May-June 1983 Notes 735 EXPERIMENTAL All melting points were taken on a capillary melting point apparatus and are uncorrected. The nmr spectra were taken on a Varian A-60 spectrophotometer, in deuteriochloroform solution, using TMS as the in- ternal standard. The ir spectra were determined using a Perkin Elmer 257 spectrophotometer. Mass measurements were carried out on a Varian CHI mass spectrometer. The equilibrium constant and ...