Trifluoroperacetic Acid Research Articles

ChemInform Abstract: PREPARATION OF α‐NITRO OLEFINS FROM α‐HALO KETOXIMES

α-Nitro olefins were synthesized from α-haloketones through oximation and subsequent oxidation with trifluoroperacetic acid.

Synthesis of isomeric 3-nitro-4-phenylfuroxane and 4-nitro-3-phenylfuroxane

1. A study was carried out on the feasibility of synthesizing isomeric 3-nitro-4-phenylfuroxane and 4-nitro-3-phenylfuroxane by means of the trifluoroperacetic acid oxidation of the corresponding isomeric 3-amino-4-phenylfuroxane and 4-amino-3-phenylfuroxane. 2. 3-Nitro-4-phenylfuroxane, which is the first reported 3-nitro derivative of furoxane, was synthesized.

Preparation of α-Nitro Olefins from α-Halo Ketoximes

Abstract α-Nitro olefins were synthesized from α-haloketones through oximation and subsequent oxidation with trifluoroperacetic acid.

Notiz über die Bestimmung der absoluten Konfiguration von (+)‐2‐Hydroxy‐2, 3‐dimethylbuttersäure

Note on the Determination of the Absolute Configuration of (+)‐2‐Hydroxy‐2, 3‐dimethylbutyric AcidChemical correlation of the title compound 1 with (S)‐3‐isopropyl‐3‐methyl‐5‐trimethylsilyl‐4‐penten‐2‐one (2) showed (+)‐1 to have (S)‐configuration. Key step was the Baeyer‐Villiger oxidation of a very hindered, optically active methyl keton to the corresponding acetoxy compound with trifluoroperacetic acid using slightly modified buffer conditions. It is found, that the erythro/threo assignment of an α, α‐disubstituted β‐hydroxyester intermediate can be based on the observation, that the 1H‐NMR. signal of HC(β) of the erythro isomer appears at lower field than that of the threo isomer.

Oxydation d'alcaloïdes indoliques par l'acide trifluoroperacétique

The oxidation of several indolic alcaloids with trifluoroperacetic acid gives a variety of products resulting from attack at the 2 (7) double bond. Tentative mechanisms are proposed. There is no hydroxylation of the aromatic nucleus.

Trifluoroperacetic acid. Oxidation of aromatic rings

Trifluoroperacetic acid. Oxidation of aromatic rings

Non‐enzymatic oxidation and reduction chemical model systems for the study of pesticide transformation

Abstract Many nonenzymatic chemical oxidative and reductive model systems yield the same products as in vivo systems and provide elegant means to demonstrate the degradation fate of pesticides in living target and non‐target systems. Enzymatic metabolic reactions are of four types: oxidation, reduction, hydrolysis, and synthesis. Reactions involving oxygenases (mixed function oxidases) or reductases are most readily modelled in vitro, and several classes of insecticides have been examined using model systems designed to imitate in vivo processes catalyzed by these enzymes. Several oxidative model systems have been described: the Udenfriend ascorbic acid oxidation systems (AAOS), the Fenton and modified Fenton oxidation systems, the titanous chloride system, the peracetic acid system, the peroxytrifluoroacetic acid system, and the m‐chloroperoxybenzoic acid system. A variety of substrate insecticides have been examined using these oxidative systems including organochlorine compounds (aldrin), carbamates (m...

ChemInform Abstract: NITRAMINO ACIDS. SYNTHESIS AND BIOLOGICAL EVALUATION OF 1‐NITROPROLINE, 1‐NITROPIPECOLIC ACID, AND N‐NITROSARCOSINE

AbstractAus den entsprechenden Aminen entstehen die N‐Nitroso‐Verbindungen (b‐Reihe), die mit Trifluorperessigsäure zu den N‐Nitro‐Verbindungen (c‐Reihe) oxidiert werden.

Preparation of cyclo‐Hexasulfur Oxide, S6O

S6O, the smallest known cyclopolysulfur oxide, has been prepared by oxidation of S6 with trifluoroperacetic acid. Depending upon the conditions, either α- or β-S6O is formed; the crystals differ in their physical properties.

An example of the oxidative de-esterification of an isopropyl ester. Its role in the metabolism of the herbicide flampropisopropyl.

1. Two mammalian metabolites of the herbicidal ester, flamprop-isopropyl (BARNON), have been characterized as products of omega-hydroxylation of the isopropoxycarbonyl grouping (-CO2 CHMe 2). 2. Hydroxylation at the methine group of this moiety, to afford an unstable lactol (-CO2C(OH)Me2) and thence the corresponding carboxylic acid also appears to occur. On the basis of experiments with rat liver microsomes, this pathway to the acid may be as important as the esterase-catalysed route. 3. Biomimetic oxidation studies with peroxytrifluoroacetic acid of a simple model of the herbicide (isopropyl acetate) have provided confirmation of the feasibility of the novel biotransformation.

