An application of the palladium-catalyzed, allylic amination of unsaturated sugars: a new synthesis of d-forosamine

Baer, Hans H.; Hanna, Zaher S.

doi:10.1016/s0008-6215(00)85594-9

Cited by 18 publications

(1 citation statement)

References 23 publications

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“…Compound 5 was recrystallized with hexane/acetone to give a colorless platelet . X-ray crystallography for 5 elucidated the aminosugar (B) as 2,3,4,6-tetradeoxy-4-methylamino-β- d - erythro -hexopyranose ( N -monodemethyl- d -forosamine, Figure S14) . Thus, incednine ( 1 ) consists of a novel skeletal structure, enol-ether amide in the 24-membered macrolactam core, with two aminosugars.…”

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Discovery of Incednine as a Potent Modulator of the Anti-apoptotic Function of Bcl-xL from Microbial Origin

et al. 2008

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Anti-apoptotic oncoproteins Bcl-2 and Bcl-xL are overexpressed in many cancers, 1 resulting in the expansion of a transformed population and the advancement of the multidrug-resistant stage. Consequently, Bcl-2/Bcl-xL have stood out among molecular targets in oncology, and the functional blockade of these proteins will be an aid to novel anti-tumor therapies. Since these proteins are known to show an anti-apoptotic effect partly through forming a heterodimer with pro-apoptotic Bcl-2 members, such as Bax and Bak, 2 several researchers have rationally designed and synthesized compounds that target their binding pocket and have reported several compounds such as HA14-1 and ABT-737 as Bcl-2/BclxL inhibitors. 3 Currently, several lines of evidence indicate that Bcl-2/Bcl-xL clearly have other functions related to their abilities to interact physically with many other proteins; however, the underlying mechanisms for the regulation of apoptosis by Bcl-2/ Bcl-xL through interacting with such proteins still remain unclear. 4 For further understanding of the regulation of apoptosis by Bcl-2/ Bcl-xL, the development of a new class of chemical tools is required. Cell-based chemical-genetic screens have been used to help discover small, cell-permeable bioactive molecules that induce phenotypic changes, and through subsequent identification of their target proteins, they can contribute to reveal the molecular basis of biological processes. Therefore, we constructed a cell-based chemical-genetic screening system to discover small molecules that induce apoptosis in Bcl-xL-overexpressing human small cell lung carcinoma Ms-1 cells when combined with anti-tumor drugs. In the course of our screening, we isolated a structurally and functionally unique compound, named incednine (1), from the culture broth of Streptomyces sp. ML694-90F3. Here, we describe the isolation, structure elucidation, and biological activities of 1.Incednine (1) was obtained (18.9 mg/L) as a pale-yellow powder from the cultured broth of the producing strain by centrifugal liquid-liquid partition chromatography for two reasons: (1) this compound decomposes easily under acidic conditions or when exposed to light, and (2) the isolation using a solid carrier such as silica gel was inefficient. The molecular formula of 1 was found to be C 42 H 63 N 3 O 8 by HRESIMS. The characteristic UV absorption (λ max ) 294.5, 309.5, 322.5, 356.0 nm) was indicative a polyene moiety. The positive color reaction to GL reagent, negative reaction to ninhydrin, and the typical IR absorption at 1650, 1510 cm -1 suggested the presence of an amido group.The assignable NMR spectra were obtained when the sample was dissolved in CD 3 OH/H 2 O (3:1) and measured at -5°C. The 13 C NMR and DEPT spectra revealed that 1 contained 42 carbons, including one carbonyl, four quaternary sp 2 , one quaternary sp 3 , fourteen sp 2 methines, nine sp 3 methines, four methylenes, and nine methyl carbons. One carbonyl signal and eighteen sp 2 carbons require the presence of three rings from the unsaturatio...

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Discovery of Incednine as a Potent Modulator of the Anti-apoptotic Function of Bcl-xL from Microbial Origin

et al. 2008

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Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents

2002

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Reductive amination is an important tool for synthetic organic chemists in the construction of carbon‐nitrogen bonds. This reaction, also termed reductive alkylation, involves condensation of an aldehyde or ketone with an amine in the presence of a reducing agent. A wide variety of substrates can be used including aliphatic and aromatic aldehydes and ketones, and even benzophenones. A range of amines from ammonia to aromatic amines, including those with electron‐withdrawing substituents, can be employed. For particularly sluggish reactions, such as those involving weakly electrophilic carbonyl groups, poorly nucleophilic amines, or sterically congested reactive centers, additives such as molecular sieves or Lewis acids are often useful. This chapter focuses on those conditions in which the carbonyl component, amine, and reducing reagent react in the same vessel. This review is restricted to reductive aminations using borohydride and borane reducing agents. This chapter concentrates on reductive amination chemistry mediated by borohydride and other boron‐containing reducing agents from 1971, the year when sodium cyanoborohydride was introduced, through the middle of 1999. In addition to reductive aminations of aldehyde and ketone substrates, reactions of related structures including acetals, aminals, ketals, carboxylic acids, nitriles, and dicarbonyls that form a nitrogen‐containing ring are reviewed. Intramolecular processes in which the substrate contains both the carbonyl and amine moieties are described. The intramolecular variant is a useful method for preparing cyclic amines. All of the various boron‐containing hydride sources in reductive aminations, including labeled metal hydrides, are reviewed. Instances of reductive aminations that failed are described. Applications of this method to a solid support in parallel synthesis in combinatorial chemistry as well as reductive aminations that proceed in tandem with a second reaction such as reductive lactamizations are discussed.

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Catalytic Asymmetric Synthesis of All Possible Stereoisomers of 2,3,4,6‐Tetradeoxy‐4‐Aminohexopyranosides

et al. 2018

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We recently developed a divergent strategy for the synthesis of all eight possible 2,3,6trideoxyhexopyranosides with three stereogenic centers. However, the diastereoselectivity for one of the three stereogenic centers was low and it was not controlled by catalysts. In this update, we described a systematic method for the first catalytic asymmetric synthesis of all eight possible 2,3,6trideoxyhexopyranosides and all eight possible 2,3,4,6-tetradeoxy-4-aminohexopyranosides.The products derived from this strategy include the glycone of natural products grecocycline A, spinosyn A, and ossamycin. All three stereogenic centers in each product was controlled by a pair of chiral catalysts. The key to the success is the application of our recently developed dynamic kinetic stereodivergent acylation of Achmatowicz rearrangement products and chiral catalyst-directed reduction. Simple dimethylation of the 2,3,4,6-tetradeoxy-4amino sugars afforded derivatives of naturally occurring b-D-forosaminide and b-L-ossaminide.

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An application of the palladium-catalyzed, allylic amination of unsaturated sugars: a new synthesis of d-forosamine

Cited by 18 publications

References 23 publications

Discovery of Incednine as a Potent Modulator of the Anti-apoptotic Function of Bcl-xL from Microbial Origin

Discovery of Incednine as a Potent Modulator of the Anti-apoptotic Function of Bcl-xL from Microbial Origin

Reductive Aminations of Carbonyl Compounds with Borohydride and Borane Reducing Agents

Catalytic Asymmetric Synthesis of All Possible Stereoisomers of 2,3,4,6‐Tetradeoxy‐4‐Aminohexopyranosides

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