Diels-Alder reaction of tetraarylcyclopentadienones with benzo[b]thiophene S,S-dioxides: an unprecedented de-oxygenation vs. sulfur dioxide extrusion.

Diels-Alder reaction of tetraarylcyclopentadienones with benzo[b]thiophene dioxides in xylenes at reflux led to the formation of tetra aryl-substituted dibenzothiophene as well as penta aryl-substituted benzene analogues depending on the influence of aryl substituents present on cyclopentadienones. The intermediate dihydrodibenzothiophene-dioxides underwent aromatization either through de-oxygenation or extrusion of sulfur dioxide to furnish substituted dibenzothiophenes or benzenes.

Divergent Synthesis and Evaluation of the in†vitro Cytotoxicity Profiles of 3,4-Ethylenedioxythiophenyl-2-propen-1-one Analogues.

A new series of 3,4-ethylenedioxythiophene (EDOT)-appended propenones were prepared by condensation reaction and their in vitro cytotoxicity effects were evaluated against five human cancer cell lines. Preliminary structure-activity relationships of EDOT-incorporated 2-propenone derivatives were also established. The EDOT-appended enones demonstrated significant cytotoxicity against human cancer cell lines. The most active analogue, (E)-3-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (3 p, GI50 =110 nm), severely inhibited the clonogenic potential of cancer cells, and induced cell-cycle arrest in the G2/M phase and caused an accumulation of HCT116 colon cancer cells with >4 N DNA content. Also, 3 p exhibited weak inhibition of the enzymatic activity of human topoisomerase I. Molecular docking studies indicated preferential binding of the compounds to the ATP-binding pocket of the human checkpoint 2 kinase (Chk2) catalytic domain, thus, identifying a novel diaryl 2-propenone chemotype for the development of potent inhibitors of Chk2.

Crystal structure of dimethyl 1-oxo-2,4-di-phenyl-1,2-dihydronaphthalene-2,3-di-carboxyl-ate.

In the title compound, C26H20O5, a 1,2-di-hydro-naphthalene derivative, the cyclo-hexa-1,3-diene ring of the 1,2-di-hydro-naphthalene ring system adopts a half-chair conformation. The mean plane of the 1,2-di-hydro-napthalene ring system makes dihedral angles of 86.23 (6) and 64.80 (7)° with two phenyl rings. The carbonyl O atom attached to the di-hydro-naphthalene ring system deviates from the mean plane of the 1,2-di-hydro-naphthalene ring system by 0.618 (1) Å. In the crystal, the mol-ecules are linked into layers parallel to the bc plane via two kinds of C-H⋯O inter-actions, one of which forms a C(10) chain motif running along the c-axis direction and the other forms an R22(6) ring motif. Adjacent layers are further connected by C-H⋯π and offset π-π inter-actions [centroid-centroid distance = 3.6318 (9) Å].

Diels-Alder Reaction of Isobenzofurans/Cyclopentadienones with Tetrathiafulvalene: Preparation of Naphthalene, Fluoranthene, and Fluorenone Derivatives.

Diels-Alder reaction of 1,3-diarylbenzo[c]furan/cyclopentadienone with TTF followed by triflic acid mediated cleavage of the resulting adducts led to the formation of the respective 1,4-diaryl substituted naphthalenes, fluoranthenes, and fluorenones. The photophysical properties of representative diaryl-substituted hydrocarbons are also reported.

Synthetic Utility of Arylmethylsulfones: Annulative π-Extension of Aromatics and Hetero-aromatics Involving Pd(0)-Catalyzed Heck Coupling Reactions.

A straightforward and general method for the synthesis of annulated thiophene, dibenzothiophene, and carbazoles analogues has been achieved involving alkylation of 2-bromo-1-(phenylsulfonylmethyl)arene/heteroarene with arylmethyl bromides/heteroarylmethyl bromides using t-BuOK as a base in DMF, followed by Pd(0)-mediated intramolecular Heck coupling in the presence of K2CO3 in DMF at 80-140 °C. The attractive feature of this protocol is that a wide variety of π-conjugated heterocycles could be readily accessed by an appropriate choice of arylmethylsulfones and benzylic bromides.

Synthetic transformation of 1,3-diarylisobenzofuran-DMAD adducts: a facile preparation of tri-substituted α-naphthols.

1,3-Diarylisobenzofuran-DMAD adducts upon reaction with BF3·OEt2 in DCM at room temperature underwent a regiospecific 1,2-aryl migration followed by the Krapcho decarboxylation to give tri-substituted α-naphthols in good yields.

Diels-Alder reaction of 1,3-diarylbenzo[c]furans with thiophene S,S-dioxide/indenone derivatives: a facile preparation of substituted dibenzothiophene S,S-dioxides and fluorenones.

One pot syntheses of substituted dibenzothiophene S,S-dioxides and fluorenones were successfully achieved by Diels-Alder reaction of benzo[c]furans with thiophene S,S-dioxides and indenones, respectively. Photophysical properties of representative seven- and nine-membered dibenzothiophene S,S-dioxide acenes were also reported.