Reactions promoted by [hydroxy(tosyloxy)iodo]benzene in pyrazino[1,2-b]isoquinolines

The hypervalent iodine reagent PhI(OH)OTs (HTIB) promoted oxidative demethylation of 1,4-hydroquinone methyl ethers to give quinones in a quantitative conversion. The efficacy of this reaction, that has been applied to simple arene compounds and to heterocyclic systems, such as 2-isopropoxycarbonyl-7,10-dimethoxy-pyrazino[1,2-b]isoquinoline-4-ones and 1,4-diones to get the corresponding 7,10-quinones (compounds 6-8), is similar to those promoted by CAN and does not require the presence of water. Instead of oxidative demethylation, HTIB promoted in 1-methoxy-pyrazino[1,2-b]isoquinoline-4-ones complex multi-step processes to give compounds 9 or 10.     

Synthesis of isoxazoline N-oxides via [hydroxy(tosyloxy)iodo]benzene (HTIB)-mediated oxidative N-O coupling

An HTIB mediated oxidative N-O coupling strategy for the synthesis of some isoxazoline N-oxide derivatives from β-hydroxyketoximes is described, along with a comparative study of the efficiency of N-O coupling in two different solvents. A plausible mechanism for the conversion is proposed.     

A Facile [hydroxy(tosyloxy)iodo]benzene Mediated Synthesis of Symmetrical Triazolo-[3,4-b]-1,3,4-Thiadiazines

Synthesis of the title compounds has been accomplished by a one-pot procedure involving the reaction of 3-substituted-4-amino-5-mercapto-1,2,4-triazoles and a variety of heterocyclic ketones in the presence of [hydroxy(tosyloxy)iodo]benzene.     

Solvent-free facile synthesis of novel α-tosyloxy β-keto sulfones using [hydroxy(tosyloxy)iodo]benzene

A facile, general and high yielding protocol for the synthesis of novel α-tosyloxy β-keto sulfones is described utilizing relatively non-toxic, [hydroxy(tosyloxy)iodo]benzene, under solvent-free conditions at room temperature.     

Efficient oxidation of benzylic alcohols with [hydroxy(tosyloxy)iodo]benzene under microwave irradiation

An efficient method for the oxidation of benzylic alcohols with [hydroxy(tosyloxy)iodo]benzene under solvent-free microwave irradiation conditions is described.     

Reactivities of novel [hydroxy(tosyloxy)iodo]arenes and [hydroxy(phosphoryloxy)iodo]arenes for alpha-tosyloxylation and alpha-phosphoryloxylation of ketones

Novel [hydroxy(tosyloxy)iodo]arenes bearing 2-thienyl, 3-thienyl, N-tosyl-4-pyrazolyl, 3-trifluoromethylphenyl, and 3,5-bis(trifluoromethy)phenyl as an aromatic group, and [hydroxy(phosphoryloxy)iodo]arenes bearing N-tosyl-4-pyrazolyl, 3-trifluoromethylphenyl, and 3,5-bis(trifluoromethy)phenyl as an aromatic group, were prepared. alpha-Tosyloxylation and alpha-phosphoryloxylation of ketones with these compounds were carried out, respectively. Their reactivities were compared with that of the parent [hydroxy(tosyloxy)iodo]benzene and [hydroxy(phosphoryloxy)iodo]benzene, respectively, and consequently [hydroxy(tosyloxy)iodo]arenes and [hydroxy(phosphoryloxy)iodo]arenes bearing 3-trifluoromethylphenyl and 3,5-bis(trifluoromethy)phenyl as an aromatic group showed the best reactivity. These new compounds can be used as powerful alpha-tosyloxylation and alpha-phosphoryloxylation reagents, instead of the parent [hydroxy(tosyloxy)iodo]benzene and [hydroxy(phosphoryloxy)iodo]benzene.     

A novel one-pot synthesis of 3-carbomethoxy-4-arylfuran-2-(5H)-ones from ketones using [hydroxy(tosyloxy)iodo]benzene

A novel one-pot procedure for the synthesis of 3-carbomethoxy-4-aryl furan-2-(5H)-ones is reported via α-tosyloxylation of enolisable ketones with [hydroxy(tosyloxy)iodo]benzene, followed by treatment with potassium monomethyl malonate and K₂CO₃.     

A Convenient Synthesis of 4-(2-Furyl)-2-substituted Thiazoles Utilising [Hydroxy(tosyloxy)iodo]benzene

A facile synthesis of 4-(2-furyl)-2-substituted thiazoles by hypervalent iodine oxidation of 2-acetylfuran (1) using [hydroxy(tosy-loxy)iodo]benzene, followed by treatment of the reaction mixture with appropriate thioureas/thioamides is described.     

