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The first catalytic oxygenative allylic transposition of unactivated alkenes into enones has been developed using an oxoammonium salt as a catalyst. This reaction converts various tri- and trans-disubstituted alkenes into their corresponding enones with transposition of their double bonds at ambient temperature in good yields. The use of a less-hindered azaadamantane-type oxoammonium salt as the catalyst and a combination of two distinct stoichiometric oxidants, namely, iodobenzene diacetate and magnesium monoperoxyphthalate hexahydrate (MMPP·6H2O) are essential to facilitate the enone formation efficiently.

A highly enantioselective one-pot synthesis of important building blocks, α-chiral γ-keto esters, has been developed by combining a quinine-catalyzed Michael addition of malononitrile to trans-enones followed by magnesium monoperoxyphthalate (MMPP) oxidation. These synthons proved to be useful reagents for a simple access to challenging cis-α,γ-disubstituted γ-butyrolactones in good diastereoselectivity and high enantiocontrol.

The aza-vinylogous Povarov reaction between α-ketoimines and α,β-unsaturated dimethylhydrazones in the presence of indium trichloride affords 2-acyl-4-alkyl-4-dimethylhydrazonomethyl-1,2,3,4-tetrahydroquinolines with good cis/trans diastereoselectivities. These compounds were readily transformed into highly substituted 2-acylquinolines using a two-reaction sequence involving the oxidative generation of a C-4 nitrile group, followed by its elimination under thermal conditions. Alternatively, a one-pot protocol based on the reaction of hydrazones with magnesium monoperoxyphthalate hexahydrate in refluxing methanol afforded the target 2-acylquinolines in good to excellent yields. This methodology was also extended to the preparation of 2-arylquinolines.

The kinetics of oxidation of aromatic anils to benzaldehyde and azobenzene by magnesium monoperoxyphthalate (MMPP) has been studied in aqueous acetic acid medium. The low dielectric constant of the medium facilitates the reactivity. It has been found that ionic strength of the reaction has no significant effect on rate. The added acrylonitrile has no effect on the reaction rate indicating the absence of free radical mechanism. The added Mn(II) decreases the rate of the reaction, which indicates the involvement of two-electron transfer. Highly negative ΔS# values indicate a structured transition state. The deviation of Hammett plot is noted and a non-linear concave downward curve is obtained for the anils with substituents in the aniline moiety. The observed break in the log kobs versus σ is attributed to the transition state whereas the non-linear concave upward curve is observed for the substituents in the benzaldehyde moiety and a non-linear concacve upward curve is observed for the substituents in the combination of aniline and benzaldehyde moiety and a suitable mechanism is proposed

The catalytic properties of the first generation catalyst meso-tetraphenylporphyriniron(III) chloride and magnesium monoperoxyphthalate (MMPP) as oxidant have been studied in the oxidation of aniline and its substituents in acetic acid medium. The thermodynamic parameters for the oxidation have been determined and discussed. It confirms the Exner relationship (only at the low range of temperatures) and also some of the activation parameters to the isokinetic relationships. The magnesium monoperoxyphthalate oxidation with 18 ortho- meta- and para-substituted anilines fulfills with isokinetic relationship but not to any of the linear free energy relationships. The reaction mechanism and the rate law were proposed.

Oxidative ring cleavage reactions of furans constitute a group of important transformations that have found wide utility in synthetic organic chemistry. These processes have been used to prepare a variety of 1,4-dicarbonyl compounds including 1,4-dioxoalkenes, 4-oxoalkenals, 4-oxoalkenoic acids, and their derivatives such as 4-hydroxybutenolides and 2,5-dialkoxydihydrofurans. Oxidations of furfuryl alcohols (Achmatowicz reaction) and furfuryl amines (aza-Achmatowicz reaction) provide access to highly functionalized heterocyclic structures that have been employed as intermediates in synthetic routes for the preparation of complex molecules including carbohydrates and alkaloids. Complete oxidative degradation of the furan ring affords carboxylic acids; thus the oxygen heterocycle has served as a masked carboxyl group in many synthetic studies. These transformations and their applications in total syntheses are covered in this chapter. Keywords: Furan; Oxidation; 1,4-Dicarbonyl Compounds; 4-Oxoalkenals; 4-Oxoalkenoic Acids; Carboxylic Acids; Ozone; Singlet Oxygen; Ruthenium Tetroxide; Singlet oxygen; 4-Hydroxybutenolides; Achmatowicz Reaction; Hydrogen Peroxide; N-Bromosuccinimide; tert-Butylhydroperoxide; meta-Chloroperbenzoic Acid; Magnesium Monoperoxyphthalate

