Jayachandran Karunakaran

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.

Fracture resistance of teeth restored with cast post and core: An in vitro study.

Context: Influence of luting agent, design of tooth preparation for cast posts on tooth resistance to fracture. Aim: To evaluate fracture resistance of teeth restored with cast posts and cores with or without cervical ferrule and cemented with zinc phosphate, glass ionomer, or resin cement. Materials and Methods: Sixty single-rooted maxillary first premolars of similar sizes were selected. Biomechanical preparation and post space preparation for cast post was done for all samples and then they were divided into two groups (n=30). Cervical ferrule preparation was done for Group A, and Group B was prepared without any cervical ferrule. Both groups were further divided into three subgroups (1, 2, and 3; n=10) Cast posts for subgroups 1, 2, and 3 were cemented with zinc phosphate, glass ionomer, and resin cement, respectively. A shearing load was applied to indented buccal cusp of specimens at an angle of 45° in universal testing machine at a cross-head speed of 1 mm/min until fracture. Results: Specimens with ferrule (Group A) had significantly higher shear bond strength values (mean 1503.37 N) than specimens without ferrule (Group B) (mean 1052.09 N). Conclusion: Inclusion of ferrule in tooth preparations for posts increased the fracture resistance regardless of the luting agent.

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.

Oxidative cleavage of 1,3-diaryl/(heteroaryl)benzo[c]furans into 1,2-diaroyl/(heteroaroyl)benzenes using selenium dioxide

ABSTRACT Reaction of 1,3-disubstituted isobenzofurans (IBFs) with selenium dioxide in tetrahydrofuran (THF) at room temperature led to the formation of 1,2-diaroyl/(heteroaroyl)benzenes in good to excellent yields. GRAPHICAL ABSTRACT

Management of invasive cervical resorption in a maxillary central incisor

Invasive cervical resorption is often not diagnosed properly, leading to improper treatment or unnecessary loss of the tooth structure. Early diagnosis and appropriate treatment are the keys to a successful outcome of therapy. Invasive cervical resorption is often seen in the cervical area of the tooth, but because it is initiated apical to the epithelial attachment, it can present anywhere in the root. In the early stages, it may be symmetrical, but larger lesions have the tendency to be asymmetrical. It can expand apically or coronally.

Crystal structure and Hirshfeld surface analysis and energy frameworks of 1-(2,4-di­methyl­phen­yl)-4-(4-meth­oxy­phen­yl)naphthalene

In the title naphthalene derivative, the mean plane of the naphthalene ring system makes dihedral angles of 65.24 (12)° with the dimethylphenyl ring and 55.82 (12)° with methoxyphenyl ring. The latter two rings are inclined to each other by 59.28 (14)°.

Crystal structure of dimethyl 1-oxo-2,4-di­phenyl-1,2-dihydronaphthalene-2,3-di­carboxyl­ate

In the title compound, a naphthalene derivative, the cyclohexa-1,3-diene ring of the 1,2-dihydronaphthalene ring system adopts a half-chair conformation. The mean plane of the 1,2-dihydronapthalene ring system make dihedral angles of 86.23 (6) and 64.80 (7)° with two phenyl rings. In the crystal, the molecules are linked by C—H⋯O, interactions and further stabilized by C—H⋯π and π–π interactions.

A comparative evaluation of intraradicular smear removal efficacy of 2% chitosan (low molecular weight), 4% Chitosan Citrate, and 10% Citric Acid when Used as Final Rinse in Irrigation Protocols: A Field Emission Scanning Electron Microscopic Study

Aim: This study aims to compare the smear layer removal efficacy of 2% chitosan (low molecular weight) (C-LMV), 4% chitosan citrate (CC), and 10% citric acid (CA) when used in specific irrigant protocols. Materials and Methods: A total of 60 single-rooted maxillary incisors and canines were decoronated, standardized to a root length of 15 mm, and prepared with rotary files up to protaper F3 size. Sodium hypochlorite was used as initial rinse [8 ml]. The samples were divided into experimental (Group III, IV, V, and VI) (n = 10) and control groups (I – 17% EDTA, II – normal saline) (n = 5) based on the type of final rinse solution (5 ml) used, that is, 2% C-LMV, 4% C-citrate, 10% CA, and 1% acetic acid. Samples were dehydrated, split buccolingually, gold sputter coated, and examined in field emission scanning electron microscope. Results: Overall, the Group IV, V, and III presented the least amounts of smear, debris, and erosion among the experimental groups at the apical, middle, and coronal one-thirds of the root canal with a mean value of 1.53 ± 0.42, 1.33 ± 0.42, and 1.60 ± 0.46, respectively, and there was no statistically significant difference (P > 0.05). Conclusion: The use of CC as final rinse solution during biomechanical preparation seems promising.