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Dodecahydrotriphenylene, a higher homologue of trindane chemoselectively undergoes unidirectional benzylic sp3 C–H oxidation and the central benzene ring remains intact unlike that in trindane under similar reaction conditions. RuO4 which generally attacks sp2 C–H to form oxidative products is found to give benzylic ketones via sp3 C–H oxidation. Density functional theory (DFT) calculations have also been performed to analyse the potential energy, energy barrier and HOMO–LUMO energy gap of the products.

Bisphenols, generally formed by condensation of phenols with carbonyl compounds, have found several useful applications. 1–7 The literature records a number of methods for synthesis of bisphenols u...

The bulky-headed oxidant hexadecyltrimethylammonium periodate affords the diastereomeric pairs, (Ss)-(+)/(Rs)-(+) and (Ss)-(−)/(Rs)-(−)-neomenthyl phenyl sulfoxides in stereochemically pure states with improved diastereomeric excess (48% diastereomeric excess [de]) as compared to its nonbulky counterpart, sodium metaperiodate (28% de) from respective (+)/(−)-neomenthyl phenyl sulfides. Steric effects involving the head group volume of hexadecyltrimethylammonium periodate is found to play a role in improving the diastereomeric ratio of the products. The two diastereomers can be readily separated by column chromatography. Absolute configuration at the sulfur center in (+)-neomenthyl phenyl sulfoxide was determined by single-crystal X-ray crystallography and found to be Ss. Relative configurations of other sulfoxides were assigned based on the configuration of (+)-neomenthyl phenyl sulfoxide. Chirality 27:370–374, 2015. © 2015 Wiley Periodicals, Inc.

A one-pot synthesis of 3,4-dihydro-3-hydroxyisochroman-1-one (lactol) 3 by oxidation of indene using tungstic acid-hydrogen peroxide is reported. The synthesized lactol was converted into acetal derivatives 5a–h, which were evaluated for their in vitro antibacterial activity against Staphylococcus aureus, Streptococcus pyogenes (Gram-positive), Escherichia coli, Pseudomonas aeruginosa (Gram-negative) strains, and antifungal activity against Candida albicans and Aspergillus niger by broth dilution method. The compounds show potent activity against S. aureus in comparison with ampicillin and exhibit modest antifungal activity.

A novel approach for the synthesis of a bird-shaped bis-triquinane 3, a fascinating carbocyclic framework closely related to the skeleton of Xeromphalinone E 1 from readily available 2,6-dimethyl phenol 8 has been reported. The synthesis of bis-cyclohexadienones 6, 22a–e by oxidative acetylation of tetramethyl bisphenols 7, 20a–e has been investigated using two different reagents under varying reaction conditions. The cycloaddition of bis-cyclohexadienone 6 gives two carbocycles, bis-adduct 4b and mono-adduct 5d in a stereocontrolled manner. The photochemical sigmatropic 1,2-acyl shift in 4b furnished 3 and monotriquinane 9 linked with a 9-acetoxy-9-methyl-endo-tricyclo[5,2,2,02,6]undeca-4,10-diene-8-one system. Two different pentasubstituted phenols 13 and 14 were also isolated during an attempted oxa-di-π-methane (ODPM) rearrangement of mono-adduct 5d via aromatisation of the cyclohexadienone ring. The photochemical behaviour of bis-cyclohexadienones 6, 22a–e has also been investigated under UV irradiation and two different aromatized products were isolated for each bis-cyclohexadienone by migration and elimination of acetate groups.

Tungstic acid was used as a low-cost and readily available heterogeneous catalyst for the synthesis of 3,3-bis(1H-indol-3-yl)indolin-2-one derivatives from indoles. The reaction parameters, including catalyst quantity, solvents, temperature, and time were optimized. The present method has several advantages, such as mild conditions, simple work-up, elimination of anhydrous condition, easy recovery of catalyst and its recyclability as compared with existing methods.

Syntheses of novel carbocycles (4) and (5) based on cycloaddition of bis-cyclohexa-2,4-dienone (3) and cyclopentadiene is reported. An improved method for the preparation of tetramethyl bisphenol-F (2), a precursor of bis-cyclohexa-2,4-dienone (3), is also presented.