A novel and efficient method for the preparation of 1,2-diketones is reported. A series of α-diketones were readily prepared by the nitroxyl-radical-catalyzed oxidation of silyl enol ethers using magnesium monoperoxyphthalate hexahydrate (MMPP⋅6H2O) as the co-oxidant.

I3−-selective electrodes with a PVC membrane containing ionic associates of crystal violet (CV) triiodide as electrode-active substance were developed. The pH working range is 2–12, the linearity range of the electrode function is 9×10−6–1×10−1 mol/L, and the electrode function slopes are varying from 44.0 to 62.0 mV/decade, depending on the plasticizers in the membranes. The efficiency of the use of these electrodes for dibenzoyl peroxide and magnesium monoperoxyphthalate determination in pharmaceutical preparations was shown by potentiometric titration methods.

Synthesis of (+)-altholactone has been achieved starting from L-tartaric acid using (2S, 3R,4R,5R)-2-hydroxymethyl-3,4-bis(memoxymethoxy)-5-phenyltetrahydrofuran as key intermediate. The key epoxy ring was introduced by monoperoxyphthalate (MMPP) in high stereoselectivity (8.4:1).

Stress stability testing and forced degradation were used to determine the stability of enalapril maleate (EM) and to find a degradation pathway for the drug. The degradation impurities, formed under different stressed conditions, were investigated by HPLC and UPLC-MS methods. HPLC analysis showed several degradation impurities of which several were already determined, but on oxidation in the presence of magnesium monoperoxyphthalate (MMPP) several impurities of EM were observed which were not yet characterized. The HPLC methods for determination of EM were validated. The linearity of HPLC method was established in the concentration range between 0.5 and 10 microg/mL with correlation coefficient greater than 0.99. The LOD of EM was 0.2 microg/mL and LOQ was 0.5 microg/mL. The validated HPLC method was used to determine the degradation impurities in samples after stress stability testing and forced degradation of EM. In order to identify new degradation impurities of EM after forced degradation UPLC-MS/MS(n), Orbitrap has been used. It was found that new impurities are oxidation products: (S)-1-((S)-2-((S)-1-ethoxy-4-(o,m,p-hydroxyphenyl)-1-oxobutan-2-ylamino)propanoyl)pyrrolidine-2-carboxylic acid, (2S)-1-((2S)-2-((2S)-1-ethoxy-4-hydroxy-1-oxo-4-phenylbutan-2-ylamino)propanoyl)pyrrolidine-2-carboxylic acid. (S)-2-(3-phenylpropylamino)-1-(pyrrolidin-1-yl)propan-1-one was identified as a new degradation impurity.

DNA damage is an important step in carcinogenesis. The Ames assay is a short-term screening of carcinogens that induce DNA damage. Most carcinogens require enzymatic activation through oxidation by cytochrome P450 (CYP450) in the presence of S9 mix. A combination of iron (Fe)(III) porphyrin and an oxidant is also able to oxidize compounds as an alternative metabolic pathway to CYP450. Previously it was reported that a chemical model containing a water-soluble 5,10,15,20-tetrakis(1-methylpyridinium4-yl)porphyrinatoiron(III) chloride (4-MPy) and tert-butyl hydroperoxide (t-BuOOH) activated aromatic amines and amides. In this study, a chemical model composed of an Fe porphyrin, water-insoluble 5,10,15,20-tetrakis(pentafluorophenyl)porphyrinatoiron(III) chloride (F5P) or water-soluble 4-MPy was optimized with an oxidant – t-BuOOH, magnesium monoperoxyphthalate (MPPT), or iodosylbenzene (PhIO). Subsequently the mutagenicity of benzo[a]pyrene (B[a]P) and chrysene in Salmonella typhimurium TA strains was compare...

