PREPARATION OF 2-AMINO-1,6-ANHYDRO-2,3-DIDEOXY-β-D-arabino-HEXOPYRANOSE. 1H- AND 13C-N. M. R. SPECTRA OF DEOXY DERIVATIVES OF 2-AMINO-1,6-ANHYDRO-2-DEOXY-D-GLUCOSE AND 2-AMINO-1,6-ANHYDRO-2-DEOXY-D-MANNOSE