Synthesis and resolution of the antibiotic phosphonomycin are described. The structure is (-)(IR, 2S)-1,2-epoxypropylphosphonic acid.

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Nicarbazin, a drug used to control the protozoal disease coccidiosis in poultry, is a complex of the highly insoluble drug 4,4'-dinitrocarbanilide with 2-hydroxy-4,6-dimethylpyrimidine. The structures of this and other 4,4'-dinitrocarbanilide complexes have not been determined, but an analogous 2:1 complex of 4,4'-dinitrodiphenylamine with 1,4-diacetylpiperazine has been prepared in which the only possible bonds are hydrogen bonds between the amide carbonyls and amino hydrogens. Scanning electron microscopy revealed that micron-size crystals of nicarbazin disintegrate in water to form much smaller dinitrocarbanilide crystals. Similar complex dissolution in the gut of poultry may account for the greater effectiveness of dinitrocarbanilide when administered as complexed rather than uncomplexed drug. Particle size problems associated with other highly insoluble drugs and pesticides may be resolved by the use of nicarbazin-like complexes.

Homocysteine thiolactone (2) derivatives in which the nitrogen is acylated with groups containing acidic functionalities have been synthesized. These include the succinyl (3), the carboxymethylglutaryl (4), the 3-phosphonopropionyl (7), and the 3-sulfopropionyl (8) derivatives. These thiolactones can be used to introduce a thiol functionality into proteins such as the outer membrane protein complex of Neisseria meningitidis (OMPC) allowing conjugation with electrophilic ligands. This chemistry is the same as with N-acetylhomocysteine thiolactone (1), but their pKa values are such that at pH 7 concomitant negative charge is introduced into the conjugate. Such negative charge should neutralize some excess positive charge introduced when arginine- and lysine-rich peptides are bonded as ligands. In the case of OMPC, introduction of such positive charge appears to effect irreversible precipitation. The system has been studied using the maleimidopropionyl and bromoacetyltriarginine (9 and 10) derivatives as models. In select instances anionic spacers reduce the degree of precipitation relative to N-acetyl-homocysteine thiolactone derivatives.