Heterocyclic amines (HCAs) are a family of mutagenic and carcinogenic compounds produced during cooking or other burning processes, and exist in the environment. HCAs are metabolically activated by cytochrome P450, conjugated by phase II enzymes, to react with guanine bases. The aim of this study is to establish a chemical model for cytochrome P450 as an alternative to S-9 mix for detecting HCA mutagenicity in Salmonella strain. A chemical model was developed by comparing the mutagenicity of 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) in the presence of an iron porphyrin and an oxidant. The iron porphyrin derivatives, water-soluble 5,10,15,20-tetrakis(1-methylpyridinium-4-yl)porphyrinatoiron (III) chloride (4-MPy) or water-insoluble 5,10,15,20-tetrakis (pentafluorophenyl)porphyrinatoiron (III) chloride (F5P), and the oxidant tert-butyl hydroperoxide (t-BuOOH), magnesium monoperoxyphthalate or iodosylbenzene were used. 4-MPy or F5P with t-BuOOH activated Trp-P-2, and the activity was similar with either porphyrin. Water-soluble model has a better chance to detect unstable compound, since the tester strain was exposed in the whole incubation period in the mutation procedure with 4-MPy. The effectiveness of 4-MPy/t-BuOOH was evaluated with other HCAs; IQ, MeIQ, MeIQx, Glu-P-1, Glu-P-2, PhIP, Trp-P-1, MeAαC and AαC. All HCAs except for MeAαC and AαC were mutagenic in Salmonella typhimurium TA1538. MeAαC and AαC were not mutagenic in TA1538, but they were mutagenic in S. typhimurium TA1538/pYG219, which overexpresses O-acetyltranferase on the TA1538 genetic background. Although the HCAs mutagenicity with the chemical model was weaker than that with S-9 mix, the chemical models activated HCAs without S-9 mix in the Ames assay.

Oxidative ring cleavage reactions of furans constitute a group of important transformations that have found wide utility in synthetic organic chemistry. These processes have been used to prepare a variety of 1,4-dicarbonyl compounds including 1,4-dioxoalkenes, 4-oxoalkenals, 4-oxoalkenoic acids, and their derivatives such as 4-hydroxybutenolides and 2,5-dialkoxydihydrofurans. Oxidations of furfuryl alcohols (Achmatowicz reaction) and furfuryl amines (aza-Achmatowicz reaction) provide access to highly functionalized heterocyclic structures that have been employed as intermediates in synthetic routes for the preparation of complex molecules including carbohydrates and alkaloids. Complete oxidative degradation of the furan ring affords carboxylic acids; thus the oxygen heterocycle has served as a masked carboxyl group in many synthetic studies. These transformations and their applications in total syntheses are covered in this chapter. Keywords: Furan; Oxidation; 1,4-Dicarbonyl Compounds; 4-Oxoalkenals; 4-Oxoalkenoic Acids; Carboxylic Acids; Ozone; Singlet Oxygen; Ruthenium Tetroxide; Singlet oxygen; 4-Hydroxybutenolides; Achmatowicz Reaction; Hydrogen Peroxide; N-Bromosuccinimide; tert-Butylhydroperoxide; meta-Chloroperbenzoic Acid; Magnesium Monoperoxyphthalate

The catalytic properties of manganese porphyrins of the second and third generation and magnesium monoperoxyphthalate (MMPP) as oxidant have been studied in oxidation of cyclohexane or cyclooctane under mild conditions. We have found that the structure of manganese porphyrin has an influence on selectivity of the investigated reaction. Apart from main cycloalkanes oxidation products (alcohol and ketone), olefins and epoxides resulting from oxidative dehydrogenation of substrates in the course of reaction, were surprisingly found. This represents the first example of the oxidative dehydrogenation of cycloalkanes with MMPP as oxygen donor. The reaction mechanism is discussed and proposed.

