Acetone Triamcinolone acetonide

A solution of 50 mg of 6a-fluoro-triamcinolone acetonide in 1 ml of pyridine and 1 ml of acetic anhydride is allowed to stand at room temperature for 18 hours. Removal of the reagents in vacuo gives a crystalline residue which after crystallization from acetone-hexane gives the pure 16a,17a-isopropylidene 6o -fluoro-triamcinolone 21 acetate (fluocinonide), as described in U.S. Patent 3,197,469. 

The 9,11 olefin in the intermediate (25-4) is next converted to the 9a-fluoro-11(3-hydroxy derivative (26-1) by the customary scheme. The additional unsaturation in ring A is then introduced by means of selenium dioxide to afford triamcinolone (26-2). Reaction of that compound with acetone converts the 16,17 diol to an acetal to afford triamcinolone acetonide (26-3) [21]. The latter is approximately 50 times more potent than cortisone in animal models the free glycol interestingly shows only a 2.5-fold increase in potency over the cortisone in the same model. 

Triamcinolone Acetonide is 9a-fluoro-llf3, 16a,17,21-tetrahydroxypregna-l,4-diene-3,20-dione cyclic 16,17-acetal with acetone. It is also known as 9a-fluoro-16a-hydroxyprednisolone acetonide triamcinolone 16,17-acetonide 9a-fluoro-lip,21-dihydroxy-16a,17a-isopropylidene-dioxy-1,4-pregnadiene-3,20-dione 9a-fluoro-16a, 17a-isopropylidenedioxyprednisolone. 

Triamcinolone acetonide is prepared by the reaction of acetone with triamcinolone in the presence of catalytic amounts of mineral acid Fried and Heller used perchloric acid, Bernstein hydrochloric acid. An alternative... 

To a suspension of 500 mg of 6a-fluoro-triamcinolone in 75 ml of acetone is added 0.05 milliliters of 72% perchloric acid and the mixture agitated at room temperature for 3 hours. During this period the crystals gradually dissolve and the clear solution is neutralized with dilute bicarbonate and the acetone removed in vacuo. The resulting crystalline suspension is filtered and the crystals washed with water. The dried material is recrystallized from 95% alcohol to give the pure acetonide. 

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