Fluorometholone

1.9,11-Epoxy Reaction

Add 10g of 6-methyl-17-hydroxy-1,4,9-trien-pregn-3,20-dione and 120ml of acetone to a reaction flask, stir, cool to 0℃, add 9g of NBS over 30 minutes, maintain the reaction at 5-10℃ for 2 hours, add 10% sodium carbonate aqueous solution to neutralize to pH=6.5, raise the temperature to 20±2℃, add 15ml of 10% sodium hydroxide aqueous solution over 1 hour, maintain the temperature at 20-25℃ for 2 hours, neutralize to pH=7 with acetic acid, concentrate under reduced pressure until there is no acetone odor, dilute to ice water, filter, dry to obtain 11.2g of 9,11-epoxide.

2.9,11-Ring-opening reaction

Add 11.2g of 9,11-epoxide obtained from the reaction of 9,11-epoxide and 60ml of DMF to a reverse flask, stir, cool to -5℃, introduce hydrogen fluoride gas, maintain the reaction at -5～0℃ for 1 hour, dilute in ice water, adjust the pH to 7 with ammonia, filter, dry, and obtain 9.5g of fluorometholone. Recrystallize in acetone to obtain 8.5g of fluorometholone, MP: 290-300℃.

Refining:

Add 100g of crude fluorometholone (97%) to 400mL of N,N-dimethylformamide, stir and heat to 80-90℃, maintain for 0.5h, until completely dissolved, then slowly add 1L of anhydrous methanol, maintaining the temperature within the range of 60-70℃ throughout the addition process. After addition, maintain for 0.5h, then cool to 0-5℃ and maintain at 0-5℃ for crystallization for 12h. Filter to obtain off-white crystalline fluorometholone concentrate, dry to obtain 30g of fluorometholone concentrate (purity 99.55%, known single impurities 0.14%, total impurities 0.09%).

Fluorometholone is the topical synthetic glucocorticoid. Its tropical anti-inflammatory effect is 40 times as much as hydrocortisone, but their effects of oral administration are almost equal. It is mainly used for local treatment of skin allergy, pruritus, rash and other diseases related to allergy. Oral administration is also used for the treatment of breast cancer, childhood leukemia, connective tissue disease, and so on.

It is mainly the topical medication for various skin diseases that are suitable for glucocorticoid treatment, for allergic and inflammatory eye diseases, and for breast cancer and childhood leukemia.

1. The adverse reaction of this drug is similar to that of other glucocorticoid hormones, but the degree is lighter. The transocular administration of this drug can cause irritation of local burning sensation and foreign body sensation. Long-term use of this drug can cause the increase of intraocular pressure and even glaucoma. It can occasionally cause optic nerve damage, subcapsular cataract, secondary ocular tissue fungal and virus infection, perforation of eyeball and delayed wound healing, 
2. Cross allergy: People allergic to other adrenocortical hormone drugs may also be allergic to this drug.
3. Contraindications: Allergic to glucocorticoid, acute superficial herpes simplex viral keratitis, varicella, cowpox and most other viral infections, ocular fungal infection and ophthalmic tuberculosis.
4. Cautious use: Any person who suffers the pathological changes that can make the cornea and sclera thinner or who have a history of herpes simplex viral keratitis, pregnant women and breast-feeding women.

White powder

Oxylone, Upjohn, US,1959

Fluorometholone is a glucocorticoid; anti-inflammatory.

ChEBI: A member of the class of glucocorticoids that is Delta1-progesterone substituted at positions 11beta and 17 by hydroxy groups, at position 6alpha by a methyl group and at position 9 by a fluoro group. Used for the treatment of corticosteroid-responsive inflammation of the palpebral and bulbar conjunctiva, cornea and anterior segment of the globe.

The following description is taken from US Patent 2,867,637.
(a) Preparation of 6α-Methyl-9α-Fluoro-11β,17α,21-Trihydroxy-1,4Pregnadiene-3,20-Dione 21-Methanesulfonate: A solution was prepared containing 250 mg of 1-dehydro-6α-methyl-9α-fluorohydrocortisone [G.B. Spero et al, J. Am. Chem. Soc.79, 1515 (1957)] in 6 ml of pyridine. This solution was cooled to 0°C and treated with 0.25 ml of methanesulfonyl chloride. Thereafter the solution was allowed to stir at a temperature between 0° and 5°C for a period of 18 hours. Thereafter ice and 2 ml of water were added, followed by 30 ml of sufficient dilute (5%) hydrochloric acid to neutralize the pyridine. The mixture was then filtered, the precipitate washed with water and dried to give 197 mg of crude 6α-methyl-9α-fluoro11β,17α,21-trihydroxy-1,4-pregnadiene-3,20-dione 21-methanesulfonate of MP 165° to 185°C.
(b) Preparation of 6α-Methyl-9α-Fluoro-11β,17α-Dihydroxy-21-Iodo-1,4Pregnadiene-3,20-Dione: The crude 197 mg of methanesulfonate of 6αmethyl-9α-fluoro-11β,17α,21-trihydroxy-1,4-pregnadiene-3,20-dione was dissolved in 5 ml of acetone and treated with a solution of 197 mg of sodium iodide in 5 ml of acetone. The mixture was heated under reflux with stirring for a period of 15 minutes. The heating was then discontinued and the mixture concentrated to dryness at reduced pressure to give 6α-methyl-9αfluoro-11β,17α-dihydroxy-21-iodo-1,4-pregnadiene-3,20-dione.
(c) Preparation of 6α-Methyl-9α-Fluoro-11β,17α-Dihydroxy-1,4-Pregnadiene3,20-Dione: The crude 6α-methyl-9α-fluoro-11β,17α-dihydroxy-21-iodo-1,4pregnadiene-3,20-dione was slurried with 5 ml of acetic acid and stirred for a period of 45 minutes. Thereafter was added a solution of 250 mg of sodium thiosulfate pentahydrate in 5 ml of water causing the iodine color to disappear. Additional water was added (30 ml) and the reaction mixture was filtered. The resulting solid precipitate was washed with water and dried to give 146 mg of crude 6α-methyl-9α-fluoro-11β,17α-dihydroxy-1,4pregnadiene-3,20-dione.
The crude material was then chromatographed by dissolving 120 mg of 6αmethyl-9α-fluoro-11β,17α-dihydroxy-1,4-pregnadiene-3,20-dione in 300 ml of methylene chloride and allowing the thus obtained solution to be absorbed by a chromatographic column containing 10 grams of Florisil anhydrous magnesium silicate. The column was developed taking fractions of 20 ml each as follows:Fractions 11 through 24 inclusive were combined, evaporated and twice recrystallized from acetone to give pure 6α-methyl-9α-fluoro-11β,17αdihydroxy-1,4-pregnadiene-3,20-dione of melting point 292° to 303°C.

Flarex (Alcon).

Glucocorticoid, Antiinflammatory

Fluorometholone, 9-fluoro-11β,17-dihydroxy-6α-methylpregn-4-ene-3,20-dione(Fluor-Op, FML), lacks the typical C21 OH group of GCsand is used exclusively in ophthalmic products. The 17-acetateof fluorometholone is also used as an ophthalmic suspension(Flarex).

Clinically significant in allergic conjunctivitis and as anti-inflammatory following cataract surgery.