The synthesis of novel monocyclic di- and triphenyl-substituted hydroperoxysultims rac-cis 7 and 8 and sultams 11 and 12, as well as the 3-oxosultams 15 and 16, by oxidation of corresponding salts 1 and 2 with H2O2 in acetic acid is described. For the first time, it was possible to isolate a 3-hydroperoxide (3a) and also to determine the position of the primary oxidizing attack on the C-3 atom of isothiazolium salts 1, which have generally a much lower oxidation reactivity. Novel 3-hydroxysultams 13 and 14 were obtained by oxidation reaction of salts 1 and 2 with magnesium monoperoxyphthalate (MMPP) in acetonitrile in the ultrasound bath. Dedicated to Professor Dr. Jurgen Liebscher on the occasion of his 60th birthday.

An efficient asymmetric synthesis of highly enantioenriched 3-hetero-substituted 2,3-dihydro-1H-isoindolinones is reported. The key step is a diastereoselective nucleophilic addition on N-acylhydrazonium intermediates generated by acidic treatment of hemiaminal precursors bearing an (S)-2-alkoxymethyl-pyrrolidin-1-yl type auxiliary. The auxiliary is removed by an oxidative N,N-bond cleavage with magnesium monoperoxyphthalate.

3-Hydroxy- (17a - j) and 3-alkoxy-4,5,6,7-tetrahydro-benzosultams 18a-m were prepared in good yields by oxidation of the bicyclic isothiazolium salts 10 with magnesium monoperoxyphthalate (MMPP·6H2O) in acetonitrile or corresponding alcohol. A HPLC-API-MS(MS) method was used to monitor the oxidation process of 10 with MMPP. 3-Oxo-4,5,6,7-tetrahydro-benzosultams 19a - c, h, j were also obtained.

The epoxidation, the addition of hypobromous acid, and the hydroboration of 3-methoxy-13α-estra-1,3,5(10),16-tetraene 1 with diborane, catecholborane, and 9-BBN were investigated in order to determine the stereochemical outcome and to synthesize new 13α-estra-1,3,5(10)-trienes for biological and conformational investigations. It was shown that the sterically demanding reagent 9-BBN participated in a preferred β attack (53% 16βOH 10, 34% 17βOH 8, 13% 16αOH 11). This stereochemical result is in agreement with that from another cis addition reaction, the recently described OsO4 dihydroxylation of 1 [Steroids 68 (2003) 113]. With smaller reagents such as B2H6, catecholborane, or magnesium monoperoxyphthalate, a diminished stereoselectivity was observed with only a slight excess of β attack. The ionic trans addition of hypobromous acid gave two 17-bromo-16-alcohols with 16β,17α (4, 76%) and 16α,17β configuration (5, 24%) formed by trans cleavage of the 16,17α- and β-bromonium ion at position 16. The same regioselective and stereoselective course was found for the cleavage of the 16α,17α- and 16β,17β-epoxides (3 and 2) with hydrazoic acid ( 3 →16 βN3,17αOH 7, 2 →16 αN3,17βOH 6). The stereochemistry of the addition reactions to 1 can be explained in terms of a twist-boat conformation involving the C ring of compound 1. From a synthetic viewpoint the synthesis of the β-epoxide 2 from the bromohydrin 4, the cleavage of this epoxide to 16α-substituted-17β-hydroxy compounds, such as 6, and hydroboration/oxidation with 9-BBN to the hitherto unknown 16β-hydroxy compound 10 are useful procedures. The bromohydrin 5 is the first 13α-steroid with a 17β-bromo substituent. X-ray analysis revealed twist-boat and 16β-envelope conformations for rings C and D, respectively.

The oxidation reaction of isothiazolium salts 6 with magnesium monoperoxyphthalate (MMPP) in ethanol or water in the ultrasound bath affords new 3-hydroxysultams 10 and 3-alkoxysultams 15 in very high yields. A HPLC-API-MS(MS) method was used for monitoring of the oxidation of salts 6 with MMPP.

