Page 7 - Phytochemistry 2 (06-PG 605)

Solubility:

As a general rule:

 The free alkaloid bases are
 soluble in organic solvents.
 sparingly soluble in H2O

 Alkaloid salts are
 soluble in H2O
 sparingly soluble in organic solvents.

 Alcohol, dissolve both (bases & salts).

Exceptions:

a) H2O-soluble alk. bases

• Caffeine, and still
• Colchicines Soluble in organic solvents
• Ephedrine
• Pilocarpine

• Quaternary alk and Insoluble in organic solvents
• Alk. N-oxides because they are ionic comp.

b) Alk. bases very sparingly soluble in org. solvent
e.g. Morphine insoluble in CHCL3 & Ether moderately Soluble in alc. (1:300)

C) Alkaloidal salts sol in organic solvents

Lobeline HCl Soluble in CHCl3

d) Alk. salts sparingly soluble in H2O
Quinine sulphate (1:810)

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