Alkaloids (Pcog Lab)

What are alkaloids?

Nitrogen-containing organics

Common element in alkaloids

Nitrogen

Structure often in alkaloids

Heterocyclic ring

Do most alkaloids contain oxygen?

Yes

Main source of alkaloids

Plants

Reason called alkali-like

Basic nature

Alkaloids form salts with

Acids

Alkaloids biological activities

Anticancer, antibacterial, antiviral, CNS depressant

Physical state of most alkaloids

Crystalline substances

Alkaloids in plants occur as

Free state, salt, N-oxide

True alkaloids origin

Amino acids

True alkaloid nitrogen location

Heterocyclic ring

Example of true alkaloid

Atropine

Protoalkaloids origin

Amino acids

Protoalkaloids nitrogen location

Not in heterocyclic ring

Example of protoalkaloid

Ephedrine

Pseudoalkaloids origin

Not amino acids

Pseudoalkaloids nitrogen location

Heterocyclic ring

Example of pseudoalkaloid

Caffeine

False alkaloids reaction

False-positive with reagents

Example of false alkaloid

Capsaicin

Extraction based on alkaloid's

Basic nature

Extraction uses

Acid salts, alkalinization, solubility

First step of extraction

Preparation of sample

Liberation of free alkaloid base uses

Alkali treatment

Examples of alkali for liberation

Sodium carbonate, ammonia

Organic solvents for extraction

Ether, chloroform, benzene, dichloromethane

Post-extraction process

Purification

Crude alkaloid separation methods

Partitioning, chromatography, crystallization

Stas-Otto digestion solvents

Alcohol, tartaric acid

Stas-Otto removes impurities by

Water dilution

Stas-Otto extraction solvent

Ether or chloroform

Kippenberger’s digestion solution

Tannin in glycerol

Kippenberger’s digestion solution contains how much Tannin?

100g

Kippenberger’s digestion solution contains how much glycerol?

500g

Kippenberger’s digestion time

48 hours

Kippenberger’s digestion temperature

40°C

Kippenberger’s post-digestion heating

50°C

Purpose of Kippenberger heating

Coagulate proteins

Final step of Kippenberger’s process

Filtration

What is the taste of alkaloid sample?

Bitter

Color of alkaloid powder

White

Appearance of alkaloid sample

Glistening needles

Physical state of alkaloid

Solid

Melting point of alkaloid

236.2°C

Alkaloid water solubility at 25°C

46 mL

Alkaloid water solubility at 80°C

5.5 mL

Alkaloid water solubility at 100°C

1.5 mL

Alkaloid alcohol solubility at 25°C

66 mL

Alkaloid alcohol solubility at 60°C

22 mL

Alkaloid ether solubility at 25°C

530 mL

Alkaloid chloroform solubility at 25°C

5.5 mL

Alkaloid water solubility % at 25°C

2.2%

Alkaloid water solubility % at 100°C

66.7%

Alkaloid alcohol solubility % at 25°C

1.2%

Alkaloid alcohol solubility % at 60°C

4.5%

Alkaloid ether solubility % at 25°C

0.3%

Alkaloid ethyl acetate solubility %

2.5%

Alkaloid chloroform solubility %

18%

Alkaloid acetone solubility %

2%

Alkaloid benzene solubility %

1%

Alkaloid high solubility solvents

Chloroform, boiling water

Wagner’s reagent for alkaloids

Iodine, Potassium iodide

Wagner’s test positive for alkaloids

Reddish brown precipitate

Mayer’s reagent for alkaloids

Potassium Mercuric Iodide TS

Mayer’s test positive for alkaloids

Cream-colored precipitate

Valser’s reagent for alkaloids

Mercuric Iodide TS

Valser’s test positive for alkaloids

White precipitate

Hager’s reagent for alkaloids

Picric acid

Hager’s test positive for alkaloids

Yellow crystalline precipitate

Murexide test initial acid for alkaloids

Hydrochloric acid

Murexide test oxidizer for alkaloids

Potassium chlorate

Murexide test drying method for alkaloids

Steam bath

Murexide test ammonia source for alkaloids

Ammonia vapor

Murexide test positive result for alkaloids

Purple residue

Sonnenschein’s reagent for alkaloids

Phosphomolybdic acid

Sonnenschein’s test positive for alkaloids

Yellowish precipitate

Markey’s reagent for alkaloids

Formic aldehyde, concentrated sulfuric acid

Markey’s test positive for alkaloids

Bloodish-red

Vitali-Morin’s reagents for alkaloids

Nitric acid, KOH, acetone

Vitali-Morin’s test positive for alkaloids

Violet

Vasitsky’s reagent for alkaloids

Dimethylaminobenzaldehyde, sulfuric acid

Vasitsky’s test positive for alkaloids

Violet

Frede’s reagent for alkaloids

Sodium molybdate, sulfuric acid

Frede’s test positive for alkaloids

Red, blue, green

Erdmann’s reagent for alkaloids

Sulfuric, nitric acid

Erdmann’s test positive for alkaloids

Red

Mandelin’s reagent for alkaloids

Vanadate ammonia, sulfuric acid

Mandelin’s test positive for alkaloids

Violet

Van Urck’s reagent for alkaloids

Dimethylaminobenzaldehyde, ferric chloride, sulfuric acid

Van Urck’s test positive for alkaloids

Bluish-violet