Betamethasone 21-acetate Chemical Properties

Melting point:

200-220°C (dec.)

alpha 

D +140° (chloroform)

Boiling point:

579.4±50.0 °C(Predicted)

Density 

1.0932 (rough estimate)

refractive index 

1.5980 (estimate)

storage temp. 

Refrigerator

solubility 

Practically insoluble in water, freely soluble in acetone, soluble in ethanol (96 per cent) and in methylene chloride. It shows polymorphism (5.9).

pka

12.08±0.70(Predicted)

color 

White to Off-White

Water Solubility 

30mg/L(25 ºC)

Merck 

14,1180

CAS DataBase Reference

987-24-6(CAS DataBase Reference)

EPA Substance Registry System

.beta.-Methasone acetate (987-24-6)

Safety Information

Hazard Codes 

Xn

Risk Statements 

40

Safety Statements 

22-36

WGK Germany 

3

HS Code 

2937220000

Betamethasone 21-acetate Usage And Synthesis

Chemical Properties

White Solid

Originator

Celestone Soluspan,Schering,US,1965

Uses

Betamethasone acetate (BA)

Uses

amino acid, nutrient

Uses

CORTICOSTEROID

Definition

ChEBI: Betamethasone acetate is an acetate ester, a steroid ester, a fluorinated steroid, a 17alpha-hydroxy steroid, a 20-oxo steroid, an 11beta-hydroxy steroid, a 3-oxo-Delta(1),Delta(4)-steroid and a tertiary alpha-hydroxy ketone. It is functionally related to a betamethasone.

Manufacturing Process

The synthesis is long and complex. For brevity, only the last steps are given here. Refer to the patents cited below for full details.
Preparation of 9α-Bromo-11β,17α,21-Trihydroxy-16β-Methyl-4-Pregnene-3,20- Dione 21-Acetate: To a mixture of 620 mg of 17α,21-dihydroxy-16β-methyl- 4,9(11)-pregnadiene-3,20-dione 21-acetate and 330 mg of Nbromosuccinimide in 10 ml of dioxane and 3.2 ml of water cooled to 10°C was added 1.8 ml of cold 1 M aqueous perchloric acid. The mixture was stirred at 15°C for 3 hours. Excess N-bromosuccinimide was destroyed by addition of aqueous sodium thiosulfate and most of the dioxane was removed in vacuo. About 30 ml of water was added and crystalline bromohydrin, 9α-bromo- 11β,17α,21-trihydroxy-16β-methyl-4-pregnene-3,20-dione 21-acetate, was filtered, washed with water, and dried in air. Preparation of 9β,11β-Epoxy-17α-21-Dihydroxy-16β-Methyl-4-Pregnene-3,20- Dione 21-Acetate: To a stirred solution of 100 mg of the 9α-bromo- 11β,17α,21-trihydroxy-16β-methyl-4-pregnene-3,20-dione 21-acetate in 3 ml of tetrahydrofuran and 1 ml of methanol under nitrogen was added 1.02 ml of 0.215N methanolic sodium methoxide. After 10 minutes at 25°C, 0.2 ml of acetic acid was added and the methanol removed in vacuo. The residue was acetylated with 1.00 ml of pyridine and 0.5 ml of acetic anhydride at 60°C for 70 minutes. The mixture was taken to dryness in vacuo, water added, and the product extracted into chloroform. The residue was crystallized from etheracetone to give pure 9β,11β-epoxy-17α,21-dihydroxy-16β-methyl-4-pregnene- 3,20-dione 21-acetate.
Preparation of 9α-Fluoro-11β,17α,21-Trihydroxy-16β-Methyl-4-Pregnene-3,20- Dione 21-Acetate: To a solution of 200 mg of 9β,11β-epoxy-17α,21-dihydroxy- 16β-methyl-4-pregnene-3,20-dione 21-acetate in 2 ml of chloroform and 2 ml of tetrahydrofuran in a polyethylene bottle at -60°C was added 2 ml of a 2:1 (by weight) mixture of anhydrous hydrogen fluoride and tetrahydrofuran. After 4 hours at -10°C the mixture was cooled to -60°C and cautiously added to a stirred mixture of 30 ml or 25% aqueous potassium carbonate and 25 ml of chloroform kept at -5°C. The aqueous phase was further extracted with chloroform and the latter phase washed with water and dried over magnesium sulfate. The residue on crystallization from acetone-ether gave pure 9α-fluoro- 11β,17α,21-trihydroxy-16β-methyl-4-pregnene-3,20-dione 21-acetate.
Preparation of 9α-Fluoro-11β,17α,21-Trihydroxy-16β-Methyl-4-Pregnadiene- 3,20-Dione 21-Acetate 100 mg of 9α-fluoro-11β,17α,21-trihydroxy-16β- methyl-4-pregnene-3,20-dione 21-acetate was treated with selenium dioxide to produce the corresponding 9α-fluoro-11β,17α,21-trihydroxy-16β-methyl-4- pregnadiene-3,20-dione 21-acetate. Alternately, Bacillus sphaericus may be utilized.

Therapeutic Function

Glucocorticoid

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