Question

The molecular models of two sugars have been built for you. Sugar A is a mono ugar B is a disaccharide. In these models, the different colored balls represent the follow saccharide and groups of atoms: black - carbon, yellow - hydrogen, red -oxygen, and grem -cHoH. 1. Draw the Haworth and Fischer projections of sugar A in the boxes below Sugar Fischer Projection Fischer Projection Cyelic Model A Haworth Projection Open-chain Glucose a. Is sugar model A an aldohexose or a ketohexose? b. Does sugar model A contain a hemiacetal (Haworth Projection)? c. Does sugar model A belong to D-family or L-family? d. How many chirality/stereogenic centers are in sugar model A (refer to open-chain Fischer Projection)? Page | 59

Answer 1

Glucose HO HO O OH HOII" он OH H COH HC- OH HO он OH H20H Fischer Projection Fischer Projection Haworth Projection (Open Chain Form) (Closed Chain Form) (Closed Chain Form) (It provides more important (simple to find the up and down groups) to the stereochemical representation) a) it has a aldehyde group (-CO-H) hence, t s aldose due to the 6 carbon, it is referred as aldohexose b) Yes. addition of alcohol and aldehyd group leads to formation hemiacetal HO HO OR RO OR O OH Hemiacetal acetal OH

Glucose HO HO O OH HOII" он OH H COH HC- OH HO он OH H20H Fischer Projection Fischer Projection Haworth Projection (Open Chain Form) (Closed Chain Form) (Closed Chain Form) (It provides more important (simple to find the up and down groups) to the stereochemical representation) a) it has a aldehyde group (-CO-H) hence, t s aldose due to the 6 carbon, it is referred as aldohexose b) Yes. addition of alcohol and aldehyd group leads to formation hemiacetal HO HO OR RO OR O OH Hemiacetal acetal OH

d. Stereocenter is carbon that has four different groups но- он 3 HO он (2R,3R.4S,5S,6R)-6-(hydroxymethyl)tetrahydro-2H-pyran-2,3,4,5-tetraol