CHEM1611 2014-J-8 June 2014 • the Open Chain Form of D-Mannose Has

Home , Fischer projection, Haworth projection

CHEM1611 2014-J-8 June 2014 Marks The open chain form of D-mannose has the structure shown. • 6

Draw the Haworth projection of β-D-mannopyranose.

Draw the major organic product of the reaction of D-mannose with the following reagents.

What is a reducing sugar?

A sugar that reduces Tollens’ or Fehling’s reagent. Sugars containing aldehyde or hemiacetal groups are reducing sugars.

ANSWER CONTINUES ON THE NEXT PAGE CHEM1611 2014-J-8 June 2014

Give the Haworth formula of a non-reducing disaccharide that yields D-mannose as the only product on acid hydrolysis.

CHEM1611 2013-J-9 June 2013 Marks Consider the following two monosaccharides, (A) and (B). • 6

β-D-altropyranose α-D-xylofuranose Draw Fischer projections of the open chain forms of (A) and (B). (A) (B)

Draw the major organic product of the reaction of D-altropyranose with the following reagents.

Draw the Haworth stereoformula of a non-reducing disaccharide formed from (A) and (B).

CHEM1611 2012-J-9 June 2012 Marks The open chain form of D-talose is in equilibrium with two pyranose forms (L) and • 7 (M). Draw Haworth projections of (L) and (M).

(L) (M)

D-talose

Give the Haworth stereoformula of one of the products obtained when D-talose is treated with excess methanol in the presence of an acid catalyst.

Concentrated HNO3 oxidises aldehydes and primary alcohols to carboxylic acids, but does not oxidise secondary alcohols. Treatment of either D-talose or the aldohexose D-altrose with concentrated HNO3 gives the diacid (N). Give the Fischer projection of D-altrose.

(N)

Draw the Haworth stereoformula of a non-reducing disaccharide formed from D-talose.

CHEM1611 2010-J-10 June 2010 Marks • Consider the following two monosaccharides, ( L) and ( M). 8

CH2OH CH2OH O O H OCH H OH H 3 H OH H OH H HO H (L) HO H (M) H H OH OH methyl β-D-glucopyranoside β-D-glucopyranose

Describe a chemical test that could be used to distinguish ( L) from ( M). Include in your answer, the reagent you would use, what would be observed and a chemical equation that explains what is occurring in the reaction.

+ – Tollens reagent, [Ag(NH 3)2] /OH .

This will give no reaction with (L), but will oxidise (M). In the process, the + [Ag(NH 3)2] ion is reduced to metallic Ag which deposits as a silver mirror.

Give the reagents to convert ( L) to a H+/H O/heat mixture of ( M) and the α-anomer of ( M). 2

+ Give the reagents to convert ( M) to ( L). excess CH 3OH / H catalyst

Give the structure of the isomer of ( L) also produced in the preceding reaction.

Sugar ( M) exists in equilibrium with an open chain form. Give the Fischer projection of this open chain form.

List the functional groups present in ( L). primary and secondary alcohol, acetal

CHEM1611 2010-J-10 June 2010

CHEM1611 2010-J-11 June 2010

• Marks Tuftsin is a tetrapeptide (Thr-Lys-Pro-Arg) produced by enzymatic cleavage of the 6 Fc-domain of the heavy chain of immunoglobulin G. It is mainly produced in the spleen and its activity is related primarily to immune system function. O H H N N 2 N OH O O O NH tuftsin NH

NH2 HO HN NH2

Draw the Fischer projections of the four L-amino acids that result from the acid hydrolysis of tuftsin.

COOH

H2N H

CHEM1611 2009-J-10 June 2009 Marks • Shown below are the Haworth structure of β-D-mannopyranose and the Fischer 8 projection of D-galactose. CHO H OH HO H CH2OH O OH HO H OH HO H OH

HO CH2OH β-D-mannopyranose D-galactose

Draw structures for the following sugars. Fischer projection of D-mannose Haworth structure of α-D-galactopyranose

CHO HO H CH2OH HO O HO H OH H OH OH H OH HO CH2OH

Give the product(s) obtained when D-mannose is treated with acidified methanol.

CH OH 2 CH2OH O OCH3 O OH HO + OH HO

HO HO OCH3

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CHEM1611 2009-J-10 June 2009

Draw the structure of any non-reducing disaccharide formed from D-mannose and D-galactose, indicating the configurations at the anomeric carbon atoms.

Any one of the following 4 structures .

CH2OH CH OH HO O 2 α HO O OH OH α

HO HO O CH2OH CH2OH O O OH HO α OH HO β HO HO O

CH OH CH OH O 2 2 O HO O OH HO α OH β HO

HO O CH2OH HO CH2OH O O OH β OH HO β

HO HO

How many different non-reducing disaccharides can be formed from D-mannose and D-galactose? What is the relationship between any two of these compounds?

