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A regioselective Rh(III)-catalyzed C—H arylation of arenes with arylboronic acid pinacol esters is developed using N-pentafluorophenylbenzamide as directing group.

A series of chromeno[4,3-d]isoxazolo[5,4-b]pyridin-6-one derivatives were easily and efficiently synthesized by the reaction of 3-acyl-2H-chromen-2-ones with isoxazol-5-amine in acetic acid. Some synthesized compounds were evaluated for their antiproliferative properties in vitro against cancer cells, and these compounds were found to have some activities.

A facile metal-free synthetic method to construct 2-aminothiophene ethers by treating 2-ynals with thioamides in various alcohols.

The oxidative olefination of a broad array of arenes and heteroarenes with a variety of activated and unactivated olefins has be achieved via a rhodium(III)-catalyzed C–H activation reaction. The use of an N-pentafluorophenyl benzamide directing group is crucial for achieving catalytic turnovers in the presence of air as the sole oxidant without using a co-oxidant.

Tetramisole-mediated reaction of 2-substituted acetic acids (I) and (IV) and α,β-unsaturated ketimines (II) gives the title compounds in good to high yields and with excellent stereoselectivities.

Photoacoustic imaging (PAI) is an emerging whole-body imaging modality offering high spatial resolution, deep penetration and high contrast in vivo. Signals for PAI are generated from contrast agents, where the laser-generated optical energy is transferred to acoustic emissions and detected by an ultrasound transducer. A great deal of research over the past ten years has shown that near-infrared absorption nanomaterials such as organic dye-based nanoparticals, polymer-based nanoparticles, carbon-based nanomaterials and metallic nanomaterials are promising photoacoustic (PA) contrast agents, which can increase the imaging resolution, contrast and depth of detection. Hence, it is an attractive research field to develop new PA contrast agents. Herein, we reviewed this rapidly growing field and described the applications of nanomaterial-based PA contrast agents for biomedical imaging. Particular focus was given to organic near-infrared absorbing dyes including cyanine, porphyrin and boron-dipyrromethene derivatives.

The application of smart supramolecular nanosystems in biomedicine increases rapidly and offers promising prospects for disease diagnostics and therapeutics. Supramolecular nanosystems such as liposomes, micelles, organic nanoaggregates and metallic nanostructures etc. have been widely explored as diagnostic/therapeutic tools. Here, we review the recent advances in supramolecular nanosystems with different built-in reporters, e.g., fluorescent, magnetic and photoacoustic signals for bioimaging. In addition, the substantial progress of supramolecular nanosystems as drug delivery carriers for cancer therapy, including chemotherapy, photothermal and photodynamic therapies is also summarized.

isolation and structure elucidation of fourteen sesquiterpenoids including the novel terpenoids (I) and (II) and in vitro effects of twenty sesquiterpenoids on AChE activity

A one-pot isothiourea-mediated Michael addition/lactonization/thiol elimination cascade sequence for the formation of 4,6-disubstituted and 3,4,6-trisubstituted 2-pyrones from (phenylthio)acetic acids and α,β-unsaturated trifluoromethyl ketones is described. The synthesis of a COX-2 inhibitor and the wide-ranging derivatization of the 2-pyrone moiety to trifluoromethyl substituted aromatics and heteroaromatics is also disclosed.

The reaction of a range of α,β-unsaturated ketimines with (phenylthio)acetic acid in the presence of an isothiourea catalyst is developed to yield 2,4,6-trisubstituted pyridines.

A porous crystalline TiO2 with heavily self-doped Ti3+ species is prepared by solid state reaction of a porous amorphous TiO2 precursor and urea (N2 atmosphere, 700 °C, 10 h).

Condensation of the zinc salt, formed in nearly quantitative manner, with indoline bases (I) in the presence of cyclic amines affords the title compounds in moderate to good yields.

We have previously reported that reaction of guanosine or 2′-deoxyguanosine with trifluoroacetic anhydride in pyridine gives a putative 6-pyridyl intermediate from which several 6-substituted derivatives may be obtained.1 We now report high-yield conversion of guanosine and 2′-deoxyguanosine to the corresponding 6-thio compounds in a two-step, one-flask reaction via this 6-pyridyl intermediate. Standard Raney nickel treatment, as reported for the ribonucleoside,2 then gives the 2-aminopurine nucleosides.

The 6-O-(pentafluorophenyl)-2'-deoxyguanosine derivative 2a can be used to generate in high yield 6-O-methyl-2'-deoxoguanosine, 2,6-diamino-9-(2-deoxy-β-D-erythro-pentofuranosyl)purine, and related derivatives. Further, after appropriate protection and derivatization, 2a can be incorporated into oligonucleotides and there used for postsynthetic oligonucleotide modification. This approach is particularly useful for preparation of oligonucleotides containg 2,6-diaminopurine residues or their 6-alkylamino derivatives. In addition, reaction of 2a, or oligonucleotides containing it, with 4-(dimethylamino)pyridine (DMAP) gives a fluorescent guanine-DMAP adduct

DNA synthesis by H-phosphonate method does not require the use of amino protecting groups. The cytosine amino group, and the guanine 06/N1 positions, do react with the condensing agent to some extent, but these derivatives are cleaved under the standard aqueous ammonia conditions commonly used for deproctection and cleavage of the oligonucleotide from the solid support.

A robust, regioselective synthesis of 3-amino-1,2,4-triazoles is described. This reaction employs a key intermediate 2, which is coupled to carboxylic acids in good yields to afford intermediates 3a–d. These entities, in turn, react with a variety of hydrazines or hydrazine hydrochlorides to provide proposed intermediates 4a–j, which under microwave conditions cyclize to the desired 3-amino-1,2,4-triazoles (compounds 5a–j). This approach permits the rapid synthesis of regioselective N1-substituted 3-amino-1,2,4-triazoles, and is shown to afford a variety of such compounds in 34–70% isolated yields.

tract - A facile synthesis of rolipram via stepwise [3+2] annulation and desulfonated hydrolysis was reported. Base-induced coupling/cyclization reactions of α-sulfonylacetamide with (Z)-2-bromoacrylic ester yielded threecontiguous centers on the pyroglutamate system with trans-trans orientation as the one-pot key step.

A facile synthesis of 3-aryl pyroglutamic acids via stepwise [3+2] annulation and desulfonated hydrolysis is reported. Base-induced coupling/cyclization reactions of α-sulfonylacetamide with various β-functional groups of ( Z )-2-bromoacrylates yielded three contiguous chiral centers on the polysubstituted pyroglutamates system with trans – trans orientation in a one-pot synthesis. This facile strategy was used to synthesize amino acid derivatives baclofen and chlorpheg.

Ozonides derived from terminal alkenes reacted with 1.3 mol equiv. of stable phosphonium ylides to give ( E )-α,β-unsaturated carbonyl compounds in good to excellent yields. No reducing agent is needed in the reaction. However, alkoxyalkyl-substituted ozonides afforded a mixture of ( Z )- and ( E )-α,β-unsaturated carbonyl compounds under similar condition. The E / Z isomeric ratio is affected by the position of the heteroatom in the substituent of the ozonides. The possible mechanism of this reaction will be discussed.