A new class of sugar analogues for use in the investigation of sugar transport.

D-Mannose derivatives have been synthesised which are crosslinked through their C-4 hydroxyls to propyl-2-amine. Coupling to the amino group gave a fluorodinitrobenzene derivative, a nitroazidophenyl derivative and an azidosalicylamide derivative. Each of these derivatives was shown to have high affinity for the human erythrocyte sugar transport system. The affinity constant for the nitroazidophenyl derivative was not altered by temperature changes. In rat adipocytes treated with insulin, the affinity constants for the derivatives were up to 1000-fold lower than for the parent sugar. In the absence of insulin the affinity constants for the derivatives, but not for D-mannose, were 3-times higher than in insulin-treated cells. By preparation of radiolabelled derivatives we have shown that the compounds are not transported either by erythrocytes or by adipocytes. Thus the crosslinked sugars are good outside-specific analogues.