Nitramino acids. Synthesis and biological evaluation of 1-nitroproline, 1-nitropipecolic acid, and N-nitrosarcosine

The N-nitro derivatives of secondary alpha-amino acids, viz., 1-nitroproline (1a) (L and D), 1-nitro-DL-pipecolic acid (2a), and N-nitrosarcosine (3a), were prepared by the oxidation of the corresponding nitrosamino acids with peroxytrifluoroacetic acid. These nitramino acids (1a-3a) were not active against Escherichia coli, Candida albicans, Pseudomonas aeruginosa, or Mycobacterium smegmatis, and 1a and 2a did not show mutagenic activity in a Salmonella typhimurium TA-100 system, with or without added rat liver 9000g supernatant fraction. The marginal mutagenicity of 3a in this system suggests that additional work should be done to assess its carcinogenic-mutagenic potential.

The electronic structure of peracids. Functional models for cytochrome p-450

An extensive set of ground state ab initio and semiempirical molecular orbital calculations has been performed on both peroxytrifluoroacetic and peroxyacetic acids. The equilibrium geometry of peroxyacetic acid was calculated with the STO-3G and MINDO/3 methods, and peroxide rotational barriers for both peracids were obtained with STO-3G and PCILO. Extended basis set calculations with the 6-31G ** basis were performed for both peracids to compare the electronic structures of these two compounds. Electrostatic potential maps in the region of the peroxide bonds of both peracids were also calculated using INDO wavefunetions. These results are discussed with respect to the enhanced reactivity of peroxytrifluoracetic acid relative to peroxyacetic acid and the nature of the oxygen electrophilicity in these compounds and by analogy in cytochrome P-450, for which peroxytrifluoroacetic acid is considered to be an effective chemical model.

ChemInform Abstract: PREPARATION AND BAEYER‐VILLIGER REACTION OF CERTAIN 2‐CARBALKOXYCYCLOPROPYL METHYL KETONES

AbstractDer Carbobenzyloxycyclopropancarbonsäureester (I) bildet mit Äthylmagnesiumdi‐tert.‐butylmalonat (II) und anschließender Behandlung mit p‐Toluolsulfonsäure über (III) das Acetylcyclopropancarboxylat (IV).

5-phenyl-1,2,3,4-thiatriazole-3-oxide: A new class of heteroaromatic N-oxides

Oxidation of 5-phenyl-1,2,3,4-thiatriazole ( 1) with peroxytrifluoroacetic acid yields 5-phenyl-1,2,3,4-thiatriazole-3-oxide ( 2) a representative of a new class of heteroaromatic N-oxides. The structure is based on the mass spectral fragmentation of 2 and the isotope labelled with 15N at position 2. IR and ESCA measurements are consistent with this assignment. The thermal, photochemical, and chemical properties of the oxide are discussed.

Preparation and Baeyer‐Villiger Reaction of Certain 2‐Carbalkoxycyclopropyl Methyl Ketones

Treatment of mixed anhydrides derived from cis‐ and trans‐2‐carbobenzyloxycyclopropanecarboxylic acids and ethyl chloroformate with ethoxymagnesio di‐tert‐butyl malonate and subsequent treatment of the resulting adducts with p‐toluenesulfonic acid afforded cis‐ and trans‐benzyl 2‐acetylcyclopropanecar‐boxylates in good to excellent yields, with retention of the original stereochemistry of the systems. These methyl ketones and an open chain congener, benzyl levulinate, were inert toward m‐chloroper‐benzoic acid. The cis‐isomer and benzyl levulinate underwent normal Baeyer‐Villiger reactions mediated by trifluoroperacetic acid, forming moderate yields of the acetate ester insertion products.

On the synthesis of 3,4-dihydroxyprolines. II. Synthesis, stereochemistry and reactivity of some 3,4-Epoxy-DL-proline derivatives

N-Protected esters of 3,4-dehydro-DL-proline react with trifluoroperacetic acid to give, in high yield, approximately equal amounts of the corresponding stereoisomeric 3,4-epoxy-DL-proline derivatives, direct separation of which proved difficult. However individual members of the two families were obtained by discovery of selective transformations and fractionations. Relative configurations of the two 3,4-epoxy-N-tosylproline methyl esters were established by borohydride reduction to authentic 4-hydroxy-N-tosylprolinols. Epoxide reduction is regioselective. Extensive p.m.r. analyses then permitted stereochemical assignment of other derivatives. These epoxides are remarkably resistant to catalytic hydrogenolysis, and to hydration in acid or alkali. N-Substituted 3,4-epoxyproline methyl esters undergo ready β-elimination in alkali to yield the corresponding 4-hydroxy-2,3- dehydroproline esters and ultimately the N-substituted pyrrole-2- carboxylic acid or ester. Prolonged aqueous acid hydrolysis of 3,4- epoxy-N-tosylprolines, or of their methyl esters, gives mixtures of 3,4-dihydroxy-N-tosyl-DL-prolines in the 2,3-cis-3,4-trans and 2,3- trans-3,4-trans families. Their stereochemistry was allotted from p.m.r. of the diacetate methyl esters. During acid hydrolysis of 3,4- epoxy-N-tosylproline methyl esters, the ester of the trans stereoisomer hydrolyses selectively, and some epimerization of the cis stereoisomer occurs. Ester hydrolysis is much faster than epoxide hydration. Anhydrous acid cleavage of 3,4-epoxy-N-tosyl-DL-proline t-butyl esters to the epoxy acids is unusually slow.