The first synthesis of the bird-shaped bis-triquinane 7, possessing a fascinating molecular architecture from readily available materials 2,6-dimethyl phenol and cyclopentadiene has been reported. Pentasubstituted phenols 9 and 10 were isolated during attempted photochemical oxa di-π methane rearrangement of acetic acid 3-(9-acetoxy-7,9-dimethyl-8-oxo-3a,4,7,7a-tetrahydro-1H-4,7-ethano-inden-5-ylmethyl)-1,5-dimethyl-6-oxo-cyclohexa-2,4-dienylester 4, a fused bicyclic system connected with a 2,4-cyclohexadienone unit. A probable mechanism is proposed for aromatisation.

An unexpected behaviour of compilation of reagent sodium metaperiodate in acetic anhydride for acetylation of bisphenols was observed during attempted oxidative acetylation of bisphenols for the synthesis of a bis-acetoxy cyclohexadienone. The products were characterized by their spectral and analytical data and a probable mechanism for acetylation involving role of NaIO 4 is proposed.

Oxidative acetylation of tetramethyl bisphenol‐F (2) using two different reagents is described. The reaction of (2) with NaIO4 in acetic anhydride furnished a novel triacetate (3) and its reaction with lead tetraacetate (LTA) in dry benzene resulted in the formation of a novel bis‐cyclohexadienone (4).

A new, simple, one‐pot method for the oxidative acetylation of some substituted phenols leading to acetoxycyclohexa‐2,4‐dienones is described. A novel diacetoxycyclohexadienone 12 has also been pre...

The effect of photostabilization of azadirachtin-A (Aza-A) was examined in solutions when exposed to UV radiation, in the presence of four structurally different UV absorbers namely, p -aminobenzoic acid, 2,4-dihydroxybenzophenone, 4,4'-dihydroxybenzophenone and phenyl salicylate. The percentages of Aza-A recovered from the solutions after 6 h exposed to UV radiation in the presence and absence of UV absorbers indicated that the order of stabilization of Aza-A by these absorbers was similar to that obtained in the solid phase experiments in accordance with our previous observations. It is observed that the addition of phenyl salicylate in Aza-A (in 1 : 1 mole ratio) provides the excellent photostabilization of Aza-A molecule in solid phase as well as in solution among the four absorbers studied.

This describes attempts to synthesize compound (I), which is structurally related to Xeromphalinone E.

Treatment of bisphenols with NaIO4 in acetic anhydride provides unexpected acetylated products instead of bis-acetoxy cyclohexadienone derivatives.

C32 cages built from four-, five-, six-, and seven-membered rings are computed. The computations are primarily performed with semiempirical quantum-chemical methods (AM1, PM3, SAM1), and altogether 199 cages are optimized. The energetics is further checked through ab initio HF SCF computations with the standard 3-21G basis set, and also by density functional theory at the B3LYP level in the standard 6-31G∗ basis set. All five levels of theory suggest a D4d cage (two four-membered rings, eight pentagons, eight hexagons) as the lowest-energy structure. Temperature effects are treated in the terms of partition functions so that the entropy contributions are considered accordingly. The thermodynamic treatment points out five cages significantly populated at high temperatures. At very high temperatures the structure lowest in energy is not the most abundant isomer. There are just six conventional fullerenes C32, built exclusively from pentagons and hexagons, however, only two of them show significant ...

In the absence of a reactive alkene, the Diels-Alder dimer of 2,6-dimethyl-6-hydroxycyclohexa-2,4-dienone rearranges at 160 °C to a new dimer via a reverse Diels-Alder reaction, two α-hydroxyketone rearrangements, two Micheal additions, and two aldol condensations. © 1997 Elsevier Science Ltd.

A short, new and general approach for the synthesis of linear polyquinanes having the cis:anti:cis tricyclopentanoidal framework is delineated. The key element of this approach is the photochemical 1,2-acyl shift or oxa-di-π-methane rearrangement of annulated bicyclo[2.2.2]octenones, having β,γ-unsaturated carbonyl chromophoric systems. An efficient method for the synthesis of a variety of annulated bicyclo[2.2.2]octenones via inverse demand π4s+π2s cycloaddition of cyclohexa-2,4-dienones (9-12) with olefins (18-26) is reported. The structure of the adducts has been established through the study of their high-field 1H NMR and 13C NMR spectra and decoupling experiments. Synthesis of tricyclo[5.2.2.02,6]undecadienones (51-57) from readily available adduct 43 has been achieved. Oxa-di-π-methane rearrangement of various chromophoric systems to polyquinanes (60-68) is described. The adduct 32 did not undergo oxa-di-π-methane rearrangement upon sensitized irradiation, while adduct 40 rearranged inefficiently to compound 64. Studies on the cleavage of the cyclopropane ring of the tetracyclic ketones (60, 66, 67 and 73) with formic acid and acetyl methanesulfonate is also reported.

