Microwave-mediated synthesis of N-methyliminodiacetic acid (MIDA) boronates

Linker-Assisted CdS-TiO2 Nanohybrids as Reusable Visible Light Photocatalysts for the Oxidative Hydroxylation of Arylboronic Acids

A variety of phenols have been obtained in aqueous media with moderate to excellent chemical yields (≤100%) by using arylboronic acids and esters as substrates, a robust CdS-TiO₂ nanohybrid as a heterogeneous photocatalyst, visible light irradiation (467 nm), and an O₂-saturated atmosphere. The nanohybrid was prepared through a linker-assisted methodology that uses mercapto alkanoic acids as the organic linkers. The nanohybrid showed improved photocatalytic activity in the hydroxylation of substituted arylboronic acids and phenyl boronic esters compared with that of pristine CdS quantum dots. The nanohybrid can be reused in up to five photocatalytic cycles with ∼90% of its outstanding activity preserved.

A Convenient, Rapid, Conventional Heating Route to MIDA Boronates

A cheap, conventional, sealed heating reactor proved to be a useful alternative to a microwave reactor in the synthesis of a >20-member MIDA boronate library (MIDA = N-methyliminodiacetic acid). Reaction times were 10 min and work-ups were minimal, saving on energy and solvent usage.

Scale-up and optimization of the synthesis of dual CBP/BRD4 inhibitor ISOX-DUAL

ISOX-DUAL is a dual inhibitor of CBP/p300 (IC₅₀ = 0.65 μM) and BRD4 (IC₅₀ = 1.5 μM) bromodomains, and a useful chemical probe for epigenetic research. Aspects of the published synthetic route to this compound and its analogues are small-scale, poor-yielding or simply unamenable to scale-up without optimization. Herein we describe the development of a refined synthesis that circumvents the challenges of the original report, with notable improvements to several of the key synthetic transformations. Moreover, a general Suzuki Miyaura protocol for the late stage installation of alternative dimethyl-isoxazole acetyl-lysine (KAc) binding motifs is presented.

Pd-Catalyzed coupling of benzyl bromides with BMIDA-substituted N-tosylhydrazones: synthesis of trans-alkenyl MIDA boronates

A palladium-catalyzed stereoselective synthesis of alkenyl boronates from N-methyliminodiacetyl boronate (BMIDA)-substituted N-tosylhydrazone and benzyl bromides is developed. A range of trans-alkenyl MIDA boronates as single stereoisomers were obtained in moderate yields with good functional group compatibility. The resultant boronate products may be transformed to other boron-containing compounds and may also be directly used in cross-coupling reactions.

Ene reactions of 2-borylated α-methylstyrenes: a practical route to 4-methylenechromanes and derivatives

4-Methylenechromanes were prepared via a three-step process from 2-borylated α-methylstyrenes. This sequence is based on a key glyoxylate-ene reaction catalyzed by scandium(iii) triflate. The resulting γ-hydroxy boronates, which cyclise to seven-membered homologues of benzoxaborole on silica gel, were cleanly oxidized with sodium perborate, and then cyclised under Mitsunobu conditions. Additionally, several further functional transformations of 4-methylenechromanes or their precursors were carried out to illustrate the synthetic potential of these intermediates.

Elaboration of tetra-orthogonally-substituted aromatic scaffolds towards novel EGFR-kinase inhibitors

Nitration of three regioisomers of bromo-fluorobenzaldehyde proceeds regioselectively, notably with H2SO4/HNO3 at 0 °C. The thereby synthesized tetrasubstituted aromatics, endowed with orthogonal substituents, can be elaborated via Pd-catalysed coupling, reduction and reductive amination reactions. As a test-case, these compounds were converted into EGFR inhibitors related to Gefitinib, whose activity was rationalised by docking studies.

Isoskeletal Schiff base polynuclear coordination clusters: synthetic and theoretical aspects

This work addresses and enlightens synthetic aspects derived from our effort to systematically construct isoskeletal tetranuclear coordination clusters (CCs) of the general formula [TR₂Ln₂(LX)₄(NO₃)₂(solv)₂] possessing a specific defected dicubane topology.

Regioselective routes to orthogonally-substituted aromatic MIDA boronates

A series of tetrasubstituted aromatics has been synthesized, many of which are based on elaborated N-methyliminodiacetic acid (MIDA)-boronates.

Linchpin dienes: key building-blocks in the synthesis of polyenic frameworks

This review focuses on the preparation of dienic linchpin reagents and on their use in the synthesis of polyenic frameworks.