RESUMEN

A two-step, one-pot synthesis of 3-substituted 1H-dibenzo[e,g]indazoles in good to high yields via a LiOtBu-promoted intramolecular 1,3-dipolar cyclization of 2'-alkynyl-biaryl-2-aldehyde N-tosylhydrazones was developed. The N-Ts-hydrazones used were prepared in situ via the reactions of 2'-alkynyl-biaryl-2-aldehydes and TsNHNH2(p-methylbenzenesulfonohydrazide). Two types of signals related to the hydrogen bonds, forming in several products, were observed in the 1H NMR spectra recorded in DMSO-d6, assigned to N-H bonds in their dimeric species of product and tautomer.

RESUMEN

A catalyst-free coupling reaction between O-peracetylated, O-perbenzoylated, O-permethylated, and O-permethoxymethylated 2,6-anhydro-aldose tosylhydrazones (C-(ß-d-glycopyranosyl)formaldehyde tosylhydrazones) and aromatic boronic acids is reported. The base-promoted reaction is operationally simple and exhibits a broad substrate scope. The main products in most of the transformations were open-chain 1-C-aryl-hept-1-enitol type compounds while the expected ß-d-glycopyranosylmethyl arenes (benzyl C-glycosides) were formed in subordinate yields only. A mechanistic rationale is provided to explain how a complex substrate may change the well-established course of the reaction.

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RESUMEN

The synthesis and biological activity evaluation of benzenesulfonyl hydrazones is quite frequently encountered in scientific literature. This class of compounds is very interesting due to the wide spectrum of potential applications in the field of medicinal chemistry. The benzenesulfonyl hydrazones possess mainly antibacterial, antifungal, anticancer, antidepressant properties, activity against Alzheimer's disease, insecticidal activity and ability to inhibit the activity of enzymes. This review is an attempt to gather the literature findings on the most promising bioactive benzenesulfonyl hydrazones.

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RESUMEN

Metal-free photochemical carbene-transfer reactions of tosylhydrazones were developed under blue light irradiation at room temperature. This reaction constructs C-X (X=C, N, O, S) bonds and cyclopropanes from readily available and stable starting materials.

RESUMEN

Some N-tosylhydrazone derivatives were effectively synthesized under solvent-free conditions by using a grinding method at room temperature. The short reaction time, clean and mild process with simple workup and easy purification of the target compounds were salient features of the present protocol, which enables straightforward access to N-tosylhydrazones. Among the tosylhydrazone derivatives evaluated, compound 3 l exhibits excellent apoptosis-promoting and anticancer potential against triple-negative breast cancer (TNBC) cell lines. This research shows that our synthesized compound 3 l may be a desirable and effective therapeutic drug against TNBC.

RESUMEN

Polycyclic molecules featuring all-carbon quaternary bridgehead centers were synthesized through domino cyclizations between N-tosylhydrazones and boronic acids. Variations of the general cascade have been applied for the preparation of 3-quinuclidinones and related alkaloid-like scaffolds through transannular heterocyclizations. Moreover, the employment of 3-cyanopropyl and 4-cyanobutylboronic acids and α,ß-unsaturated N-tosylhydrazones led to spirocycles through unprecedented formal [n+1] cyclizations, including the stereoselective spirocyclization of the Hajos-Parrish ketone. The common feature of all the new reactions described is the creation of an all-carbon quaternary center by formation of two Csp3 -C bonds on the hydrazonic carbon atom. DFT-based calculations suggested the occurrence of cascade processes, which involve a diazo compound carboborylation followed by a 1,3-borotropic rearrangement on an intermediate allylboronic acid and a novel bora-aza-ene cyclization.

RESUMEN

Palladium-catalyzed cross-couplings of O-peracylated and O-permethylated 2,6-anhydro-aldose tosylhydrazones with aryl halides were studied under thermic conditions in the presence of LiOtBu and phosphine ligands. The reactions gave the corresponding aryl substituted exo-glycals as mixtures of diastereomers in 11-75% yields. The transformations represent a new access to these types of glycomimetic compounds. The double bond of some aryl substituted exo-glycals was saturated to give good yields of benzylic C-glycosyl derivatives.