4 diastereomers

CHEM1611 2008-J-5 June 2008

• Marks Complete the following table. 4 CONSTITUTIONAL REAGENTS/ STARTING MATERIAL FORMULA(S) OF MAJOR CONDITIONS ORGANIC PRODUCT(S)

O OH O OCH2CH3 CH CH 3CH 2OH / 3 OH CH3 OH catalytic H + OH OH OH OH

CO2 O OH HO H CH 3 OH H OH [Ag(NH3)2] / OH OH H OH OH HO H

CH3

CHEM1611 2007-J-12 June 2007 Marks • Consider the following two disaccharides A and B. 6

CH2OH CH2OH O H H O H H H H OH OH OH OH HO OH H H O O H H

H O H O

H H H H

HOH C HOH2C CH OH 2 CH2OH 2 OH OH OH OH

A B Classify each disaccharide as “reducing” or “not reducing”.

A: not reducing (no hemiacetal) B: reducing (hemiacetal present)

Both these disaccharides hydrolyse to give tagatose and mannose. Mannose is an aldohexose. Draw the Fischer projections of the open chain forms of mannose and tagatose. Fischer projection of mannose Fischer projection of tagatose

CHO CH2OH HO H O HO H H OH H OH H OH H OH HO H

CH2OH CH2OH

Mannose is classified as an aldohexose. What classification is given to tagatose?

ketohexose

Specify the above mannose as D-mannose or L-mannose. D-mannose

Specify the above tagatose as D-tagatose or L-tagatose. L-tagatose

CHEM1611 2006-J-10 June 2006

Marks • Consider the following two monosaccharides A and B. 7

CH2OH CH2OH OH HO O H O H OH H H H H OH H H H OH OH OH

A: α-D-galactopyranose B: β-D-ribofuranose

Give the Fischer projections of the open chain form of A and B. Fischer projection of D-galactose Fischer projection of D-ribose

CHO CHO

H OH H OH

HO H H OH

H OH CH2OH

CH2OH

Give the products obtained when D-ribose is treated with the following reagents.

Acidified methanol NaBH 4 in methanol solvent

CH2OH CH OH CH OH 2 H 2 OCH O O 3 H OH

H H and H H H OH H OCH H H 3 H OH

OH OH OH OH CH2OH

CHEM1611 2006-J-10 June 2006

Draw the Haworth structure of a non-reducing disaccharide, which yields D-galactose and D-ribose on acid hydrolysis.

CH2OH

OH O H H OH H

H OH O

CH2OH O

H H H H

OH OH

CHEM1611 2005-J-10 June 2005

Marks  An important group of oligosaccharides is the blood group antigens. The blood group 6 antigen of humans with blood group B can be represented by the partial structure below, in which R is a glycoprotein.

CH2OH R HO O O H CH OH 2 O H HO O H H H H O OH H H H O H OH H OH H H H H H3C

OH OH 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 pyranose antigen as a furanose or a pyranose.

Specify fucose as a hexose, a pentose or a tetrose. hexose

Give the Fischer projections of the open chain form of galactose and fucose. Fischer projection of galactose Fischer projection of fucose

CHO CHO

H OH HO H

HO H H OH

H * OH HO H

CH2OH CH3

On 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

CHEM1611 2004-J-9 June 2004 Marks  The stucture of D-mannose is shown below. Draw the Fischer projection of 10 L-mannose in the space provided.

CHO L-mannose

HO H CHO HO H H OH H OH H OH D-mannose H OH CH OH 2 HO H HO H

CH2OH

D-Mannose is in equilibrium with two cyclic pyranose forms. Give the Haworth projection of these two cyclic forms.

CH2OH CH2OH O O OH OH OH OH OH

OH OH OH

-anomer -anomer

Give the products obtained when D-mannose is treated with the following reagents.   methanol / H [Ag(NH3)2] /OH solution 1. NaBH4 2. dilute acid

CH2OH CH2OH CO2 O HO H HO H OH OH HO H HO H OH OCH3 H OH CH2OH H OH O OCH3 H OH H OH OH OH CH2OH CH2OH OH

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CHEM1611 2004-J-9 June 2004

Draw the Haworth structure of a reducing disaccharide, which, on acid hydrolysis, yields D-mannose as the only product.

CH2OH CH2OH O O OH OH OH OH OH

OH O

CHEM1612 2003-N-8 November 2003 Marks  The stucture of D-glucose is shown below. Draw the Fischer projection of L-glucose 9 in the space provided.

CHO L-glucose

H OH CHO HO H HO H H OH H OH D-glucose H OH CH OH HO H 2 HO H

CH2OH

D-glucose is in equilibrium with two cyclic pyranose forms. Give the Haworth projection of these two cyclic forms.

CH2OH CH2OH O OH O OH OH

OH OH OH

OH OH

Give the products obtained when D-glucose is treated with the following reagents. + + – methanol / H [Ag(NH3)2] / OH solution 1. NaBH4 2. dilute acid

CH2OH CO2 H OH H OH HO H HO H H OH H OH H OH H OH

CH2OH CH2OH

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CHEM1612 2003-N-8 November 2003

Draw the Haworth structure of a non-reducing disaccharide, which, on acid hydrolysis, yields D-glucose as the only product.

CH2OH

O OH

OH O

CH2OH

O OH

OH OH