DNA damage is a critical factor in carcinogenesis. The Ames assay is a short-term test that screens for DNA-damaging agents. To be detected in the assay, most carcinogens require oxidation by cytochrome P450, a component of the liver homogenate preparation (S9 mix) that is traditionally used to metabolize promutagens to an active form in vitro. A combination of iron(III) porphyrin plus an oxidant activates many promutagens by mimicking cytochrome P450 metabolism. We previously reported that the mutagenicity of the N -nitrosodialkylamines was detected following reaction with tetrakis(pentafluorophenyl)porphyrinatoiron(III) chloride (Fe(F 5 P)Cl) plus tert -butyl hydroperoxide ( t -BuOOH), which yielded the same alcohols and aldehydes as the enzymatic reaction. In the present study, to extend the scope of biomimetic models, we tested the mutagenicity of other carcinogens exposed to chemical oxidation systems. We investigated the optimal assay conditions for the models in Salmonella typhimurium TA1538, a strain sensitive to frame-shift mutagens. We activated 2-aminofluorene (AF), benzo[ a ]pyrene (B[ a ]P), a tryptophane pyrolysate 3-amino-1-methyl- 5H -pyrido[4,3- b ]indole (Trp-P-2), and 2-acetylaminofluorene (AAF) with Fe(F 5 P)Cl plus an oxidant— t -BuOOH, m -chloroperoxybenzoic acid ( m CPBA), or magnesium monoperoxyphthalate (MPPT)—and we noted the effect of three solvents—acetonitrile (CH 3 CN),1,4-dioxane, and N , N -dimethylformamide (DMF)—on AF activation. All the promutagens became mutagenic in the presence of Fe(F 5 P)Cl plus an oxidant, with the effectiveness of the oxidant varying with the chemical. Aromatic amines, for example, showed the strongest mutagenicity with t -BuOOH whereas polycyclic hydrocarbons showed the strongest mutagenicity with m CPBA. All the promutagens were mutagenic in the presence of Fe(F 5 P)Cl plus MPPT. For AF activation, the order of effectiveness of the solvents was CH 3 CN>1,4-dioxane>DMF. The results suggested that these systems would serve as useful models for microsomal activating systems.

Oxidation of 4-cyanophenyl 2,5-anhydro-1,6-dithio-α- d -glucoseptanoside with magnesium monoperoxyphthalate (MMPP) resulted in a mixture containing two endo - and two exo -monosulfoxides as well as two endo - exo bis-sulfoxides differing in the chirality of the sulfoxide groups. Besides the aforementioned six products a further endo – exo bis-sulfoxide isomer as well as an exo -sulfone was obtained via oxidation with NaIO 4 . Oxidation of 4-nitrophenyl 1,5-dithio-β- d -arabinopyranoside with MMPP yielded only two endo -sulfoxides, while oxidation with NaIO 4 in turn led to cleavage of the carbohydrate ring. The formed dialdehyde was stabilized by cyclisation to a hemiacetal, which on further treatment with MMPP afforded an exo -monosulfoxide. The position of oxidation as well as the chirality of the respective sulfoxide groups was established by NMR spectroscopy and X-ray crystallography.

Unsupported, moist magnesium monoperoxyphthalate (MMPP) was found to oxidize various phosphorus keto ylides to the corresponding vicinal tricarbonyls selectively in dichloromethane at ambient temperature in good to excellent yields.

