Synthesis of sugar-organometallic conjugales: ferrocenyl monosaccharide derivatives

Abstract

Suitably blocked carbohydrates containing free thio 4, amino 5, and hydroxyl 10, 19 nucleophilic functionalities have been treated with (a) ferrocenecarbonyl chlorides 2 and 3, (b) N,N-dimethylaminomethylferrocene methiodide 12, and (c) ferrocenyl tosylate 16 to form the ferrocenyl sugar derivatives 6, 7, 8, 9, 11, 13, 14, 15, and 20. Direct conjugation of a free, water-soluble sugar to ferrocene was achieved by the formation of a Schiff's base between glucosamine hydrochloride 25 and ferrocene carboxaldehyde 24. The synthesis of ferrocenyl sugars using bridging group technology is exemplified by the conjugation of the thio sugar 4 to ferrocene via the versatile coupling reagent cyanuric chloride 21 to form the s-triazine compound 23. These products have been studied by 1H nmr spectroscopy: chemical shifts, coupling constants, and proton spin–lattice relaxation measurements.