Solvent-free esterification of carboxylic acids and alcohols in the presence of silphos [PCl3-n(SiO2)n] as a heterogeneous phosphine reagent
An efficient solvent-free method for the preparation of esters from various aromatic and aliphatic acids with primary, secondary, and tertiary alcohols using a heterogeneous phosphine reagent, silphos [PCl3-n(SiO 2)n], in good yields is reported.
SYNTHESIS OF 20-IODOEICOSANOIK AND 20--IODOEICOSANOIK ACIDS
20-Iodoeicosanoic acid (X) was prepared in 9 steps, its carbon cain being constructed from thiophene and ethyl ester chlorides of dodecanedioic and butanedioic acids.Isotope exchange afforded 20--iodoeicosanoic acid required for scintigraphic studies of the myocardium.Desulfuration of the thiophene precursor VIII was accompanied by formation of side products XI-XIX arising by cleavage of the thiophene C-C bonds.Desulfuration of the model compounds XX and XXI has shown that the formation of these products is general.