Thionation: Glc NAc ‐Thiazoline Triacetate {(3 a R ,5 R ,6 S ,7 R ,7 a R )‐5‐Acetoxymethyl‐6,7‐Diacetoxy‐2‐Methyl‐5,6,7,7 a ‐Tetrahydro‐3 a H ‐Pyrano[3,2‐ d ]Thiazole}