Thomas M. Judge

A titanium (IV) mediated one-pot double condensation synthesis of 5,6-dihydro-4H-pyran-4-ones

Abstract An alternative method for the synthesis of 2-amino-5,6-dihydro-4H-pyran-4-ones and 5,6-dihydro-4H-pyran-4-ones is described. This preparation makes use of the condensation of titanium enolates derived from β-hydroxy ketones with phosgene iminium chloride or trimethylorthoformate, respectively. The in situ formation of the necessary titanium complex from an aldol condensation using simple ketone and aldehyde precursors makes for a one-pot double condensation synthesis of the desired dihydropyrones.

A novel asymmetric synthesis of atropisomeric 6-aryl pyrazinones via an unusual chirality transfer process. New chiral ligands for the GABAA/Chloride ionophore complex

Abstract Cyclization of ( S , S )- α -[(1-phenylethyl)amino]- α -(2-iodophenyl)acetonitrile 3a with (COCl) 2 in toluene or chlorobenzene afforeded the atropisomeric pyrazinone ( aS , S ) 6-(2-α-iodophenyl)-3,5-dichloro-1-(1-phenylethyl)-2(1H)-pyrazinone 7a in 57% yield. With smaller ortho substituents, mixtures of atropisomers were obtained. Stereochemical assignments were made via X-Ray and NOE experiments.