Synthesis and structure–activity relationship of 1H-indole-3-carboxylic acid pyridine-3-ylamides: A novel series of 5-HT2C receptor antagonists

The Recycling of Substandard Rocket Fuel N,N-Dimethylhydrazine via the Involvement of Its Hydrazones Derived from Glyoxal, Acrolein, Metacrolein, Crotonaldehyde, and Formaldehyde in Organic Synthesis

"Heptil" (unsymmetrical dimethylhydrazine-UDMH) is extensively employed worldwide as a propellant for rocket engines. However, UDMH constantly loses its properties as a result of its continuous and uncontrolled absorption of moisture, which cannot be rectified. This situation threatens its long-term usability. UDMH is an exceedingly toxic compound (Hazard Class 1), which complicates its transportation and disposal. Incineration is currently the only method used for its disposal, but this process generates oxidation by-products that are even more toxic than the original UDMH. A more benign approach involves its immediate reaction with a formalin solution to form 1,1-dimethyl-2-methylene hydrazone (MDH), which is significantly less toxic by an order of magnitude. MDH can then be polymerized under acidic conditions, and the resulting product can be burned, yielding substantial amounts of nitrogen oxides. This review seeks to shift the focus of MDH from incineration towards its application in the synthesis of relatively non-toxic and readily available analogs of various pharmaceutical substances. We aim to bring the attention of the international chemical community to the distinctive properties of MDH, as well as other hydrazones (such as glyoxal, acrolein, crotonal, and meta-crolyl), wherein each structural fragment can initiate unique transformations that have potential applications in molecular design, pharmaceutical research, and medicinal chemistry.

Diethylzinc-promoted carboxylation of aryl/alkenyl boronic acids with CO2

The carboxylation of aryl and alkenyl boronic acids with CO2 is rarely studied and only achieved using copper salts as the catalyst in the presence of a strong base. Herein, we report a diethylzinc-promoted carboxylation of aryl or alkenyl boronic acids with carbon dioxide. The reaction does not require a transition-metal catalyst, and has simple and mild conditions and a broad substrate scope.

Dearomative 1,6-addition of P(O)–H to in situ formed p-QM-like ion pairs from 2-benzofuryl-ols to C3-phosphinoyl hydrobenzofurans

We report a dearomative C3-phosphorylation and a tandem C3-phosphorylation/aromatization of 2-benzofuryl-ols with P(O)–H species to afford C3-phosphinoyl hydrobenzofurans and benzofurans, respectively.

(Substituted)-benzo[b]thiophene-4-carboxamide Synthesis and Antiproliferative Activity Study

Background:

Thiophene ring forms important building block in medicinal chemistry. Literature reveals that thiophene ring in combination with different groups shows different activity. By keeping these things in mind we have designed and synthesized a new series of amide and sulfonamide coupled thiophene. A series of novel substituted 3-sulfamoylbenzo[b]thiophene-4- carboxamide molecules containing sulfonamide and amide group were designed, synthesized and used for anti-proliferative activity study.

Methods:

The final compounds 16-36 were synthesized by using series of reactions comprising sulfonation, sulfonamide coupling, hydrolysis and peptide coupling. The yields of compounds 16- 36 are in the range of 90-98%. The structures of the synthesized compounds were elucidated and confirmed by 1H NMR, 13C NMR, LCMS and the purity was checked through HPLC analysis. The compounds were further tested for their in vitro anticancer activity against a series of cell lines A549, HeLa, MCF-7 and Du-145.

Results:

The intermediates 8-13, 15 and final compounds 16-36 were synthesized in good yields. The synthesized compounds were further tested for their anticancer activity and most of compounds showed moderate to good anticancer activity against all four cell lines.

Conclusion:

We have synthesized 21 compounds and were screened for anticancer activity against MCF-7, HeLa, A-549 and Du-145 cancer cell lines. Most of the compounds were active for tested cell lines with IC50 value in the range of 1.81 to 9.73 μM. The compounds 18, 19, 21, 25, 30, 31 and 33 are most active in cell line data with IC50 value in the range of 1.81 to 2.52 μM.

