A 4-Hydroxy-L-proline glycoside of 2-amino-2-deoxy-D-glucose* NOTES Previous papers from this laboratory described the synthesis and stability of W2,4_dinitrophenylserine' and N-2,4-dinitrophenylthreonine' glycosides of 2-amino-2-deoxy-D-glucose. The present paper extends this series to 4-hydroxy-L-proline3-6. Glycosides of hydroxyproline are postulated as connective linkages in tibrilproteins',' and in the junction of glycoproteins to polysaecharide ground-substanceg-12. A Koenig&Knot-r condensation2J3J4 was used to couple 2-acetamido-3,4,6tri-0-acetyl-2-deoxy-a-D-glucopyranosyl chloride15 to the syrupy jV-2,Cdinitrophenyl-4-hydroxy-L-proline methyl ester (2). A crystalline glycoside (4) was isolated by preparative thin-layer chromatography (t.1.c.). The structure of the glycoside was confirmed by elementary analysis, optical rotation, i.r. and n.m.r. spectra, and by acid hydrolysis and identification of the products by t.1.c. The H-l signal of the hexosamine moiety (r 5.20) showed a splitting (J1,2 9 Hz) indicative of the B-D anomeric con-figuration16-'8. An orthoacetate structure for the glycoside1gg20 was considered improbable because no signal at ca. 5 8.3-8.5 (orthoacetate methyl g.roup21) was observed. The acid stability of the glycoside, as well as steric considerations, also ruled out an orthoacetate structure. Pure fron.r-4-hydroxy-L-proline was the starting material for synthesis of the N-dinitrophenyl derivative (l), the N-dinitrophenyl methyl ester (2), and the 4-O-ptolylsulfonyl-IV-dinitrophenyl methyl ester (3). Substances l-3 gave n.m.r. spectra very similar to the hydroxyproline signals in the spectrum of the glycoside 4. Nevertheless, NOz rr 1 R=H, R'=H 0 2 R=H. R'=Me No, 3 R=Ts, R'=Me N 4 R =2-acetamido-3,4.6-9 CC@' vi-O-acetyl-2-deoxy-/3-D-glucopyranosyl R'=Me RO the geometric configuration of the pyrrolidine ring in 4 cannot be stated definitively, because the effects of esterikation or glycosidation on the ring configuration are not known. The structure of the glycoside is simply assigned as 6O-(2-acetamido-3,4,6tri-O-acetyl-2-deoxy-~-~-glucopyranosyl)-N-2,4-dinitrophenyl-~hydroxy-~-pro~ne methyl ester (4). Glycosides of N-2,4dinitrophenylserine' and N-2,4-dinitrophenyl-threonine',