Reactions of O-ethyl S-(2-diisopropyl-amino)ethyl methylphosphonothiolate, VX 1, were investigated with five oxidizing agents. In all the cases, the formation of the VX N-oxide 7 was observed prior to the subsequent oxidation and hydrolysis into the nontoxic O-ethyl methylphosphonate 2. Magnesium monoperoxyphthalate (MMPP) is probably one of the most active reagents to achieve the complete detoxification of VX 1. The decontamination using MMPP was also extended with success to soman 13, a G-type agent. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:485–490, 2001

A series of halfsandwich ruthenium sulfinato complexes [CpRu(PR'3)2(SO2R)] (R = Me, CH2Ph, C2H4Ph, Ph, 4-C6H4Me; PR'3 = PMe3, 1/2 dppm) with various electronic and steric environments around the ruthenium centre, have been prepared by insertion of SO2 into a ruthenium carbon bond, by a direct ligand exchange reaction, or by oxidation of thiolato complexes with 3-chloroperoxybenzoic acid. The chiral complexes [CpRu(CO )(PPh3)(SO2R)] (R = Me, CH2Ph, Ph) were obtained similarly by oxidation of the corresponding thiolates with magnesium monoperoxyphthalate. Alkylation of the sulfinato complexes with oxonium salts [R"3O]X (R" = Me, Et; X = BF4 , PF6) gave ruthenium complexes of sulfinic acid esters, [CpRu(L)(L′)(S(O)(OR″)R)]X in high yields and, for the chiral complexes, up to 82% de. The esters may be detached from the metal by ligand exchange with acetonitrile. Stronger nucleophiles such as I- or SMe- dealkylate the coordinated sulfinic acid esters.

The selective oxidative cleavage of the SAMP-hydrazone moiety of 4-silyloxy-3-enal hydrazones 6 , leading to the corresponding 4-silyloxy-3-alkenenitriles 7 , is reported. A clean, good yielding transformation was observed when m -CPBA in CH 2 Cl 2 was used as the oxidant, the presence of suspended solid NaHCO 3 being essential in preventing hydrolysis of the silyl enol ether moiety. Use of magnesium monoperoxyphthalate (MMPP) led to over-oxidated products, while hydrogen peroxide, in the presence of catalytic methyltrioxorhenium (MTO), was ineffective. Independent measurements of the enantiomeric excesses for compounds 7 demonstrated the absence of racemization during the process.

A simple, efficient and chemoselective, non-aqueous procedure for oxidation of sulfides to the corresponding sulfones with magnesium monoperoxyphthalate on hydrated silica gel has been developed.

Ni(II) chelated peptides of the form NH2-Xaa-Xaa-His-CONH2 (Ni(II)·Xaa-Xaa-His) mediate deoxyribose damage through C4‘−H abstraction of a targeted nucleotide when activated with KHSO5 (oxone), MMPP (magnesium monoperoxyphthalate), or H2O2. The products released and identified in comparison to the authentic C4‘−H oxidant Fe(II)·bleomycin included fragmented DNA terminating in 5‘-phosphates, 3‘-phosphates, and 3‘-phosphoglycolates; upon treatment of Ni(II)·Xaa-Xaa-His cleavage reactions with NaOH or NH2NH2, fragmented DNA 3‘-termini were released consistent with the intermediate formation of keto-aldehyde abasic (alkaline-labile) sites. In addition, nucleobases and nucleobase propenals were detected in proportions consistent with abasic site and 3‘-phosphoglycolate termini formation, respectively. These results indicate that Ni(II)·Xaa-Xaa-His metallopeptides, like Fe(II)·bleomycin, degrade DNA through two pathways resulting from an initial C4‘−H modification. Importantly, the partitioning between these two...

Reaction of tricyclic azetidinones 1–5 (azetobenzoxazine, -thiazine, -thiazepine and -azepine derivatives) with trifluoroacetic acid led to bicyclic thioesters 6–13 . There is evidence for an intermolecular reaction, a possible mechanism is discussed. The structure of two representative thioesters ( 8 and 9 ) was elucidated by different NMR experiments, complete assignments of 1 H- and 13 C-chemical shifts are given. Reaction of the azetobenzoxazine 2 with sodium periodate and magnesium monoperoxyphthalate led to the sulfoxide 18 and the sulfone 19 , respectively.