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RESUMEN

Palladium(0)-catalysed hydro-alkylation or -alkenylation of alkoxyallenes with N-tosylhydrazones gives direct access to conjugated and skipped 1-alkoxydienes with high efficiency and excellent functional-group compatibility. The reaction is proposed to involve the in situ-formed t-butanol as proton source in the key step of the allylpalladium(II) species generation. Moreover, lithium iodide or iodobenzene are employed as an unprecedented iodide (I- ) reservoir to sustain the catalytic cycle.

RESUMEN

A rhodium(II)- or copper(I)-catalyzed formal intramolecular carbene insertion into vinylic C(sp2 )-H bonds is reported herein. This method provides straightforward access to 1H-indenes with high efficiency and excellent functional-group compatibility. Mechanistically, the reaction is proposed to involve the following sequence: metal carbene formation, intramolecular nucleophilic addition of the double bond to the electron-deficient carbene carbon atom, dearomatization, and finally a 1,5-H shift.

RESUMEN

This work describes a new approach to obtain new ß-vinylporphyrin derivatives through palladium-catalyzed cross-coupling reaction of 2-bromo-5,10,15,20-tetraphenylporphyrinatozinc(II) with N-tosylhydrazones. This is the first report of the use of such synthetic methodology in porphyrin chemistry allowing the synthesis of new derivatives, containing ß-arylvinyl substituents.

RESUMEN

A CuI-catalyzed reductive coupling of ketone-derived N-tosylhydrazones with amides is presented. Under the optimized conditions, an array of N-tosylhydrazones derived from aryl-alkyl and diaryl ketones could couple effectively with a wide variety of (hetero)aryl as well as aliphatic amides to afford the N-alkylated amides in high yields. The method represents the very few examples for reliably accessing secondary and tertiary amides through a reductive N-alkylation protocol.

RESUMEN

The reactions between alkenylboronic acids and tosylhydrazones derived from substituted cyclohexanones lead to the construction of disubstituted cyclohexanes with total regio- and stereoselectivity. In these transition-metal-free processes, a Csp(3) -Csp(2) and Csp(3) -H bond are formed on the same carbon atom. The stereoselective reaction is general for 2-, 3-, and 4-substituted cyclohexanone tosylhydrazones, as well as for 2-substituted cyclopentanones. However, no stereoselectivity is observed for acyclic derivatives. DFT computational modeling suggests that the stereoselectivity of the reaction is determined by the approach of the boronic acid to the diazocyclohexane on its most stable chair conformation through an equatorial trajectory.

RESUMEN

A base-promoted three-component coupling of carbon dioxide, amines, and N-tosylhydrazones has been developed. The reaction is suggested to proceed via a carbocation intermediate and constitutes an efficient and versatile approach for the synthesis of a wide range of organic carbamates. The advantages of this method include the use of readily available substrates, excellent functional group tolerance, wide substrate scope, and a facile work-up procedure.

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RESUMEN

Potent anticancer 4-arylchromene agents 6, as restricted isoCA-4 analogues, were prepared with excellent yields by a rapid and versatile synthetic pathway. First, in the presence of PTSA in EtOH, a variety of arylalkynols 9 were transformed into substituted 4-chromanones 10 in a one pot procedure which include regioselective arylalkynols hydration, alcohol etherification, MOM-cleavage, and cyclization. Further palladium coupling reactions, using aryl halides and N-tosylhydrazones 11 gave access to a small library of functionalized 4-arylchromenes 6 with good yields. From this series of 4-arylchromenes, we have identified compound 6s which inhibit tubulin assembly at a micromolar level and demonstrate a remarkable nanomolar level of cytotoxicity against four human cancer cell lines. Docking studies showed that isoCA-4 and its restricted chromene analogue 6s adopt a similar positioning in the colchicine binding-site of tubulin.

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