CEM1612 2003--8 ovember 2003 The stucture of D-glucose is shown below. Draw the Fischer projection of L-glucose in the space provided. D-glucose C C 2 L-glucose C 9 C 2 D-glucose is in equilibrium with two cyclic pyranose forms. Give the aworth projection of these two cyclic forms. C 2 C 2 Give the products obtained when D-glucose is treated with the following reagents. methanol / + [Ag( 3 ) 2 ] + / solution 1. ab 4 2. dilute acid C 2 C 3 + C 2 C 3 C 2 C 2 C 2 C 2 ASWER CTIUES TE EXT PAGE
CEM1612 2003--8 ovember 2003 Draw the aworth structure of a non-reducing disaccharide, which, on acid hydrolysis, yields D-glucose as the only product. C 2 C 2
CEM1611 2004-J-9 June 2004 The stucture of D-mannose is shown below. Draw the Fischer projection of L-mannose in the space provided. D-mannose C C 2 L-mannose C 10 C 2 D-Mannose is in equilibrium with two cyclic pyranose forms. Give the aworth projection of these two cyclic forms. C 2 -anomer C 2 -anomer Give the products obtained when D-mannose is treated with the following reagents. methanol / [Ag( 3 ) 2 ] / solution 1. ab 4 2. dilute acid C 2 C 3 C 2 C 2 C 2 C 3 C 2 C 2 ASWER CTIUES TE EXT PAGE
CEM1611 2004-J-9 June 2004 Draw the aworth structure of a reducing disaccharide, which, on acid hydrolysis, yields D-mannose as the only product. C 2 C 2
CEM1611 2005-J-10 June 2005 An important group of oligosaccharides is the blood group antigens. The blood group antigen of humans with blood group B can be represented by the partial structure below, in which R is a glycoprotein. 6 C 2 C 2 R 3 C The type B blood group antigen can be hydrolysed to galactose (2 mole equiv.), fucose (1 mole equiv.) and a glycoprotein unit. Specify the fucose unit in the type B blood group antigen as a furanose or a pyranose. Specify fucose as a hexose, a pentose or a tetrose. pyranose hexose Give the Fischer projections of the open chain form of galactose and fucose. Fischer projection of galactose Fischer projection of fucose C C * C 2 C 3 n your Fischer projection of galactose indicate with an asterisk (*) the carbon atom used in the D/L convention. Specify the galactose from blood antigen as D-galactose or L-galactose. D-galactose Specify the fucose from blood antigen as D-fucose or L-fucose. L-fucose
CEM1611 2005-J-8 June 2005 Complete the following table. STARTIG MATERIAL REAGETS/ CDITIS CSTITUTIAL FRMULA(S) F MAJR RGAIC PRDUCT(S) 1 C 2 C 3 / catalyst C 2 C 3 C 2 C 3
CEM1611 2006-J-7 June 2006 A stick representation for the active enantiomer of methadone, an analgesic used as a maintenance drug in the treatment of heroin addiction, is shown below. 6 (b) (a) (c) Give the molecular formula of methadone. C 21 27 Methadone contains a stereogenic centre. List the substituents attached to this stereogenic centre in descending order of priority according to the sequence rules. ighest priority Lowest priority C 3 What is the stereochemistry at this stereocentre? Write (R) or (S). (R) (X) List the functional groups present in methadone. tertiary amine, ketone, arene (aromatic ring) Treatment of methadone with ab 4 gives compounds (X) and (Y). Draw the structures of (X) and (Y). (Y) What is the stereochemical relationship between compounds (X) and (Y)? They are diastereomers
CEM1611 2006-J-7 June 2006
CEM1611 2007-J-7 June 2007 The nucleic base guanine is drawn below as a keto tautomer. Draw two other tautomers of guanine. 2 2 Tautomers include: 2 2 2 2