IR STUDY ON AQUEOUS-SOLUTION BEHAVIOR OF D-CYCLOSERINE

IR spectra were measured for an antitubercular agent, D-cycloserine (C S), and the hydrolyzate, beta-aminooxy-D-alanine (AOA) and the dimer, cis-3,6-bis (aminooxymethyl)-2, 5-piperadinedione (CS-dimer) at variou s pHs in aqueous solutions. Molecular species existing in the ionic eq uilibria were characterized by the pH dependence of the spectra. Band assignments were carried out by reference to the spectra of D2O soluti ons and those of related compounds. Spontaneous transformation of CS t o CS-dimer was observed by the IK spectra for the neutral aqueous solu tion. The spectral evidence suggested that the non-ionic form of CS pl ays a key role in the dimerization process.