𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Synthesis of dexamethasone-4-14C

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

Publisher
John Wiley and Sons
Year
1982
Tongue
French
Weight
498 KB
Volume
19
Category
Article
ISSN
0022-2135

No coin nor oath required. For personal study only.

✦ Synopsis

Abstract

The bismethylenedioxy (BMD) derivative of dexamethasone 2 was silylated with trimethylchlorosilane and imidazole in dimethylformamide to give the 11β‐trimethylsilyloxy BMD derivative 3. The Δ^1^ ‐double bond in 3 was hydrogenated over 5% palladium on carbon to give the Δ^4^‐3‐oxo steroid 4. Oxidation of 4 with potassium permanganate‐sodium metaperiodate gave the seco‐acid 5 which on subsequent treatment with acetic anhydride; sodium acetate and triethylamine gave the enol‐lactone 6. The enol‐lactone 6 was reacted with ^14^C‐methylmagnesium iodide to give an adduct 7a which on heating at reflux with lithium 2,6‐di‐t‐butylphenoxide in dioxane gave the Δ^4^‐3‐oxo derivative 8. Compound 8 was heated at reflux with m‐iodylbenzoic acid and diphenyl diselenide in toluene to give the Δ^1,4^‐3‐oxo steroid 9. The protecting BMD and silyl groups were removed in a single step by reaction with aqueous trifluoroacetic acid containing 2N hydrochloric acid at room temperature to give dexamethasone‐4‐^14^C 10.

📜 SIMILAR VOLUMES

Synthesis of [4-14C]fluasterone
Synthesis of [4-14C]fluasterone
✍ Mingcheng Han; Bruce N. Diel; Peter J. Deardorff; David B. Boaz 📂 Article 📅 2007 🏛 John Wiley and Sons 🌐 French ⚖ 72 KB
Synthesis of [4-14C]diosgenin
Synthesis of [4-14C]diosgenin
✍ E. S. Ferdinandi 📂 Article 📅 1979 🏛 John Wiley and Sons 🌐 French ⚖ 211 KB

## Abstract [4‐^14^C]‐(25R)‐Spirost‐5‐en‐3β‐ol(diosgenin)__l__, specific activity 3.77 ± 0.02 mCi/mmole, was synthesized in four stees from (25R)‐5‐hydroxyspirost‐5‐en‐3‐oic‐3,5‐lactone 4 and [^14^C] methyl magnesium iodide with an overall yield of 18%. The preparation of the starting lactone from

Synthesis of [4-14C]theophylline
Synthesis of [4-14C]theophylline
✍ Michael G. Williams; Albert M. Mattocks 📂 Article 📅 1981 🏛 John Wiley and Sons 🌐 English ⚖ 206 KB
Synthesis of [4-14C]-pelargonidin chlori
Synthesis of [4-14C]-pelargonidin chloride and [4-14C]-delphinidin chloride
✍ Michael Kraus; Ellen Biskup; Elke Richling; Peter Schreier 📂 Article 📅 2006 🏛 John Wiley and Sons 🌐 French ⚖ 157 KB 👁 1 views

The synthesis of [4-14 C]-pelargonidin chloride and [4-14 C]-delphinidin chloride via [formyl-14 C]-2-(benzoyloxy)-4,6-dihydroxybenzaldehyde, o,4-diacetoxyacetophenone and o,3,4,5-tetraacetoxyacetophenone is described. The first step comprised labelling of the carbonyl group of 2-(benzoyloxy)-4,6-di

Synthesis of triamcinolone acetonide-4-1
Synthesis of triamcinolone acetonide-4-14C
✍ Pemmaraju Narasimha Rao; James W. Cessac; Kenneth A. Hill 📂 Article 📅 1982 🏛 John Wiley and Sons 🌐 French ⚖ 492 KB

## 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**