Morwenna S. M. Pearson-Long

Simple and convenient access to α,α,α-trisubstituted amides by double addition of Grignard reagents to acyl cyanohydrins

The double addition of Grignard (alkyl, aryl, alkenyl, alkynyl) reagents to acyl cyanohydrins was performed under unusually smooth conditions with a concomitant O-N acyl transfer, providing a very simple and general access to α,α,α-trisubstituted amides.

Synthesis and biological evaluation of 3-cyano-4H-chromene derivatives bearing carbamate functionality

BACKGROUND 2-Aminochromene derivatives display important pharmacological properties, including mainly antibiotic and anticancer activities. OBJECTIVE The study aims to synthesize new chromene derivatives via a new approach using Grignard reagents, for the evaluation of their antibiotic and antifungal properties. METHOD A series of novel 3-cyano-4-aminochromene derivatives bearing alkyl substituents at the 4-position was prepared for biological evaluation. RESULTS These compounds were obtained by the addition of various Grignard reagents into Nethoxycarbonyl- 3-cyanoiminocoumarines in moderate to good yields (72-96%). The reaction is completely regioselective. The new chromene derivatives were screened for their in vitro antimicrobial activities against a panel of six bacterial and three fungal strains using agar dilution method. CONCLUSION The antibacterial activity of the chromene derivatives was more pronounced on Gram-positive bacteria than on Gram-negative bacteria with a significant activity observed against Staphylococcus aureus. An interesting antifungal activity against Fusarium sp. and Fusarium oxysporum was also noticed.

Chapter 7:Titanium-based Catalysts for Asymmetric Transformations

Titanium is employed in a wide range of important enantioselective reactions, including epoxidations, reductions, nucleophilic additions, and cycloadditions. This chapter summarises the most important catalytic systems employed in these reactions and the sustainable aspects developed thereof. In particular, efforts to reduce the amount of catalyst (or the ligand) or the use of supported heterogeneous and homogeneous catalysts are described.