Experimental

disorder in main residue; R factor = 0.039; wR factor = 0.097; data-to-parameter ratio = 14.2. The title molecule, C7H15NO5, the major product from selective enzymatic oxidation followed by hydrogenolysis of the corresponding azidoheptitol, was found by X-ray crystal-lography to exisit in a chair conformation with three axial hydroxyl groups. One of the hydroxymethyl groups is disordered over two sets of sites in a 0.590 (3):0.410 (3) ratio. In the crystal, O—H O, O—H (O,O), O—H N and N—H O hydrogen bonding occurs