Synthesis and Evaluation of Pyridyloxypyridyl Indole Carboxamides as Potential PET Imaging Agents for 5-HT2C Receptors

Nine pyridyloxypyridyl indole carboxamides were synthesized and displayed high affinities for 5-HT_2C receptors and high selectivity over 5-HT_2A and 5-HT_2B. Among them, 6-methyl-N-[6-[(2-methyl-3-pyridinyl)oxy]-3-pyridinyl]1H-indole-3-carboxamide (8) exhibits the highest 5-HT_2C binding affinity (K_i = 1.3 nM) and high selectivity over 5-HT_2A (∼1000 times) and 5-HT_2B (∼140 times). [¹¹C]8 was synthesized by palladium-catalyzed coupling reaction between pinacolboranate 16 and [¹¹C]CH₃I with an average radiochemical yield of 27 ± 4% (n = 8, decay-corrected from end of [¹¹C]CH₃I synthesis). MicroPET imaging studies in rhesus monkeys showed regional uptake of [¹¹C]8 in the choroid plexus, whereas the bindings in all other brain regions were low. The specific binding in the choroid plexus was confirmed by administration of a blocking dose of 0.1 mg/kg of the 5-HT_2C antagonist SB-242084.

Copper-mediated trifluoroacetylation of indoles with ethyl trifluoropyruvate

Direct trifluoroacetylation of indoles with ethyl trifluoropyruvate as a trifluoroacetylating reagent has been developed.

A new biarylphosphine ligand for the Pd-catalyzed synthesis of diaryl ethers under mild conditions

A new bulky biarylphosphine ligand (L8) has been developed that allows the Pd-catalyzed C-O cross-coupling of a wide range of aryl halides and phenols under milder conditions than previously possible. A direct correlation between the size of the ligand substituents in the 2', 4', and 6' positions of the nonphosphine containing ring and the reactivity of the derived catalyst system was observed. Specifically, the rate of coupling increased with the size of these substituents.

Insights into binding modes of 5-HT2c receptor antagonists with ligand-based and receptor-based methods

5-hydroxytryptamine-2c (5-HT2c) receptor antagonists have clinical utility in the management of nervous system. In this work, ligand-based and receptor-based methods were used to investigate the binding mode of h5-HT2c receptor antagonists. First, the pharmacophore modeling of the h5-HT2c receptor antagonists was carried out by CATALYST. Then, the h5-HT2c antagonists were docked to the h5-HT2c receptor model. Subsequently, the comprehensive analysis of the pharmacophore and docking results revealed the structure-activity relationship of 5-HT2c receptor antagonists and the key residues involved in the interactions. For example, three hydrophobic points in the ligands corresponded to the region surrounded by Val135, Val208, Phe214, Ala222, Phe327, Phe328 and Val354 of the h5-HT2c receptor. The carbonyl group of compound 1 formed a hydrogen bond with Asn331. The nitrogen atom in the piperidine of compound 1 corresponding to the positive ionizable position of the best pharmacophore formed the electrostatic interactions with the carbonyl of Asp134, Asn331 and Val354, and with the hydroxyl group of Ser334. In addition, a predictive CoMFA model was developed based on the 24 compounds that were used as the training set in the pharmacophore modeling. Our results were not only useful to explore the detailed mechanism of the interactions between the h5-HT2c receptor and antagonists, but also provided suggestions in the discovery of novel 5-HT2c receptor antagonists.

Carboxylation of C-H bonds using N-heterocyclic carbene gold(I) complexes

A highly efficient [(NHC)Au(I)]-based (NHC = N-heterocyclic carbene) catalytic system for the carboxylation of aromatic and heteroaromatic C-H bonds was developed. The significant base strength of the Au-OH species is at the origin of the activation process and permits the facile functionalization of C-H bonds without the use of other organometallic reagents.