scholarly journals Rate Enhancement of Acid-Catalyzed Alcohol Dehydration by Supramolecular Organic Capsules

ACS Catalysis ◽  
2020 ◽  
Vol 10 (22) ◽  
pp. 13371-13376
Author(s):  
Wei Zhang ◽  
Guanhua Cheng ◽  
Gary L. Haller ◽  
Yue Liu ◽  
Johannes A. Lercher
Keyword(s):  
Alcohol Dehydration ◽  
Rate Enhancement ◽  
Acid Catalyzed

Acid-catalyzed cyclization of terpenoids in a micellar system. Selectivity and rate enhancement in the cyclization of citronellal

1984 ◽  
Vol 49 (23) ◽  
pp. 4557-4559 ◽  
Author(s):  
Benjamin C. Clark ◽  
Theresa S. Chamblee ◽  
Guillermo A. Iacobucci
Keyword(s):  
Micellar System ◽  
Rate Enhancement ◽  
Acid Catalyzed

Water Soluble Steroids with Catalytic Substituents II. Synthesis of 3β-(4(5)-Imidazolyl)-5α-androstane-11β, 17β,-diamine and Comparison of its Catalytic Properties with Those of 17β-(4(5)-Imidazolyl)-5α-androstane-3β, 11β-diamine

1973 ◽  
Vol 51 (23) ◽  
pp. 3936-3942 ◽  
Author(s):  
J. Peter Guthrie ◽  
Yasutsugu Ueda
Keyword(s):  
Catalytic Properties ◽  
Lead Tetraacetate ◽  
Water Soluble ◽  
Keto Group ◽  
Rate Enhancement ◽  
Multistep Process ◽  
Acid Catalyzed ◽  
Hydrolysis Of

3β-(4(5)-Imidazolyl)-5α-androstane-11β,17β-diamine, 15, has been synthesized in a multistep process from adrenosterone, 2, starting with lithium ammonia reduction to give 11α,17β-dihydroxy-5α-androstan-3-one, 3, which was converted to its diacetate, 4. Ethynylation at the 3 keto group gave the ethynyl triol 5, purified as its11,17-diacetate 6. Acid catalyzed rearrangement of 6 gave 3-acetyl-5α-androst-2-ene-11α,17β-diol diacetate, 7. This was hydrogenated, and then subjected to base catalyzed hydrolysis and equilibration to give crystalline 3β-acetyl-5α-androstane-11α,17β-diol, 9, which was converted to 3β-acetoxyacetyl-5α-androstane-11α,17β-diol, 10, using lead tetraacetate. After hydrolysis to the triol, 11, the Weidenhagen reaction led to formation of 3β-imidazolyl-5α-androstane-11α,17β-diol, 12. Finally oxidation to the dione, 13, formation of the dioxime, 14, and hydrogénation give 15. As expected 15 is a better catalyst than 17β-(4(5)-imidazolyl-5α-androstane-3β,11β-diamine, 1, for the hydrolysis of aryl esters of acids with hydrophobic substituents, but the effect is small. With 1 there is a marked electrostatic rate enhancement or retardation when charged groups are present on the aryl esters; this effect is much smaller for 15.

Acid Catalyzed Furan Ring Transposition

10.1039/sp768 ◽  
2014 ◽  
Author(s):  
Jamsheena V. ◽  
Ravindra Phatake
Keyword(s):  
Furan Ring ◽  
Acid Catalyzed
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