6-Methyl-5-hepten-2-one

Description

6-Methyl-5-hepten-2-one has a strong, fatty, green, citrus-like odor, and a bittersweet taste reminiscent of pear. May be prepared from oil of lemongrass or from citral by refluxing for 12 hours in aqueous solution containing K2C 03, and subsequent distillation and vacuum fractionation; from acetoacetic ester and methylbuten-3-ol-2 with aluminum alcoholate in Carroll’s reaction followed by pyrolysis of the ester.

Chemical properties

CLEAR SLIGHTLY YELLOW LIQUID

Chemical properties

6-Methyl-5-hepten-2-one is an important intermediate in the synthesis of terpenoids. Its odor properties are not impressive. It occurs in nature as a degradation product of terpenes. (Z)- and (E)-Tagetone, [3588-18-9], [6752-80-3], are major components of tagetes oil. Solanone [1937-54-8] and pseudoionone [141-10-6] are acyclicC13 ketoneswith a terpenoid skeleton. Solanone is one of the flavor-determining constituents of tobacco, and pseudoionone is an intermediate in the synthesis of ionones.

Chemical properties

6-Methyl-5-hepten-2-one has a strong, fatty, green, citrus-like odor and bittersweet taste reminiscent of pear.

Occurrence

Originally identified in lemongrass; it has been reported found in the essential oils of palmarosa, lemon, citronella, vervain, geranium, Ocimum canum, Artemisia scoparia, Urtica dioica and others. Also reported found in apple, apricot, sweet and sour cherry, orange juice, citrus peel oils, bilberry, lingonberry, cranberry, guava, grapes, melon, peach, pear, raspberry, strawberry, blackberry, carrot, celery, tomato, potato, clove bud and leaf, ginger, peppermint oil, thymus, Gruyere cheese, butter, beef, hop oil, beer, cognac, cider, white wine, cocoa, tea, peanut oil, avocado, Arctic bramble, cloudberry, olive, passion fruit, plumcot, rose apple, marjoram, starfruit, mango, fig, rice, rice bran, quince, origanum, calamus, buckwheat, corn oil, wort, dried bonito, elderberry, cherimoya, kiwifruit, mountain papaya, endive, lemon balm, clary sage, nectarine, clam, Cape gooseberry, maté, German chamomile oil and mastic gum leaf oil, lime oil and apple brandy

The Uses of 6-Methyl-5-hepten-2-one

Organic synthesis, inexpensive perfumes, fla-voring.

The Uses of 6-Methyl-5-hepten-2-one

6-Methyl-hepten-2-one is used in the synthesis of thyrsiferyl 23-Acetate which acts as an anti-leukemic inducer of apoptosis.

Definition

ChEBI: A heptenone that is hept-5-en-2-one substituted by a methyl group at position 6. It is a volatile oil component of citronella oil, lemon-grass oil and palmarosa oil.

Preparation

From oil of lemongrass or from citral by refluxing for 12 hours in aqueous solution containing K2CO3, and subsequent distillation and vacuum fractionation; from acetoacetic ester and methyl-buten-3-ol-2 with aluminum alcoholate in Carroll’s reaction followed by pyrolysis of the ester

Aroma threshold values

Detection: 50 ppb

Taste threshold values

Taste characteristics at 10 ppm: green, vegetative, musty, apple, banana and green bean-like.

Synthesis Reference(s)

Tetrahedron Letters, 28, p. 4893, 1987 DOI: 10.1016/S0040-4039(00)96654-1
Synthesis, p. 796, 1981 DOI: 10.1055/s-1981-29599

General Description

6-Methyl-5-hepten-2-one is one of the main flavor volatile of tomatoes.

Flammability and Explosibility

Flammable

Safety Profile

Moderately toxic by ingestion. A skin irritant. Flammable liquid when exposed to heat, sparks, or flame. When heated to decomposition it emits acrid smoke and irritating fumes.