Application of [hydroxy(tosyloxy)iodo]benzene in the Wittig-ring expansion sequence for the synthesis of beta-benzocyclo-alkenones from alpha-benzocycloalkenones

The conversion of alpha-benzocycloalkenones to homologous beta-benzocyclo-alkenones containing six, seven and eight-membered rings is reported. This was accomplished via a Wittig olefination-oxidative rearrangement sequence using[hydroxy(tosyloxy)iodo]-benzene (HTIB) is the oxidant, that enables the synthesis of regioisomeric pairs of methyl-substituted beta-benzocycloalkenones. The incorporation of carbon-13 at C-1 of the beta-tetralone nucleus was also demonstrated. The Wittig-HTIB approach is a useful alternative to analogous sequences in which Tl(NO3)3.3H2O or the Prevost combination (AgNO3/I2) are employed in the oxidation step.     

Hydroxy(tosyloxy)iodo]benzene mediated alpha-azidation of ketones

Reaction of various ketones with [hydroxy(tosyloxy)iodo]benzene (HTIB) followed by treatment of the alpha-tosyloxy ketones thus generated in situ with NaN3 offers a one-pot procedure for the synthesis of alpha-azido ketones. The HTIB used in this conversion may also be generated in situ by using iodosobenzene in combination with p-toluene-sulphonic acid.     

Novel preparation of 2,1-benzothiazine derivatives from sulfonamides with [hydroxy(tosyloxy)iodo]arenes

Cyclization of sulfonamides bearing an aromatic ring at the beta-position with various organohypervalent iodine compounds was carried out to form the corresponding 2,1-benzothiazine derivatives. Among them, the cyclization effectively proceeded with [hydroxy(tosyloxy)iodo]arenes through ionic pathways. The same treatment of a sulfonamide bearing a 4-methoxyphenyl group at the beta-position generated a spiro compound.     

A novel and convenient approach for tosyloxylation of aromatic ring of some ortho-substituted phenolic compounds using [hydroxy(tosyloxy)iodo]benzene

The oxidation of some substituted monohydric phenols, containing electron-withdrawing substituents at the ortho position to the phenolic group, with [hydroxy(tosyloxy)iodo]benzene (HTIB, Koser’s reagent) leads to novel tosyloxylation of aromatic ring, thereby offering a convenient synthesis of hitherto unknown 4-tosyloxy-2-substituted phenols.     

Synthesis of Flavones from the Hypervalent Iodine Oxidation of Flavanones Using [Hydroxy(tosyloxy)iodo]benzene in Methanol

Hypervalent iodine oxidation of several flavanones (1a-1f) using (hydroxy(tosyloxy)iodo] benzene in methanol offers a new method for the synthesis of flavones (2a-2f).     

[Hydroxy(tosyloxy)iodo]benzene as Thermal initiator for the Radical Polymerization of Methyl Methacrylate

Abstract

The thermal polymerization of methyl methacrylate in a solution of N,N-dimethylacetamide has been studied using [hydroxy(tosyloxy)- iodo]benzene (HTIB) as the initiator. The rate of polymerization was a direct function of the monomer and initiator concentrations. The initiator and monomer exponent values expressing this dependence were found to be 1.0 and 0.8, respectively. The overall activation energy of polymerization was estimated to be 45 kJ·mol^?-1. The polymerization was inhibited in the presence of hydroquinone. The effect of various solvents on the polymerization rate was studied. The polymer prepared with HTIB (0.47 × 10^?3 mol·L^?-1) had a number-average molecular weight of 138,000 and a glass transition temperature of 106°C. The polymer showed good thermal stability as determined by thermogravimetric analysis.     

Use of [hydroxy(tosyloxy)iodo]benzene in a novel and facile synthesis of 1,4-diaryl-2-(arylamino)but-2-ene-1,4-diones

The reaction of acetophenones 1 with [hydroxy(tosyloxy)iodo]benzene followed by treatment of the resulting α-tosyloxyacetophenones 2 thus formed with anilines 3 in the presence of sodium carbonate in ethanol provides a novel one-pot synthesis of 1,4-diaryl-2-(arylamino)but-2-ene-1,4-diones 4.     

Hypervalent Iodine in Synthesis XXIII: Oxidation with [Hydroxy(tosyloxy)iodo]benzene: Selective Oxidation of Sulfides to Sulfoxides

Alkyl-and aryl-sulfides can be selectively oxidated to their corresponding sulfoxides with excellent yields under mild conditions by [hydroxy (tosyloxy)iodo]benzene. Morever, [hydroxy (((+)-10-camphorosulfonyl)oxy)iodo]benzene as the chiral oxidizer, can be used to oxidate unsymmetric sulfides to sulfoxides with a few %ee to some extent.