Silyl Triflate-Mediated Ring-Closure and Rearrangement in the Synthesis of Potential Bisfuran-Containing Intermediates of Aflatoxin Biosynthesis
作者:Todd L. Graybill、Eduard G. Casillas、Kollol Pal、Craig A. Townsend
DOI:10.1021/ja990591x
日期:1999.9.1
strategy is described involving two silyl triflate-mediated cyclization and rearrangement processes that have enabled both furofuran oxidation states to be readily achieved and undesired but thermodynamically favorable side reactions to be avoided in the preparation of these ring systems. In the first an o-methoxymethyl phenylacetaldehyde is cyclized directly to the five-membered, differentially protected
NOVEL MACROCYCLIC INHIBITORS OF HEPATITIS C VIRUS REPLICATION
申请人:Seiwert Scott D.
公开号:US20090269305A1
公开(公告)日:2009-10-29
The embodiments provide compounds of the general Formulae I, II, III, IV, V, VI, VII, and X, as well as compositions, including pharmaceutical compositions, comprising a subject compound. The embodiments further provide treatment methods, including methods of treating a hepatitis C virus infection and methods of treating liver fibrosis, the methods generally involving administering to an individual in need thereof an effective amount of a subject compound or composition.
Synthesis of 11-Hydroxyl <i>O</i>-Methylsterigmatocystin and the Role of a Cytochrome P-450 in the Final Step of Aflatoxin Biosynthesis
作者:Daniel W. Udwary、Linda K. Casillas、Craig A. Townsend
DOI:10.1021/ja012185v
日期:2002.5.1
Aspergillus parasiticus in accord with findings in A. flavus. The first oxidative cycle is proposed to result in the formation of 11-hydroxy O-methylsterigmatocystin (HOMST), while the second entails aryl ring cleavage, demethylation, dehydration, decarboxylation, and rearrangement to give aflatoxin - a remarkable sequence of transformations. To test this hypothesis, HOMST has been synthesized by an alkylnitrilium
Thiophilic Lewis acids (e.g. zinc iodide) have a pronounced catalytic effect on the formal [2+2] cycloaddition of alkynyl silyl sulfides 2 and Schiff bases 3 to give 2-azetidinethiones 4. In contrast to uncatalyzed reactions, a large number of functionalities is tolerated and yields are significantly improved.
Novel 7-azido-3-cephem compounds are prepared via .alpha.-amino-phosphonoacetate esters. The cephem compounds are intermediates for the preparation of novel and known useful antibiotic cephalosporins.