.beta.-D-Allopyranoside, 2-(dimethylamino)-3a,5,6,6a-tetrahydro-5-hydroxy-6-(hydroxymethyl)-4H-cyclopentoxazol-4-yl 2-(acetylamino)-2-deoxy-, 3aS-(3a.alpha.,4.alpha.,5.beta.,6.alpha.,6a.alpha.)-