Page 35 - PG 504-theoretical notes-phyto-1-2024-2025..

Clinical pharmacy PharmD program Third level Phytochemistry-1 (PG-504)

Compound or No. of Number of Number of
group asym. isomers Enantiomer
Carbon pair

atom

1
1
1 2 = 2 2 /2 = 1
Glyceraldehyde
2
2
Aldotetrose 2 2 = 4 2 /2 = 2
3
3
Aldopentose 3 2 = 8 2 /2 = 4
4
4
Aldohexose 4 2 = 16 2 /2 = 8
n
Where: Number of isomers = 2 , n = Number of asymmetric carbon atoms
2
Number of enantiomer pairs = n / 2 (D and L).

➢ If the hydroxyl group of the chiral carbon farthest from the carbonyl group:
is pointing to the right, the sugar is designated as D (Dextro: Latin for on the

right side). If the hydroxyl group is pointing to the left, the sugar is designated
as L (Levo: Latin for on the left side).

1 CHO
2 1 CHO
H OH
3 H 2 OH
HO H
4 HO 3 H
H OH
highest numbered 5 HO 4 H highest numbered
"chiral" carbon H OH "chiral" carbon
6 CH OH 5 CH OH
2
2
D-Glucose L-Arabinose

CHO
HO H CHO
H OH HO H
HO H H OH
highest numbered highest numbered
"chiral" carbon HO H H OH "chiral" carbon
CH OH CH OH
2
2
L- glucose D-Arabinose

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