关键词： Anions   Peptides and proteins   Genetics   Ketones   Mixtures  

摘要： The BP3 . Et(2)O-promoted Diels-Alder addition of 1-acetylvinyl RADO(Et)-ate (RADO(Et)-ate = 3-ethyl-2-oxo-6,8-dioxa-3-azabicylo[3.2.1]octane-7-exo-carboxylate) to 1-(dimethosymethyl)-2,3,5,6-tetramethylidene-7-oxabicyclo[2.2.1]heptane led to one major monoadduct that added to 1,2-didehydrobenzene and was converted into (-)-4-demethoxy-7-deoxydaunomycinone and (2R)-12-acetoxy-2-acetyl-5-(bromomethyl)-1,2,3,4-tetrahydronaphthacen-2-yl RADO(Et)-ate. The latter compound was used to construct (8R)-8-acetyl-6,8-dihydroxy-11-[[(3'-[(aminopropyl)oxy]-, -4'-[(aminobutyl)oxy], and -5'-[(aminopenty)oxy]methyl]-7,8,9,10-tetrahydronaphthacene-5,12-dione hydrochloride (-)-8, (-)-9, (-)-10, respectively, as well as (8R)-8-acetyl-6,8-dihydroxy-11-[[[2'-[(3 ''-aminopropyl)amino]ethyl]oxy]-((-)-11) and -[[[3'-[(3 ''-aminopropyl)amino]propyl]oxy]methyl]7,8,9,10--tetrahydronaphthacene-5,12-dione hydrochloride ((-)-12). (8R)-8-Acetyl-6,8-dihydroxy-11-[[(alpha-L-diaunosaminyl)oxy]methyl]-7,8,9,10-tetrahydronaphthacene-5,12-dione hydrachloride ((-)-13), a mimic of idarubicin, was also prepared. Absorbance and fluorescence titration experiments showed (-)-8, (-)-9, and (-)-10 to intercalate calf thymus DNA whereas (-)-11, (-)-12, and (-)-13 did not. The best intercalator was (-)-9 (K-b = (1.1 +/- 0.1) x 10(5) M(-1)) with the [(4'-aminobutyl)oxy]-methyl chain. Inhibition of topoisomerase II-induced DNA strand religation wats observed for (-)-8 at a concentration of 50 mu M.

关键词： 药物   手性工业   不对称合成   手性催化  

摘要： 综述了工业上生产手性化合物的化学和生物学方法，以及不对称化学合成和生物合成的新进展及应用前景。

关键词： 地尔硫Zhuo   化学合成   不对称合成  

摘要： 重点介绍了地尔硫的化学合成和拆分方法，以及近年来在其不对称合成领域的进展。

关键词： Redox reactions   Alcohols   Reaction products   Amines   Enantioselective synthesis  

摘要： The asymmetric synthesis of a series of 2-(1-aminoalkyl) piperidines using (-)-2-cyano-6-phenyloxazolopiperidine 1 is described. LiAlH4 reduction of 1 followed by hydrogenolysis led to the diamine 3. The same strategy applied to C-2-methylated compound 7 afforded [(2S)-2-methylpiperidin-2-yl]methanamine (9). Addition of lithium derivatives to the cyano group of 1 resulted in the formation of an intermediate imino bicyclic system (11a-c) which could be diastereoselectively reduced to substituted diamino alcohols 13a-c. The addition of an excess of PhLi to 1 in the presence of LiBr furnished disubstituted amine 19, the precursor of diphenyl[(2S)-piperidin-2-yl]methanamine (22).

关键词： Hydroxyls   Alcohols   Aldehydes   Alkyls   Enantioselective synthesis  

摘要： Presents a study on the asymmetric synthesis of the C8-C25 tris-oxazole fragment in the synthesis of Ulapualide A, an emerging class of secondary marine metabolites. General application to the entire class of natural products; Iterative Hantzsch-oxazole protocol; Disconnection of amide linkage.

