17«-Methylpregnenolone acetate

Deghenghi et al studied the reductive alkylation of 16-dehydropregneno-lone acetate in ammonia-tetrahydrofuran using excess lithium and alkyl iodides. Alkylation with methyl iodide followed by reacetylation of the 3-hydroxyl group affords 17a-methylpregnenolone acetate in 20% yield after purification by column chromatography. Ethyl iodide affords the 17a-ethyl analog in 40% yield, but n-propyl iodide affords the 17a-propyl compound in only a 12 % yield. 

Methyl 3a,6a-dihydroxycholanate, 240 1-Methylestrone 3-methyl ether, 10, 27 4b/3-Methyl-7-ethylenedioxy-1,2,3,4, 4a ,4b/3,5,6,7,8,10,1 Oaa-dodecahydro-phenanthrene-1 /3,4/3-diol, 236 14C-Methyl iodide, 211 ds-Methyl iodide, 210, 214 Methyl lithocholate tosylate, 329 1-Methyl-19-nortestosterone, 27 6a-Methylprednisolone, 410 6a-Methylprednisolone BMD, 410 16/3-Methylprednisone, 87 18-Methylpregn-4-ene-3/3,17a,20f-triol, 243 20-Methylpregn-5-en-3/3-ol, 415 17a-Methylpregnenolone acetate, 48 17a-Methyltestosterone, 438 16/3-Methyl- 11a,17a,21 -trihydroxy- 5 /3-pregnane-3,20-dione 21-acetate, 299, 300 20-Methyl-3/3-trityloxypregn-5-ene, 415 3/3-Methoxycholestane, 136 1-Methoxycyclohexene, 18 3-Methoxyestra-3,5(10)-diene, 18, 27... 

Deletion of the 17a-hydroxy group similarly leads to an effective topical antiinflammatory agent. Treatment of 16a-methylpregnenolone (244) (obtained by conjugate addition of an organometallic to pregnenolone) sequentially with bromine and acetate ion affords the 21 acetate, 245 (see, for example, the transformation of 196 to 198). In an interesting variation on the method for the introduction of a fluorine atom at 6, the... 

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