Stereocontrol in hydride addition to ketone-derived chiral N-acylhydrazones

Designing Potent Anti-Cancer Agents: Synthesis and Molecular Docking Studies of Thieno[2,3-d][1,2,4]triazolo[1,5-a]pyrimidine Derivatives

A new series of thieno[2,3-d][1,2,4]triazolo[1,5-a]pyrimidines was designed and synthesized using readily available starting materials, specifically, β-enaminoester. Their cytotoxicity was screened against three cancer cell lines, namely, MCF-7, HCT-116, and PC-3. 2-(4-bromophenyl)triazole 10b and 2-(anthracen-9-yl)triazole 10e afforded excellent potency against MCF-7 cell lines (IC50 = 19.4 ± 0.22 and 14.5 ± 0.30 μM, respectively) compared with doxorubicin (IC50 = 40.0 ± 3.9 μM). The latter derivatives 10b and 10e were further subjected to in silico ADME and docking simulation studies against EGFR and PI3K and could serve as ideal leads for additional modification in the field of anticancer research.

Ruthenium-Catalyzed Enantioselective Hydrogenation of Hydrazones

Prochiral hydrazones undergo efficient and highly selective hydrogenation in the presence of a chiral diphosphine ruthenium catalyst, yielding enantioenriched hydrazine products (up to 99% ee). The mild reaction conditions and broad functional group tolerance of this method allow access to versatile chiral hydrazine building blocks containing aryl bromide, heteroaryl, alkyl, cycloalkyl, and ester substituents. This method was also demonstrated on >150 g scale, providing a valuable hydrazine intermediate en route to an active pharmaceutical ingredient.

Lanthanide–EDTA complexes covalently bonded on Fe3O4@SiO2 magnetic nanoparticles promote the green, stereoselective synthesis of N-acylhydrazones

Highly efficient stereoselective synthesis of E–N-acylhydrazones using magnetic nanoparticles-Ln³⁺ as heterogeneous catalysts.

Control of asymmetry in the radical addition approach to chiral amine synthesis

The state-of-the-science in asymmetric free radical additions to imino compounds is presented, beginning with an overview of methods involving stereocontrol by various chiral auxiliary approaches. Chiral N-acylhydrazones are discussed with respect to their use as radical acceptors for Mn-mediated intermolecular additions, from design to scope surveys to applications to biologically active targets. A variety of aldehydes and ketones serve as viable precursors for the chiral hydrazones, and a variety of alkyl iodides may be employed as radical precursors, as discussed in a critical review of the functional group compatibility of the reaction. Applications to amino acid and alkaloid synthesis are presented to illustrate the synthetic potential of these versatile stereocontrolled carbon-carbon bond construction reactions. Asymmetric catalysis is discussed, from seminal work on the stereocontrol of radical addition to imino compounds by non-covalent interactions with stoichiometric amounts of catalysts, to more recent examples demonstrating catalyst turnover.

Intermolecular alkyl radical additions to enantiopure N-tert-butanesulfinyl aldimines

The sulfinyl group in (R)-N-tert-butanesulfinyl aldimines provides efficient control of the stereoselectivity in the intermolecular reactions with alkyl radicals. The methodology is applicable to aryl, heteroaryl, benzyl, and alkynyl imines, even those containing CN, CO2Me, COR, and OH groups. The best results are attained with hindered radicals (tertiary and secondary ones) without C═N bond reduction. This reaction complements the well-established organometallic additions to N-sulfinyl aldimines to obtain enantiomerically pure functionalized α-branched primary amines.

N-Acylhydrazones as Versatile Electrophiles for the Synthesis of Nitrogen-Containing Compounds

The use of N-acylhydrazones as electrophiles in reactions with nucleophiles has recently made some important advances. N-Acylhydrazones, which can be readily prepared and stored, act as stable imine surrogates in these reactions. The hydrazide products are useful, often chiral building blocks which can be transformed into various nitrogen-containing compounds by cleavage of the N--N bond. The N-acyl groups often play important roles as templates for metal catalysis in controlling stereochemistry. This Minireview summarizes the most recent results of N-acylhydrazone chemistry, and provides an overview of current developments in this field.