The Selective Hydrolysis of Steroidal Acetates on Alumina

Johns, William F.; Jerina, Donald M.

doi:10.1021/jo01045a535

Cited by 13 publications

(9 citation statements)

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“…We then examined the selectivity among a primary acetate and a secondary acetate for betulin diacetate (11). It should be noted that both the primary acetate and the secondary acetate in compound 11 have a similar quaternary carbon residing next to them.…”

Section: Resultsmentioning

confidence: 99%

“…BF 3 ·Et 2 O in wet acetonitrile and Bu 3 SnOMe in ClCH 2 CH 2 Cl have been found to cleave anomeric acetates in the presence of alkyl acetates. Lipase from Candida cylindracea and Al 2 O 3 in benzene are also reported to be effective agents for deacylation of primary acetates. Other conditions for selectively removing primary acetates include KCN in EtOH, 5% KOH in methanol, and K 2 CO 3 in methanol and water .…”

Section: Introductionmentioning

confidence: 99%

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A Reagent for Selective Deprotection of Alkyl Acetates

Bizuneh

Walker

1996

J. Org. Chem.

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The use of magnesium methoxide for selective deprotection of alkyl esters is described. By adjusting the equivalents of the magnesium methoxide reagent, it is possible to selectively cleave primary acetate in the presence of secondary and tertiary acetate and to cleave secondary acetate in the presence of tertiary acetate. A high selectivity can also be obtained for the same primary acetates if the β-positions of the acetates render a different steric bulkiness. This mild reagent has been successfully applied to the selective deprotection of many natural-occurring molecules including hydroxycitronnellol diacetate, trans-sobrerol diacetate, betulin diacetate, and baccatin III.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Reagent for Selective Deprotection of Alkyl Acetates

Bizuneh

Walker

1996

J. Org. Chem.

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“…An NMR spectrum showed identifiable peaks at 0.79 and 1.03 (18-and 19-methyl), 2.01 (CH,COO-), 3.68 (-COOCH,), and 5.41 (> C = CH--), PPm.…”

Section: As-furostene-3t9-ol-26-oic Acid 3-acetate (3)mentioning

confidence: 99%

“…An NMR spectrum**** showed identifiable peaks at 0.82 and 1.07 (18and 19-methyl), 2.05 (CH,COO-), 3 * Woelm, Eschwege, Germany. Reference to a company or product name does not imply approval or recommendation of the product by the U. S. Department of Agriculture to the exclusion of others that may be suitable.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of kryptogenin‐26‐¹⁴C and diosgenin‐26‐¹⁴C

Bennett

Sauer

Heftmanń

1969

J. Labelled Cpd. Radiopharm.

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“…Acetylation of the mixture furnished nontoxic diacetates, which could be chromatographically separated. Hydrolysis of the acetates on alumina under mild conditions 10 proved that the structural integrity of the molecules had been preserved. In normal practice we carried out all subsequent work with the reasonably stable diacetates or even more conveniently, with the monomethyl ether monoacetates.…”

Section: Introductionmentioning

confidence: 99%