in the presence of unsaturated nitriles give trifluoroacetoxy sulphides, which on hydrolysis readily afford mixtures of the regioisomeric hydroxy sulphides. Optimum yields were obtained with manganese(III)acetate. The mixtures of regioisomeric trifluoroacetoxy sulphides react with acetonitrile under Ritter conditions to give further mixtures of regioisomeric vicinal acetamido sulphides. The regiochemistry of these reactions is discussed. Hydrolysis of the mixtures of trifluoroacetoxy sulphides in aqueous cobalt chloride gives substituted lactones. This high-yield transformation depends upon lactonisation proceeding via an episulphonium ion intermediate; hence conversion of unsaturated nitriles into sulphenyl lactones is characterised by good regiocontrol.

A systematic investigation has been carried out into the effect of different reaction parameters on the oxidation of oct-1-ene by manganese(III) acetate in acetic acid and acetic anhydride. The most important factor in dictating the ratio of products is the composition of the solvent. In the absence of anhydride γ-decanolactone is virtually the sole product. Even small quantitites of anhydride lead to the lactone being replaced by other products derived from cationic intermediates C6H13[graphic omitted]HCH2COX (X = OH or OAc). Further increases in the amount of anhydride encourage the formation of decanoic acid until, in 90% anhydride, this becomes the predominant product. The results cannot be interpreted simply in terms of competition for the alkene by the radicals ·CH2CO2H and ·CH2COOCOCH3. Decanoic acid formation is also favoured by low temperatures, low concentration of oxidants, and by the addition of acetate ions. A comparision is made of the efficiency of addition when the initiating species is manganese(III) or a peroxide.

Olefins are oxidised by manganese(III) acetate in acetic acid at 70° to give allylic acetates in the presence of metal halide catalysts. With potassium bromide as catalyst, cyclohexene gives cyclohex-2-enyl acetate in 75% yield. The mechanism, generality, and synthetic value of the reaction are discussed.

Toluenes give benzyl acetates with manganese(III) acetate by a radical process involving potassium bromide as catalyst, but without catalyst oxidation is by one-electron transfer.