KETONES, ALDEHYDES AND CARBOXYLIC ACIDS

aldehydes and ketones

• are characterized by the carbonyl functional group (C=O)

• are responsible for many flavors and odors

vanillin

vanilla flavor (aldehyde)

cinnamaldehyde

cinnamon flavor (aldehyde)

(R)-Carvone

spearmint flavor (ketone)

benzaldehyde

almond flavor (aldehyde)

progesterone and testosterone

Many important biological compounds also exhibit the carbonyl group, including __________, the female and male sex hormones.

tollen’s reagent

• prepared by dissolving AgNO₃ in water, adding NaOH to precipitate silver ion as Ag₂O

• (+) result: silver-mirror

oxidative cleavage

• K₂Cr₂O₇ or KMnO₄ at high temperature

• Conc. HNO₃

• Keto → ENOL (-ene + -ol) → RCOOH

primary alcohol

reduction of aldehyde → __________

secondary alcohol

reduction of ketone → ________

H₂, Pt or Pd

catalyst used to during reduction of aldehydes and ketones at room temp (25°C),

Lithium Aluminum Hydride (LiAlH₄ or LAH)

Reduces aldehyde, ketones and carboxylic acids

Sodium borohydride (NaBH₄)

reduces aldehyde and ketones ONLY

carboxylic acids

• compounds with -COOH group

• higher boiling points

• more water soluble than alcohols

acetic acid

responsible for the pungent smell of vinegar

butanoic acid

responsible for the rancid odor of sour butter

hexanoic acid

responsible for the odor of dirty socks

lactic acid

responsible for the taste of sour milk

acetylsalicylic acid

aspirin, a widely used analgesic

4-aminosalicylic acid

used in the treatment of tuberculosis

isotretinoin

used in the treatment of acne

water-solubility of carboxylic acids

__________ decreases as chain length increases