1. Chem. Abstr., 62, 7761d (1965).
2. (Netherlands Appl., 6,400,946).
3. Melting points are uncorrected. The nmr spectra were determined on a Varian HA-100D spectrometer, the mass spectra on an AEI ms-9 instrument. Silica gel G covered micro slides obtained from Analtech Inc., Newark, Delaware were used for thin layer chromatography and spots were visualized with Cl2-tolidine (4a). The absolute methanol used was commercial grade-Magnesium sulfate was used for drying.