Synthesis and characterization of picket porphyrin receptors that bind phosphatidylglycerol, an anionic phospholipid found in bacterial membranes.

The lipid binding ability of four urea-picket porphyrins designed to bind to both the phosphate anion portion as well as the glycerol hydroxyl groups of phosphatidylglycerol (PG) has been investigated. Isothermal titration calorimetry (ITC) and (1)H NMR were used to determine the receptor's stoichiometry of binding, association constants, and both the enthalpy and entropy of binding with the PG anion. Spectral evidence shows that the phosphate anion portion of PG is hydrogen bonded to the urea groups of the receptors.

A convenient, one-step synthesis of benzyl (Ar) ureas of the type ArCH(2)NHCONHR from Ar and R(1)OCH(2)NHCONHR via ureidoalkylation.

A method for the one-step C-ureidoalkylation of phenol, anisole, or aniline rings furnishing ArCH(2)NHCONHR (Ar = benzyl) products in moderate to good yields is described. With phenol ring systems, higher yields were attained when the reaction was worked up with an acidic ethanethiol addition to cleave any O-ureidoalkylation products that formed during the reaction.