Hydrochloric Acid → Dexamethasone mesylate

HRID 2117242Notes

Reaction equation

[CH3:1][C@H:2]1[C@:19]([OH:24])([C:20]([CH2:22][OH:23])=[O:21])[C@:18]2([CH3:25])[C@H:4]([C@H:5]3[C@:15]([F:27])([C@@H:16]([OH:26])[CH2:17]2)[C@:14]2([CH3:28])[C:8](=[CH:9][C:10]([CH:12]=[CH:13]2)=[O:11])[CH2:7][CH2:6]3)[CH2:3]1.[CH3:29][S:30](Cl)(=[O:32])=[O:31].Cl>N1C=CC=CC=1>[CH3:1][C@H:2]1[C@:19]([OH:24])([C:20]([CH2:22][OH:23])=[O:21])[C@:18]2([CH3:25])[C@H:4]([C@H:5]3[C@:15]([F:27])([C@@H:16]([OH:26])[CH2:17]2)[C@:14]2([CH3:28])[C:8](=[CH:9][C:10]([CH:12]=[CH:13]2)=[O:11])[CH2:7][CH2:6]3)[CH2:3]1.[S:30]([O-:32])(=[O:11])(=[O:31])[CH3:29]

Participants

Conditions

Temperature: 0 °C

Procedure

A 200 ml Erlenmeyer flask equipped with a magnetic stir bar and a rubber septum was charged with 5 grams of dexamethasone (12.7 mmol, 1 equivalent) and 16 ml of anhydrous pyridine. The flask was cooled to 0° C. with an ice bath, and 1.2 ml of methanesulfonyl chloride was added. After 1 hour, 0.8 ml of additional methanesulfonyl chloride was added. At two hours, the solution was poured into 100 ml of cold 1M HCl, forming a precipitate. The precipitate was filtered and redissolved in 250 ml of ethanol, and precipitated into 250 ml of 1M HCl. The precipitate was filtered and recrystallized in ethanol, filtered, and dried under vacuum yielding 4.95 g (82.6%) of dexamethasone mesylate.

Workup

customA 200 ml Erlenmeyer flask equipped with a magnetic stir bar
waitAt two hours
customforming a precipitate
filtrationThe precipitate was filtered
dissolutionredissolved in 250 ml of ethanol
customprecipitated into 250 ml of 1M HCl
filtrationThe precipitate was filtered
customrecrystallized in ethanol
filtrationfiltered
customdried under vacuum

Sources & evidence

ORD record: ord-668589db6e124fb5bee90f0ab6d63b7e
Source dataset: uspto-grants-2008_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07442386B2

Reaction notes

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