Wn. mr spectra were determined on ti Vairian A-60 spectrometer in DMSO-d, with TMS as internal reference. 1. r. spectra were determined with a Unicam-SP NOG, using the KBr R. afer technique. All melting points were taken on a Thomas-Hoover aparatm and are uncorrected. The usual procedure consisted of diluting with water, extracting with methylene chloride, drying over MgSO,, removing the solvent under reduced pressure and ...