Oxidative ring opening reaction of methyl 9,12-epoxy-9,11-octadecadienoate (1) with excess magnesium monoperoxyphthalate (MMPP) under ultrasonic irradiation in water furnished methyl 9,12-dioxo-cis-10-octadecenoate (2, 93%). Reaction of compound 1 with 10 molar equivalents of m-chloroperoxybenzoic acid (m-CPBA) in dichloromethane gave methyl cis-10,11-epoxy-9,12-dioxooctadecanoate (3, 91.5%) exclusively. Under ultrasonic irradiation, compound 1 reacted with m-CPBA to give a mixture of compounds 2 (60%) and 3 (40%). Isomerization of methyl 9,12-dioxo-cis-10-octadecenoate (2) to the corresponding trans-isomer (methyl 9,12-dioxo-trans-10-octadecenoate, 4, 95%) was achieved in the presence of pyridine in water under ultrasonic irradiation. Compound 4, alternatively prepared in 95% yield from compound 1 by reaction with pyridinium chlorochromate, was readily epoxidized with hydrogen peroxide to methyl trans-10,11-epoxy-9,12-dioxooctadecanoate (5, 95%). The corresponding cis-isomer (methyl 9,12-dioxo-cis-10-octadecenoate, 2) resisted all attempts by MMPP and hydrogen peroxide to be epoxidized. The structures of the various derivatives (2–5) of compound 1 were identified by a combination of spectroscopic techniques including IR, 1H- and 13C-NMR spectroscopy.

A variety of unsubstituted and mono- or di-substituted cycloalkanones can be oxidised with modest excess of magnesium monoperoxyphthalate hexahydrate in acetonitrile to produce the corresponding lactones in a facile, selective, and high yielding manner.

Magnesium monoperoxyphthalate oxidation of unsubstituted and substituted cyclohexanones has been carried out in acetonitrile in the presence of bentonite clay, affording the corresponding e-caprolactones in fairly good yields.

The title oxidation has been investigated in acetonitrile. The substrates examined include alkyl aryl, diaryl, dialkyl, and cyclic sulphides, which afforded the corresponding sulphoxides in good to excellent yields under neutral and mild conditions.

Optically active α- and α,β-substituted aldehyde hydrazones 2, 4, and 7, which are readily available by asymmetric alkylation. Michael addition or [2,3]-Wittig rearrangement of chiral hydrazones can be transformed into nitriles 3 and 5 or cyanohydrins 8 by MMPP mediated oxidation, respectively. This synthetic sequence offers a C-C connective entry into optically active functionalised nitriles with good overall yields (30—75 %) together with high diastereo- and enantioselectivities (de = 76-≥ 96%. ee72- ≥97%).

Magnesium monoperoxyphthalate (MMPP) oxidizes a variety of organic molecules in neutral homogeneous aqueous solutions at room temperature. A water-soluble porphyrin complex, meso -tetrakis(4-N-methylpyridyl)porphyrinatomanganese(III) chloride, Mn(III)TMPyP(4) Cl, acts as an efficient catalyst for the epoxidation and hydroxylation of water-soluble hydrocarbons.

Ultrasound (20 kHz)-assisted epoxidation of unsaturated fatty esters with m-chloroperoxybenzoic acid (MCPBA) in water was successfully carried out in less than 30 min. Epoxidation of unsaturated fatty esters containing an internal ethylenic system was more readily accomplished than with substrates containing a terminal ethylenic bond. The rate of epoxidation of the same unsaturated fatty esters using magnesium monoperoxyphthalate in aqueous ethanol was much slower than reactions with MCPBA.

A novel method allows the synthesis of 1,2-diketones under mild conditions through nitroxyl-radical catalyzed oxidation of silyl enol ethers with magnesium monoperoxyphthalate as the oxidant.

