Etretinate

Chemical Properties

Crystalline Solid

Originator

Tigason,Roche,UK,1981

Uses

Aromatic analog of Retinoic Acid. Immunomodulator. Antipsoriatic.

Definition

ChEBI: Etretinate is a retinoid, an enoate ester and an ethyl ester. It has a role as a keratolytic drug.

Manufacturing Process

228 g of 5-(4-methoxy-2,3,6-trimethylphenyl)-3-methyl-penta-2,4-diene-1- triphenylphosphonium bromide are introduced under nitrogen gassing into 910 ml of dimethylformamide and treated with cooling at 5°C to 10°C within 20 minutes with 17.5 g of a suspension of sodium hydride (about 50% by weight) in mineral oil. The mixture is stirred for 1 hour at about 10°C, then treated at 5°C to 8°C dropwise with 61.8 g of 3-formylcrotonic acid butyl ester, heating for 2 hours at 65°C, subsequently introduced into 8 liters of ice water, and, after the addition of 300 g of sodium chloride, thoroughly extracted with a total of 18 liters of hexane. The extract is washed 5 times with 1 liter of methanol/water (6:4 parts by volume) each time and 2 times with 1.5 liter of water each time, dried over sodium sulfate and evaporated under reduced pressure to leave 9-(4-methoxy-2,3,6-trimethylphenyl)-3,7- dimethyl-nona-2,4,6,8-tetraen-1-oic acid butyl ester, MP 80°C to 81°C as the residue.
125.8 g of 9-(4-methoxy-2,3,6-trimethylphenyl)-3,7-dimethyl-nona-2,4,6,8- tetraen-1-oic acid butyl ester are introduced into 2,000 ml of abs. ethanol and treated with a solution of 125.8 g of potassium hydroxide in 195 ml of water. The mixture is heated to boiling under nitrogen gassing for 30 minutes, then cooled, introduced into 10 liters of ice water and, after the addition of about 240 ml of concentrated hydrochloric acid (PH 2-4), thoroughly extracted with a total of 9 liters of methylene chloride. The extract is washed with about 6 liters of water to neutrality, dried over calcium chloride and evaporated under reduced pressure. The residue is taken up in 700 ml of hexane. The precipitated 9-(4-methoxy-2,3,6-trimethylphenyl)-3,7-dimethyl-nona-2,4,6,8- tetraen-1-oic acid melts at 228°C to 230°C.
60 g of 9-(4-methoxy -2,3,6-trimethylphenyl )-3,7-dimethyl-nona-2,4,6 8- tetraen-1-oic acid are dissolved in 1,000 ml of acetone. After the addition of 128 g of ethyl iodide and 128 g of potassium carbonate, the solution is stirred under nitrogen gassing for 16 hours at 55°C to 60°C and subsequently
evaporated under reduced pressure. The residue is dissolved in 1,300 ml of petroleum ether (BP 80°C to 105°C). The 9-(4-methoxy-2,3,6- trimethylphenyl)-3,7-dimethyl-nona-2,4,6,8-tetraen-1-oic acid ethyl ester crystallizing out at -20°C, melts at 104°C to 105°C.

brand name

Tegison (Roche);Ro 10-9359;Tigasan.

Therapeutic Function

Antipsoriatic, Antitumor

World Health Organization (WHO)

Etretinate, a retinol derivative, was introduced in 1981 for the treatment of psoriasis. Its use in pregnant women has resulted in major foetal abnormalities. The manufacturer's information emphasizes that the drug is teratogenic and must not be given to women who are pregnant, and that contraceptive measures must be maintained for at least two years after discontinuation of treatment. In some countries, blood banks are advised not to accept as donors persons who have taken etretinate within the previous year.