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Gypsetin

Prenylboration of generated in situ 3-chloroindolenine derivatives was used in synthesis of gypsetin and triptostatin B6. [Pg.447]

Possible okaramine precursors, i.e. cyclo (Trp-Trp) (20), cyclo (2-(reverse-prenyl)-Trp-Trp) (21), cyclo ( -(reverse-prenyty-Trp-Trp) (22), cyclo (2-(reverse-prenyl)-Trp-2 -(reverse-prenyl)-Trp) (23), and cyclo (7V1-(reverse-prenyl)-Trp-2 -(reverse-prenyl)-Trp) (24), were isolated during the course of the investigation of okaramine congeners [21]. Three of these compounds, 21, 22, and 24, are new compounds. cyclo(2-(Reverse-prenyl)-Trp-2 -(reverse-prenyl)-Trp) (23) was synthesized by Schkeryantz and coworkers as a precursor of gypsetin [24], but it was isolated for the first time from natural sources in our study. One year after our findings, Kozlovsky and coworkers reported the isolation of fellutanines A, B, C, and D from Penicillium fellutanum [25], which were found identical to the compounds 20, 22, and 23, respectively. [Pg.562]

Nucleophilic tert-prenylation. When using prenylboranes instead of tert-prenylboranes, tert-prenylation of 3-chloroindolenines becomes possible. The Danishefsky tert-prenylation has also been extensively used for the synthesis of 3-tert-prenylindoles which can be obtained from 2-tert-prenylated precursors (see Sect. 4). The 1995 synthesis of the acyl-CoA-cholesterol acyltransferase inhibitor gypsetin (94) [91, 92] was the first occasion to publish that elegant reaction (Scheme 19) [88, 93]. On treatment of phthalimide-protected tryptophan methyl ester (85) with tcrt-BuOCl, the 3-chloroindolenine is formed in sim, which is nucleophilicaUy attacked by prenyl-9-BBN with regioinversion of the prenyl group. Hydrazinolysis afforded 2-tert-prenyltryptophan methyl ester (91). [Pg.84]

Scheme 19 Synthesis of gypsetin by Danishefsky prenylation and oxidative cyclisation by DMDO [88]... Scheme 19 Synthesis of gypsetin by Danishefsky prenylation and oxidative cyclisation by DMDO [88]...
Danishefsky and coworkers developed a method for introducing the tcrt-prenyl group at the indole C-2 position based on C-3 chlorination followed by nucleophilic delivery of the ferf-prenyl group from a borane [99]. The intermediate was used in synthesis of gypsetin and breviamide E, both of which contain the 2-(tert-prenyl) substituent. [Pg.68]

Danishefsky and coworkers utilized a nucleophilic displacement of chloride to synthesize 2,3-disubstituted indoles and, more specifically, to realize the total synthesis of gypsetin (not shown) [34, 35]. Tryptamine derivative 68 is transformed into chloroindolenine 69 by f-butyl hypochlorite. The chloroindolenine 69 undergoes attack at C-2 by various nucleophiles, including indole, to produce, after tautomerization, the 2,3-disubstituted indoles (22-79%). The addition of a Lewis acid, Bp3-OEt2 was found to be necessary for high yields for reagents other than prenyl-9-BBN. [Pg.131]

Schkayantz JM, Woo JCG, SUiphaivanh P, Depew KM, Danishefsky SJ (1999) Total synthesis of gypsetin, deoxybrevianamide E, brevianamide E, and tryprostatin B novel constmctions of 2, 3-disubstituted indoles. J Am Chem Soc 121 11964-11975... [Pg.140]


See other pages where Gypsetin is mentioned: [Pg.765]    [Pg.74]    [Pg.129]    [Pg.130]    [Pg.570]    [Pg.571]    [Pg.571]    [Pg.84]    [Pg.120]    [Pg.140]    [Pg.112]    [Pg.113]    [Pg.615]    [Pg.1370]   
See also in sourсe #XX -- [ Pg.129 , Pg.130 ]

See also in sourсe #XX -- [ Pg.571 ]

See also in sourсe #XX -- [ Pg.84 , Pg.120 ]

See also in sourсe #XX -- [ Pg.68 ]




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Gypsetin, synthesis

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