Synthesis of triamcinolone acetonide-4-14C

✍ Scribed by Pemmaraju Narasimha Rao; James W. Cessac; Kenneth A. Hill

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: French
• Weight: 492 KB
• Volume: 19
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/jlcr.2580191002

✦ Synopsis

Abstract

The free hydroxyl groups in triamcinolone acetonide (1) were protected as silyl ethers to give the bis‐silyloxy derivative 4. Compound 4 was then hydrogenated over 5% palladium on carbon to give the Δ^4^‐3‐oxo steroid 5 which was then converted to the enol‐lactone 7 under selective reaction conditions. The enol‐lactone 7 was subjected to Grignard reaction with ^14^C‐methylmagnesium iodide to give an adduct 8a which on subsequent treatment with lithium 2,6‐di‐t‐butylphenoxide gave 4‐^14^C‐Δ^4^‐3‐oxo derivative 9. Compound 9. was heated with selenium dioxide in t‐butanol containing pyridine to give the Δ^1,4^‐3‐oxo derivative 10. Removal of the silyl protecting groups was readily accomplished by heating 10 with hydrochloric acid in methanol‐tetrahydrofuran solution to give the title compound 11.