Some Interesting Occurrences of Aldehydes and Ketones in Natural Products

Organic Chemistry 212 Minh Anh Nguyenminhanhnguyen@q.com

• Some naturally occurring aldehydes and ketones are important in living systems. Some function as sex hormones; others are used as flavorings and tasting. For example, testosterone, the male sex hormone, and progesterone, a hormone secreted by the ovaries that stimulates the growth of cells in the uterine wall, both contain a ketone functional group. In addition, aldehydes and ketones can be found in foods, fragrance chemicals, and medicines. Some aldehydes are responsible for very pleasant tastes and odors, such as vanillin from vanilla beans, benzaldehyde from almonds, cinnamaldehyde from cinnamon, etc. Formaldehyde is used to preserve tissue. Acetaldehyde causes the unpleasant “hangover” feeling that can result from consuming alcoholic beverages. Ketones are also responsible for many well-known odors such as those of garlic and camphor. Muscone or musk oil is an ingredient in perfumes. The drug cortisone is a ketone used to relieve individuals with rheumatism. Other uses for ketones include industrial solvents such as acetone, which are also used in every-day things like nail polish remover. In the human body, the scent of acetone in saliva or urine can warn of uncontrolled diabetes

Structures of Aldehydes and Ketones• Both aldehydes and ketones contain a carbonyl

group. The carbonyl is a very polar group. • Aldehydes have at least one H attached. Ketones

have two R’s attached to the carbonyl group.Aldehydes

R H

O

Ketone

R R

O

sp2

Carbonyl group

pentanalO

O

2-pentanone

The differences between aldehydes and ketones • Aldehydes are less steric hindered than ketones. • Aldehydes have fewer electron donating groups (EDG's)

which can stabilize an electron-poor area• Aldehydes are readily oxidized to carboxylic acids, and

ketones resist oxidation. The oxidation of a primary alcohol produces an aldehyde, and the oxidation of a secondary alcohol yields a ketone.

Physical Properties of Aldehydes and Ketones

• Aldehydes and Ketones have higher boiling points than hydrocarbons, but have lower boiling points than alcohols, because they have no H attached to the O.

• Aldehydes and Ketones have strong odors, and are often used as flavorings or scents.

• Small aldehydes are reasonably soluble in water. Large aldehydes are less polar and dissolve more readily in nonpolar organic solvents.

Aldehydes can be found in food • Flavoring and or scent made from Aldehydes

Aldehydes can be found in food

Octanal is found both in orange oil and orange juice. It's used industrially to supply an orange, especially to perfumes and food preparations.

Aldehyde can be found in Human Body and Fragrance Chemical

Retinal (retinaldehyde) is one of the many forms of vitamin A and the chemical basis of Human and animal vision. It allows certain microorganisms to convert light into metabolic energy.

Aldehyde can be found in Fragrance Chemical

Aldehydes can be found in medicine• Formaldehyde is also an extremely toxic substance; it has an irritating odor.• Formaldehyde denatures proteins, rendering them insoluble in water and resistant to bacterial decay. It is used to preserve tissue.• Acetaldehyde is produced when one’s liver metabolizes ethanol (drinking alcohol) and causes the symptoms of a hangover.

Ketones can be found in human body• Testosterone is the male sex hormone. Progesterone is

the hormone produced by the female ovary after ovulation.

• Aldosterone is secreted when blood sodium ion levels are too low to cause the kidney to retain sodium ions. If sodium levels are elevated, aldosterone is not secreted, so that some sodium will be lost in the urine. Aldosterone also controls swelling in the tissues.

Ketones can be found in Insects • Pheromones are chemicals released by an organism into its environment

enabling it to communicate with other members of its own species. They are released by both insects and mammals in many situations such as finding food and mates, aggregating to take advantage of food resources, protecting sites of ovipositor, and escaping predation, etc.

structure of the western pine beetle pheromone

Ketones can be found in one’s health• In human bodies, Ketones are transported from the liver to other

tissues. • Ketones are chemicals which appear in the blood and urine when body fat is being broken down for energy. Ketonesare formed when not enough food has been eaten to provide the energy the body needs.• The concentration of ketones is less than 1 mg/100 mL of blood. If the ketones concentration rises to higher levels, it is a warning of uncontrolled diabetes. It is easy to detect in the urine and odor can be noted on the breath.

Ketone Diagram

Ketones can be found in food

Ketone can be found Medicine and Artificial Sun Tan

• The drug cortisone is a ketone used to treat severe allergies, arthritis, asthma, multiple sclerosis, and skin conditions.

Acetone are widely used as industrial solvents

• The simplest Ketone is acetone (propanone).• It is used in nail polish remover, paints, varnishes, and resins.

Sources• http://crab.rutgers.edu/~alroche/Ch18.pdf• http://www.wiley.com/college/sc/klein/doc/Klein-ch20.pdf• http://sydney.edu.au/science/chemistry/~

george/aldehydes.html• https://

highered.mcgraw-hill.com/sites/dl/free/0073511102/562156/ch13sample.pdf

• http://www2.fiu.edu/~herriott/ch16carbonyls.pdf• http://

highered.mcgraw-hill.com/sites/dl/free/0073402621/825918/Chapter13.pdf

• http://www.scielo.br/scielo.php?pid=S0103-50532007000600003&script=sci_arttext#fig01