The Experts below are selected from a list of 60 Experts worldwide ranked by ideXlab platform
Barbara Zajc - One of the best experts on this subject based on the ideXlab platform.
-
Synthesis of (±)-trans-7,8-Dihydrodiol of 6-Fluoro-benzo[a]pyrene via Hydroxyl-Directed Regioselective Functionalization of Substituted Pyrene
The Journal of organic chemistry, 1999Co-Authors: Barbara ZajcAbstract:Synthesis of (±)-trans-7,8-dihydroxy-6-fluoro-7,8-dihydrobenzo[a]pyrene, the metabolite from 6-fluoro-benzo[a]pyrene, is described. Position 6 of 7,8,9,10-tetrahydrobenzo[a]pyren-7-ol (1) was functionalized by bromination with N-bromosaccharin. Regioselectivity in the bromination is thought to derive from a substrate−reagent hydrogen bond. NMR evidence is offered to support this model. The 6-bromo derivative 2 was subjected to dehydration followed by bromine−lithium exchange. Quenching the lithio intermediate with NFSi afforded the 6-fluoro derivative 4. Prevost Reaction on the 7,8 double bond resulted in the trans dibenzoate 5 (established by comparison to a cis derivative prepared by osmium tetroxide cis dihydroxylation). Introduction of the 9,10 double bond by a bromination−dehydrobromination procedure, followed by hydrolysis, gave racemic trans-7,8-dihydrodiol 7. Resolution of the enantiomers was achieved by chiral HPLC, and the absolute configurations of the early and late eluting isomers were determ...
Girish K Trivedi - One of the best experts on this subject based on the ideXlab platform.
-
woodward Prevost Reaction on diosgenin and its hydroxy analogue characterisation and possible mechanism for the formation of unusual products
Journal of Chemical Research-s, 1998Co-Authors: Rita Katoch, M H A Baig, Girish K TrivediAbstract:Woodward–Prevost Reaction on diosgenin and its 4β-hydroxy derivative yielded polyhydroxy steroids, 6–8 and rearranged diosphenol 9 and aldehyde 10; a plausible mechanism involved in their formation is described.
-
Woodward–Prévost Reaction on Diosgenin and its Hydroxy Analogue: Characterisation and Possible Mechanism for the Formation of Unusual Products
Journal of Chemical Research, 1998Co-Authors: Rita Katoch, M H A Baig, Girish K TrivediAbstract:Woodward–Prevost Reaction on diosgenin and its 4β-hydroxy derivative yielded polyhydroxy steroids, 6–8 and rearranged diosphenol 9 and aldehyde 10; a plausible mechanism involved in their formation is described.
Ki Hun Park - One of the best experts on this subject based on the ideXlab platform.
-
α-Rhamnosidase inhibitory activities of polyhydroxylated pyrrolidine
Bioorganic & medicinal chemistry letters, 2005Co-Authors: Jin Hyo Kim, Marcus J. Curtis-long, Woo Duck Seo, Jin Hwan Lee, Byong Won Lee, Yong‐jin Yoon, Kyu Young Kang, Ki Hun ParkAbstract:Abstract We designed and synthesized polyhydroxylated pyrrolidines 1 – 12 from l -tyrosine, l -phenylalanine, and d -tyrosine through iodine-mediated intramolecular cyclization followed by Woodward–Prevost Reaction. The synthetic polyhydroxylated pyrrolidines were identified with structure-based inhibitory activity and selective inhibitory activity against α-rhamnosidase. (2 S ,3 S ,4 R )-deacetyl anisomycin 7 was the best inhibitor among the 12 polyhydroxylated pyrrolidines because it possesses the same stereoconfiguration at C1, C2, C3 as α- l -rhamnopyranoside. An investigation into the nature of the inhibition showed that the synthetic pyrrolidines are competitive inhibitors. They also did not have remarkable inhibitory activity against seven glycosidases (α-glucosidase, α-mannosidase, α-amylase, β-glucosidase, β-galactosidase, β-amylase, and invertase).
-
Stereodivergent and Regioselective Synthesis of 3,4-cis- and 3,4-trans-Pyrrolidinediols from α-Amino Acids
Organic letters, 2004Co-Authors: Jin Hyo Kim, Marcus J. C. Long, Jun Young Kim, Ki Hun ParkAbstract:Highly stereodivergent Woodward−Prevost Reaction applied to iodoacetates derived from homochiral α-amino acids afforded enantiopure 3,4-cis- and 3,4-trans-pyrrolidinediol derivatives, with control over the protecting group, allowing for differential protection.
Yi Yi Myint - One of the best experts on this subject based on the ideXlab platform.
-
Preparation of α-Iodoacetates from Alkenes by Co(OAc)2 Catalyzed Woodward-Prevost Reaction.
ChemInform, 2004Co-Authors: Yi Yi Myint, Mohamed Afzal PashaAbstract:Woodward-Prevost Reaction of alkenes with iodine and cobalt(II) acetate in acetic acid is reported. The Reaction is facile and α-iodoacetates are obtained from both acyclic and cyclic alkenes in high yields within 15-55 min
-
Preparation of α‐Iodoacetates from Alkenes by Co(OAc)2 Catalyzed Woodward‐Prevost Reaction
'Wiley', 2004Co-Authors: Yi Yi MyintAbstract:Woodward-Prevost Reaction of alkenes with iodine and cobalt(II) acetate in acetic acid is reported. The Reaction is facile and α-iodoacetates are obtained from both acyclic and cyclic alkenes in high yields within 15-55 min
Sukekatsu Nozaki - One of the best experts on this subject based on the ideXlab platform.
-
A New Synthesis of cis-Diol from Alkene Using Iodine-Ammonium Cerium(IV) Nitrate
Synthesis, 2005Co-Authors: C. Akira Horiuchi, Gong Dan, Masaki Sakamoto, Kazuhiko Suda, Shigeru Usui, Okihiko Sakamoto, Shinya Kitoh, Satoshi Watanabe, Takamitsu Utsukihara, Sukekatsu NozakiAbstract:The Reaction mixtures of 5a-cholest-2-ene with iodine-ammonium cerium(IV) nitrate [CAN(IV)] were converted with potassium hydroxide in methanol-water to give the more hindered 2p,3p-diol in high yield. Cyclohexene and cycloheptene similarly reacted to the corresponding cis-diols in good yield. It was found that this Reaction intermediate proceeds to give trans-iodoacetate via trans-iodonitrate. This new synthetic method provided several advantages over the Prevost Reaction.