Indra Prakash

An Improved Synthesis of Ethyl Azodicarboxylate and 1,2,4-Triazoline-3,5-Diones Using Hypervalent Iodine Oxidation

Abstract ARSTRACT: Hypervalent iodine oxidstion of 1,2-dicarhethoxy hydrazine (1) and 4-substituted urazoles (3) using iodobenzene diacetate or pentafluoroiodobenzene bis-trifluoroacetate in CH2Cl2 at room temperature proceeds smoothly to yield ethyl azodicarboxylate (2) and 4-substituted 1,2,4-triazoline-3,5-diones (4) in excellent yields.

OXYGEN REQUIREMENT FOR NEAR-UV MEDIATED CYTOTOXICITY OF PHENYLHEPTATRIYNE TO Escherichia coli

Abstract— Phenylheptatriyne (PHT) is a good singlet oxygen sensitizer in vitro. In vivo, its phototoxicity toward E. coli B has been proved unequivocally to depend on the presence of oxygen. The literature reports indicating that phenylheptatriyne was representative of a new class of sensitizers were probably based on experiments conducted under conditions which were not strictly anaerobic.

Steric effects in the hypervalent iodine oxidation of ketones

Abstract Oxidation of 3-cholestanone (1) with C 6 H 5 I(OAc) 2 or o-OIC 6 H 4 COOH or C 6 H 5 IO 2 in KOH/MeOH yields 2 α-carbomethoxy-A-norcholestane (2). This result is interpreted on mechanistic grounds and compared with the course of the reaction with other sterically hindered ketones such as friedelin, 3-keto, 12-keto, 17-keto steroids, and 2,2,6,6-tetramethyl-4-piperidone.

α-Hydroxydimethylacetal formation from aminoketones using hypervalent iodine

Abstract Various β-aminoketones were converted into the α-hydroxydimethylacetal using either o-iodosylbenzoic acid or (diacetoxy) iodobenzene (KOH/CH3OH) without oxidation at 1°, 2° or 3°, amino groups or at sulfur in the case of a morpholino group.

Possible role of Lewis acid catalysis in the oxidation of alkenes and α,β-unsaturated ketones using bleomycin-Zn(II) and bleomycin-Fe(III)-iodosylbenzene in aqueous methanol

Abstract C6H5IO in CH3OH-H20 is activated towards electrophilic attack upon various alkenes by Fe(ClO4).9H2O, FE(III) bleomycin and ZN(II) bleomycin. The results imply that direct transfer of oxygen from an Fe(V)=0 intermediate is not required in the mechanism of oxygenation by iron-containing species, and that much earlier work is questionable as models for biological oxygenation.

Synthesis of 1,4-diketones by the coupling reaction of trimethylsilyl enol ethers with lead tetraacetate

Abstract Synthesis of 1,4-diketones in good yields was achieved by the coupling reaction of the trimethylsilyl enol ethers of acetophenone, thiophene or furan with lead tetraacetate in dry dichloromethane and tetrahydrofuran at −78°C.

Novel pentafluorophenyl hypervalent iodine reagents

Abstract The novel C 6 F 5 I(OH)OTs has been synthesized and shown to undergo ligand exchange with C 6 H 5 I, iodonium ylide formation with dimedone and iodonium salt formation with anisole.

Mild carbon–carbon bond cleavage of carbonyl compounds using pentafluoroiodobenzene bis(trifluoroacetate)

Acetophenones, α-hydroxyacetophenones, deoxybenzoin, benzoin, and benzil are cleaved oxidatively with pentafluoroiodobenzene bis-(trifluoroacetate) in wet benzene at room temperature to give the corresponding benzoic acids; cyclohexanone and dimedone are cleaved to give the diacids adipic acid and 3,3-dimethylglutaric acid, respectively.

α-Methoxy Ketones by the Reaction of Trimethylsilyl Enol Ethers with Lead Tftraacetate in Methanol

Abstract Trimethylsily1 enol ethers of acetophenone, 2-acetylthiophene and 2-acetylfuran react with lead tetraacetate in methanol at room temperature to give the α-methoxy ketones in good yields.

Intramolecular participation in hypervalent iodine oxidation. The synthesis of coumaran-3-ones, aurone, and isoaurone

Oxidation of o-hydroxyphenyl alkyl ketones with Phl(OAc)2/KOH–MeOH leads to 2,2-dimethoxycoumaran-3-ones which in the case of o-hydroxy-α-phenylpropiophenone offers a convenient route to aurone and isoaurone.