Studies on the biosynthesis of β-lactam antibiotics. Part II. Synthesis, and incorporation into penicillin G, of (2RS,2′RS,3R,3′R)-[3,3′-3H2]cystine and (2RS,2′RS,3S,3′S)-[3,3′-3H2]cystine

n-Butyl glycidate with sodium phenylmethanethiolate gave 3-benzylthio-2-hydroxypropanoic acid (70%). In contrast, ethyl 2,3-epoxybutyrate underwent α-attack by phenylmethanethiolate yielding, after methylation, methyl 2-benzylthio-3-hydroxybutyrate (25%) and ethyl (benzylthio)acetate (70%). n-Butyl[cis-2,3-2H2]acrylate (synthesized by reduction with deuterium of n-butyl 9,10-dihydro-9,10-ethenoanthracene-11-carboxylate, followed by thermolysis of the [2H2]adduct) was epoxidised stereospecifically with trifluoroperacetic acid to yield n-butyl[cis-2,3-2H2]glycidate, which with phenylmethanethiolate gave, stereospecifically, DL-3-benzylthio-2-hydroxy[cis-2,3-2H2]propanoic acid. The analogous tritium compound, obtained similarly, was resolved via the brucine and quinine salts to afford the (2S,3S)-acid (7c) and the (2R,3R)-enantiomer (14). These were converted into the title compounds by bromination, treatment with ammonia to give the corresponding S-benzyl-cysteines, equilibration of the α-tritium atoms with acetic anhydride–acetic acid followed by acidic hydrolysis, and finally reduction with sodium–liquid ammonia and oxidation in air of the resultant (3R)- and (3S)-[3-3H]-cysteines.

The photochemistry of carbohydrate derivatives. Part IV. Photochemical rearrangement of 4,6-O-o-nitrobenzylideneglycopyranosides

Methanolic solutions of methyl 4,6-O-o-nitrobenzylideneglycopyranosides rearranged upon irradiation with u.v. light into mixtures of the corresponding amorphous glycopyranoside 4- and 6-o-nitrosobenzoates. Trifluoroperacetic acid converts these photoproducts into the corresponding 4- and 6-o-nitrobenzoates, which have been separated. The conditions used for this oxidation have been shown not to cause migration of the nitrobenzoyl groups.

Sulfur-free Penicillin Derivatives. VI. Synthesis of the 1-Oxacephem Ring System

The title compound has been synthesized by ring closure of an alkyl 2-(2′-chloro-3′-S-phthalimido-4′-oxo)azetidinyl-3-methyl-4-hydroxy-trans-2-butenoate using SN1 experimental conditions. The required E-allylic alcohols were obtained in two ways starting with an alkyl 2-(2′-chloro-3′-S-phthalimido-4′-oxo)azetidinyl-3-methyl-2-butenoate. The first involves allylic bromination with 1 molar equiv. of N-bromosuccinimide, conversion of the mixed Z- and E-allylic bromides into the mixed Z- and E-allylic formates, and deformylation to a mixture of E-alcohol and lactone. The alcohol was separated from the lactone via its tetrahydropyranyl derivative, and then regenerated. In the second route, allylic bromination was performed with 2 molar equiv. of N-bromosuccinimide and the resulting dibromo compound was converted into the β,γ-unsaturated olefin with zinc in acetic acid. Epoxidation with peroxytrifluoroacetic acid followed by exposure to triethylamine again afforded a mixture of E-alcohol and lactone. The u.v. spectrum of a 1-oxacephem shows a maximum at 266 nm.

Stepwise Photoreduction of (iso)Alloxazine N-Oxides in the Presence of 1,4-Cyclohexadiene

The direct synthesis of (iso)alloxazine N-oxides using trifluoroperacetic acid in situ is reinvestigated, showing sensitivity towards steric (peri) hindrance. The photoreduction of these N-oxides in the presence of 1,4-cyclohexadiene yields the parent (iso)alloxazine. The reduction of the N-oxides by initially formed dihydro (iso)alloxazine is ruled out for the photoreduction.