title: Synthesis and asymmetric reducing performance of chitin/dihydronicotinamide conjugates having glycine or L-leucine spacer arms.
abstract: Chitin/dihydronicotinamide conjugates having glycine or L-leucine spacer arms have been prepared and evaluated as asymmetric reducing agents. N-Nicotinoylglycine and N-nicotinoyl-L-leucine were synthesized and coupled with the amino group of water-soluble 50%-deacetylated chitin. The remaining free amino groups were acetylated, and the nicotinamide groups were transformed into dihydronicotinamide moieties by quaternization followed by reduction. The resulting L-leucine-containing conjugate reduced ethyl benzoylformate efficiently with high chemical yield and asymmetric selectivity, whereas the glycine-containing conjugate gave only poor results. The recovered L-leucine-containing conjugate was reduced to regenerate the dihydronicotinamide structure and could be used again. The L-leucine residue has thus proved suitable as a spacer arm to achieve a high reducing performance.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Seikei University, Musashino-shi, Tokyo 180-8633, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kurita
authors.forename: Tabito
authors.initials: T
authors.lastname: Nishibori
authors.forename: Manabu
authors.initials: M
authors.lastname: Harata
mesh_terms: D002686:Chitin / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D005998:Glycine / Q000737:chemistry; D007930:Leucine / Q000737:chemistry; D009536:Niacinamide / Q000031:analogs & derivatives* / Q000737:chemistry*; D010084:Oxidation-Reduction
chemical_list: D003432:Cross-Linking Reagents; C015145:dihydronicotinamide; D002686:Chitin; D009536:Niacinamide; D007930:Leucine; D005998:Glycine