Oxidative acetylation of tetramethyl bisphenol‐F (2) using two different reagents is described. The reaction of (2) with NaIO4 in acetic anhydride furnished a novel triacetate (3) and its reaction with lead tetraacetate (LTA) in dry benzene resulted in the formation of a novel bis‐cyclohexadienone (4).

A new, simple, one‐pot method for the oxidative acetylation of some substituted phenols leading to acetoxycyclohexa‐2,4‐dienones is described. A novel diacetoxycyclohexadienone 12 has also been pre...

Azadirachtin-A (Aza-A, figure 1) was subjected to a variety of synthetic transformations and the antifeedant activity and toxicity of the azadirachtin derivatives were assessed against second instar larvae Spodoptera litura on castor leaves in comparison with the crude material containing 9.14% Aza-A, as well as relatively pure 91% Aza-A. A probable mechanism for the base initiated fragmentation of the diketocarbonate into a decalin fragment and a spiroketal moiety has been proposed. The present study indicates that the combination of insect toxicity and antifeedancy of azadirachtin provides good crop protection.

(1993). AN IMPROVED PROCEDURE FOR THE PREPARATION OF 1,6-DICARBOXYHEX-3-ENE. Organic Preparations and Procedures International: Vol. 25, No. 5, pp. 579-581.

In the absence of a reactive alkene, the Diels-Alder dimer of 2,6-dimethyl-6-hydroxycyclohexa-2,4-dienone rearranges at 160 °C to a new dimer via a reverse Diels-Alder reaction, two α-hydroxyketone rearrangements, two Micheal additions, and two aldol condensations. © 1997 Elsevier Science Ltd.

The reaction of endo-dicyclopentadiene 1 with tungstic acid–hydrogen peroxide in 2-methylpropan-2-ol to form the polycyclic compounds 2 and 3 is reported, and a plausible mechanism for the formation of these products is discussed.

A short synthesis of various tricyclo(5.2.2.02 6) undecadienones by Diels-Alder reaction of a 2,4-cyclohexadienone with dienes and their oxa-di π- rearrangement is reported.

A simple synthesis of spirodiones (2)&(3) via n6s+ n2s photocyclization of the Deils-Alder adducts (4)&(5) obtained by reactions of spiro (4,2) heptadiene (6) and spiro (4,4) nonadiene (7) with 1,4- naphtho-quinone in homogeneous and micellar media. A remarkable catalytic effect by micelle on cycloaddition is noted.

Micelle catalyzed Diels-Alder reaction of cyclic dienes with various quinones in aqueous media is described. Micellar cycloadditions are remarkably faster and give better yields of the adducts compared to the conventional reaction.

An efficient synthesis of the title compound by Diels-Alder cycloaddition of spiro(4.2) heptadiene with p-benzoquinone followed by photochemical ring closure is described.

An efficient synthesis of the title compound by Diels-Alder cycloaddition of spiro (4.4) nonadiene with p-benzoquinone followed by photochemical ring closure is described.

A convenient synthesis of (Z) cyclooct-5-enetrans-1, 2-diol from oxidation of cycloocta-1, 5-diene with H2WO4-H202 is described. The trans-1, 2-diol is further transformed into 1, 6-dicarbomethoxy (Z) hex-3-ene.

An efficient synthesis of the title compound by Diels-Alder cycloaddition of spiro(4.2) heptadiene with p-benzoquinone followed by photochemical ring closure is described.

An efficient synthesis of the title compound by Diels-Alder cycloaddition of spiro (4.4) nonadiene with p-benzoquinone followed by photochemical ring closure is described.

A simple synthesis of spirodiones (2)&(3) via n6s+ n2s photocyclization of the Deils-Alder adducts (4)&(5) obtained by reactions of spiro (4,2) heptadiene (6) and spiro (4,4) nonadiene (7) with 1,4- naphtho-quinone in homogeneous and micellar media. A remarkable catalytic effect by micelle on cycloaddition is noted.

A short synthesis of various tricyclo(5.2.2.02 6) undecadienones by Diels-Alder reaction of a 2,4-cyclohexadienone with dienes and their oxa-di π- rearrangement is reported.