Synthesis of 20-Carbaldehydes and 20-Carbonitriles of the Pregnane Series Starting with (20S)-20-Hydroxymethylpregna-1,4-dien-3-one An efficient six-step approach to 3-protected (20S)-3β-hydroxypregna-1,5-diene-20-carbaldehydes 8 with potential importance in the synthesis of vitamin D analogues was developed starting with (20S)-20-hydroxymethylpregna-1,4-dien-3-one (1). Oxidation of the 22-hydroxy group of 1 by means of periodinane 2 (Dess-Martin reagent) furnished the aldehyde 3 without epimerization. 3 was protected selectively at C-22 as dimethyl acetal 5. Isomerization to 6 and subsequent reduction of the 3-carbonyl group with calcium borohydride furnished the 3β-alcohol 7a with high stereoselectivity. Cleavage of the acetal to 8a occurred in a homogeneous solution of acetic acid in the presence of small amounts of water and trifluoroacetic acid. After protection of the 3-OH group 8b–d were obtained in 54% overall yield. The in situ generated aldehyde N,N-dimethylhydrazones of 3, 8a, and 8b were converted in high yields with excellent chemoselectivity into the nitriles 12, 15a, and 15b with magnesium monoperoxyphthalate hexahydrate. The uniform (20S) stereochemistry of 3 and 8a–d was elucidated by 1H-NMR investigations.

Oxidation of metam [CH 3 NHC(S)SNa] with H 2 O 2 produces the sulfenate [CH 3 NHC(S)SONa] and sulfinate [CH 3 NHC(S)SO 2 Na], depending on the amount of oxidant, but the sulfonate [CH 3 NHC(S)SO 3 Na] and corresponding thiocarbamates [CH 3 NHC(O)SO n Na, n=0, 1, 2, or 3] are not observed on the basis of comparisons with standards. Metam in aqueous solution is converted by mouse microsomes with NADPH to the sulfenate and methyl isothiocyanate (MITC), by the arachidonate/lipoxygenase and glucose oxidase systems to the sulfenate, by magnesium monoperoxyphthalate to MITC, methyl isocyanate (MIC), and methylamine, and by sunlight to MITC

This paper describes the oxidation of an α,β-diarylpropane lignin dimer model and other dimethoxyarenes by several iron porphyrin-based biomimetic systems. From 1-(3,4-dimethoxyphenyl)-2-phenylpropanol (1), three types of products are identified: the 3,4-dimethoxybenzaldehyde derived from the C α -C β cleavage of the propyl side chain and either quinones or muconic dimethyl esters resulting from oxidations at the level of the dimethoxyaryl group. The selectivity of the reaction is discussed with respect to the nature and reactivity of the high-valent iron-oxo species formed upon reaction of the oxidants, H 2 O 2 or magnesium monoperoxyphthalate (MMP), with the iron porphyrins

Magnesium monoperoxyphthalate and urea–hydrogen peroxide–acetic anhydride are effective reagents in the oxidation of benzaldehyde to benzoic acid and o- and p-methoxybenzaldehyde to the corresponding phenols. On the other hand, aromatic aldehydes, including the isomeric methoxybenzaldehydes, are oxidised to the corresponding benzoic acid derivatives in good to excellent yields by the hydroperoxide anion generated from urea–hydrogen peroxide.

Whereas the oxidative cleavage of bicyclic isoxazolidines 5 (2-phenylperhydroisoxazolo[2,3-a]pyridine) and 9 (6-(2-benzyloxyethyl)- 8 -(3-phenylsulfonylpropyl)-7 -oxa-1-azabicyclo-[3.2.1]octane) with magnesium monoperoxyphthalate (MMPP) significantly favours the formation of the more substituted tetrahydropyridine N-oxides, 3-chloroperoxybenzoic acid (mCPBA) is shown to favour the less substituted nitrone 10 in reaction with the more substituted isoxazolidine 9.

Treatment of N-alkyl-N-allenylmethylanilines with magnesium monoperoxyphthalate in methanol–water underwent tandem transformations to furnish N-alkyl-2-ethenylindoles in good yield.

Dialkylfurans were reacted with magnesium monoperoxyphtalate (MMPP) in methanol to give 2,5-dimethoxy-2,5-dihydrofurans in high yields under mild reaction conditions.

Biomimetic oxidation of unactivated arenes with magnesium monoperoxyphthalate and a fluorinated iron porphyrin as catalyst lead mainly to p-quinones without involving phenols as reaction intermediates.