Advertisement

Topics

A flexible asymmetric approach to methyl 5-alkyltetramates and its application in the synthesis of cytotoxic marine natural product belamide a.

Summary of "A flexible asymmetric approach to methyl 5-alkyltetramates and its application in the synthesis of cytotoxic marine natural product belamide a."

By using a methyl tetramate derivative (R)- or (S)-9 as a novel chiral building block, a direct, flexible, and highly enantioselective approach to methyl (R)- or (S)-5-alkyltetramates (2) is disclosed. Among the synthesized methyl 5-alkyltetramates 2, methyl 5-methyltetramate (2 a) is found in cytotoxic mirabimide E (4) and dysideapyrrolidone (5), and methyl 5-benzyltetramate (2 g) is a substructure in the potent antineoplastic dolastatin 15 (3). On the basis of this method, the first asymmetric synthesis of the antimitotic tetrapeptide belamide A (7) has been achieved in seven steps from (S)-9, with an overall yield of 23.8 %. Not only have the structure and absolute configuration of (+)-belamide A (7) been confirmed, but also the solvent used for recording the (13) C NMR spectrum, the (13) C NMR spectrum data correlation, and optical rotation data of natural belamide A (7) have been revised.

Affiliation

Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, Fujian 361005 (P.R. China), Fax: (+86) 592-2186400.

Journal Details

This article was published in the following journal.

Name: Chemistry (Weinheim an der Bergstrasse, Germany)
ISSN: 1521-3765
Pages: 958-68

Links

DeepDyve research library

PubMed Articles [22164 Associated PubMed Articles listed on BioPortfolio]

Asymmetric Synthesis of (+)-anti- and (-)-syn-Mefloquine Hydrochloride.

The asymmetric (er > 99:1) total synthesis of (+)-anti- and (-)-syn-mefloquine hydrochloride from a common intermediate is described. The Sharpless asymmetric dihydroxylation is the key asymmetric tra...

The first asymmetric synthesis of marliolide from readily accessible carbohydrate as chiral template.

A simple and efficient strategy for the first asymmetric total synthesis of marliolide was accomplished by using stereoselective alkylation of the dianion of the β-hydroxy lactone enolate with myrist...

Catalytic SN 2'- and Enantioselective Allylic Substitution with a Diborylmethane Reagent and Application in Synthesis.

A catalytic method for the site- and enantioselective addition of commercially available di-B(pin)-methane to allylic phosphates is introduced (pin=pinacolato). Transformations may be facilitated by a...

Multicomonent Strategy for the Synthesis of Prostaglandin E2 Methyl Ester under Anion Relay Chelation Control.

Starting from four components, the enantioselective synthesis of prostaglandin E2 methyl ester has been achieved through a highly stereoselective heteroatom-directed conjugate addition (HADCA) reactio...

Catalytic Asymmetric Addition of Both Alkyl and Aryl Alkynes to N-(Diphenylphosphinoyl)imines.

A 3,3'-di(1-diphenylmethylpiperazinyl)methyl H8BINOL compound (S)-11 was prepared from the Mannich-type reaction of (S)-H8BINOL with paraformaldehyde and 1-(diphenyl)methyl piperazine. This compound c...

Clinical Trials [3141 Associated Clinical Trials listed on BioPortfolio]

Rigid Versus Flexible Cystoscopy in Women

The study will help define the best tolerated approach to cystoscopy in women by randomly comparing flexible to rigid cystoscopy. Previous randomized studies evaluated rigid cystoscopy und...

Efficacy of Topical Calcipotriol-assisted AFL-PDT in Actinic Keratosis

Vitamin D(Vit D) is a pro-differentiation agent that enhances the accumulation of protoporphyrin IX (PpIX) after MAL(methyl-aminolevulinate) incubation in actinic keratosis and may have si...

Flexible vs Rigid Cytoscopy in Women

This study will help define the best tolerated approach to cystoscopy by randomly comparing the flexible to the rigid cystoscope.

Corneal Cross-linking and Refractive Surface Ablation in Patients With Asymmetric Corneas

The purpose of this study is to evaluate safety and efficacy of corneal cross-linking and photorefractive keratectomy for refractive correction in patients with bilateral asymmetric topogr...

Evaluation of Topic Anaesthesia for Laryngoscopy With Fibroscopy During Paediatric Ear Nose Throat (ENT)Consultation

The purpose of this work is to estimate the efficiency in terms of pain of the application of a local anesthetic (xylocaïne viscous 2%®) during the realization of an examination in naso-...

Medical and Biotech [MESH] Definitions

A cytotoxic polypeptide quinoxaline antibiotic isolated from Streptomyces echinatus that binds to DNA and inhibits RNA synthesis.

(1 beta,2 alpha,11 beta,12 alpha,15 beta(S))-11,20-Epoxy-1,2,11,12-tetrahydroxy-15-(2-hydroxy-2-methyl-1-oxobutoxy)picras-3-en-16-one. A quassinoid (Simaroubolide) from Simaruba glauca, a tropical shrub. It has been used as an antiamebic agent and is found to be cytotoxic. It may be of use in cancer chemotherapy.

Any situation where an animal or human is trained to respond differentially to two stimuli (e.g., approach and avoidance) under reward and punishment conditions and subsequently trained under reversed reward values (i.e., the approach which was previously rewarded is punished and vice versa).

A cytokine which resembles IL-1 structurally and IL-12 functionally. It enhances the cytotoxic activity of NK CELLS and CYTOTOXIC T-LYMPHOCYTES, and appears to play a role both as neuroimmunomodulator and in the induction of mucosal immunity.

Brief therapeutic approach which is ameliorative rather than curative of acute psychiatric emergencies. Used in contexts such as emergency rooms of psychiatric or general hospitals, or in the home or place of crisis occurrence, this treatment approach focuses on interpersonal and intrapsychic factors and environmental modification. (APA Thesaurus of Psychological Index Terms, 7th ed)

Quick Search
Advertisement
 


DeepDyve research library

Searches Linking to this Article