关键词： Crystallization   Peptides and proteins   Hydrolysis   Organic compounds   Pharmaceuticals  

摘要： A convergent synthesis of [S-(R*,S*)]-2-[4-[(4-methylpiperazin-1-yl)carbonyl]phenoxy]-3,3-diethyl-N-[1-[3,4-(methylenedioxy)phenyl]butyl]-4-oxo-1-azetidinecarboxamide (L-694,458, 1), a potent human leukocyte elastase inhibitor, was achieved via chiral synthesis of key intermediates: (S)-3,3-diethyl-4-[4'-[(N-methylpiperazin-1-yl)carbonylphenoxy]-2-azetidinone (2) and (R)-alpha-propylpiperonyl isocyanate (3). Synthesis of beta-lactam 2 was achieved by a novel enantioselective lipase hydrolysis of ester 5 to produce (S)-3,3-diethyl-4-(4'-carboxyphenoxy)-2-azetidinone (6) (60% yield, three cycles, 93% ee) with isolation, epimerization, and recycling of the undesired (R)-ester 5. Isocyanate 3 was prepared by chiral addition of Zn(n-Pr)(2) to piperonal (98% yield, 99.2% ee), azide displacement and reduction to (R)-alpha-propylpiperonylamine (11) (58% yield, 85% ee), crystallization as the D-pyroglutamic acid salt (92% yield, 98.2% ee), and isocyanate formation (98% yield) with phosgene.

关键词： Alcohols   Anions   Column chromatography   Aldehydes   Allylation  

摘要： Zn-mediated allylation and propargylation of (R)-2,3-O-cyclohexylideneglyceraldehyde (1) in aqueous medium following Luche's procedure afforded the anti homoallylic 3 and homopropargylic 8 alcohols in good yield and with high stereoselectivity, Crotylation of 1 under similar conditions afforded appreciable amounts of erythro-5 and threo-6 alcohols. In each case, the diastereo alcohols are separable by column chromatography. Compound 8 on appropriate chemical manipulation of its functionalities gave the (S)-enantiomer of (R)-13, a useful synthon of LTB(4). Compound 3 on chemical elaboration afforded a diversely functionalized triol derivative 15, a potentially useful synthon for many bioactive compounds.

关键词： Protective groups   Organophosphorus compounds   Organic synthesis   Aldehydes   Chemical synthesis  

摘要： We report our synthesis of the C-1-C-25 fragment of serine/threonine phosphatase PP1 and PP2A inhibitor, calyculin C. Synthetic efforts were directed initially toward the synthesis of a spiroketal core fragment (7), which culminated in completion of the bottom half of the natural product. The synthesis of fragment 7 and subsequent elaboration relied on an allylboration strategy for introduction of chirality. The C-1-C-8 fragment representing the potentially unstable tetraene moiety was introduced as a separate entity.

关键词： Salts   Coupling reactions   Amides   Organic compounds   Cations  

摘要： We report our synthesis of the C-26-C-37 fragment of serine/threonine protein phosphatase PP1 and PP2A inhibitor calyculin C (1). Outlined in this paper are synthetic approaches to the two components based on disconnection at the C-33-N-3 amide bond. We report the successful synthesis of the C-33-C-37 aza-sugar derived from D-lyxose which was coupled onto a C-26-C-32 aminooxazole originating from L-pyroglutamic acid. Elaboration of the resulting amide to a fully deprotected C-26-C-37 fragment of calyculin C completed our synthesis. This provided an appropriate phosphonium salt for use in a Wittig olefination for joining both halves of the natural product.

关键词： ALLYLIC ALCOHOLS   SCH-42427 SM-9164   EPOXIDATION  

摘要： SM-9164, a biologically active enantiomer of antifungal agent SM-8668, was prepared by asymmetric synthesis in 10 steps in 13% overall yield from commercially available 2-chloro-1-(2,4-difluorophenyl)ethanone. The crucial steps were Katsuki-Sharpless asymmetric epoxidation of the (E)-allylic alcohol and epimerization of the erythro-sulfone to the desired threo-isomer under basic conditions.