Track topics on Twitter Track topics that are important to you
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.
This article was published in the following journal.
Name: Chemistry (Weinheim an der Bergstrasse, Germany)
A short and flexible asymmetric synthesis of ramariolides A and C was accomplished. A bimetallic catalytic system consisting of Pd-Cu-mediated cascade cyclization, unprecedented Z-E isomerization by a...
A catalytic asymmetric method for the synthesis of chiral isoquinolinonaphthyridines has been developed. A chiral disulfonimide catalyzes a redox cyclization reaction between 2-methyl-3-aldehydeazaare...
An I2-promoted domino bicyclization approach via multiple sequential C-H functionalization was serendipitously discovered for the synthesis of 1,2-fused oxindoles from methyl ketones and anilines. Thi...
Asymmetric catalysis for chiral compound synthesis is a rapidly growing field in modern organic chemistry. Asymmetric catalytic processes have been indispensable for the synthesis of enantioselective ...
The first asymmetric synthesis of important alfa,alfa-disubstituted N-alkyl allyl amine scaffolds via allylic substitution is reported. This approach is based on palladium catalysis and features ample...
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...
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...
This study will help define the best tolerated approach to cystoscopy by randomly comparing the flexible to the rigid cystoscope.
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...
This study will assess changes in visual acuity and corneal symmetry after corneal collagen cross-linking (CXL) of asymmetric corneas.
A cytotoxic polypeptide quinoxaline antibiotic isolated from Streptomyces echinatus that binds to DNA and inhibits RNA synthesis.
Method of treating pain associated with the sphenopalatine ganglion located in the PTERYGOPALATINE FOSSA, posterior to the middle nasal turbinate. The transnasal approach involves application of suitable local anesthetic to the mucous membrane overlying the ganglion.
(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.
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.
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).