2-Dahp 2-Dehydro-3-deoxy-D-arabino-heptonate 7-phosphate 2627-73-8 3-Deoxy-D-arabino-hept-2-ulosonate 7-phosphate 3-Deoxy-D-arabino-heptulosonic acid 7-phosphate 3-Deoxy-arabino-heptulonate 7-phosphate C04691 DAHP