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Archive for December, 2010

Synthesis of Variecolortide

Posted by naturalproductman on December 31, 2010

Variecolortides have been synthesized and reported by Trauner and co-workers.

hetero Diels Alder

ACIEE paper

Posted in Cycloaddition, Diels-Alder, Methodology, Named Reactions, Pericyclic reactions, Polyketides | Leave a Comment »

Phenoxonium Ions

Posted by naturalproductman on December 31, 2010

Thomas Pettus and co-worker at UCSB have published in JACS on a lead(IV) acetate mediated (5+2) oxidative dearomatization to access some cedranoid sesquiterpenes.

oxidative

 

JACS paper

Posted in Cascade Reactions, Methodology, Ring forming, Sesquiterpenes, Spirocyclic centers | Leave a Comment »

Ningalin Synthesis

Posted by naturalproductman on December 29, 2010

Yanxing Jia and co-workers have published in Organic Letters on the synthesis of ningalin.

silver

 

OL paper

Posted in Alkaloids, Cascade Reactions, Methodology, Silver, Transition Metal | Leave a Comment »

Fischambiguines

Posted by naturalproductman on December 27, 2010

Jimmy Orjala and co-workers at the University of Illinois in Chicago have published in Phytochemistry on the isolation of some antibacterial compounds – fishambiguine B had an MIC value of 2 micromolar against Mycobacterium tuberculosis.

anti-microbial agents

Phytochemistry paper

Posted in Alkaloids, Antibiotics | Leave a Comment »

1,3-Dipolar Cycloaddition Followed by Decarboxylation

Posted by naturalproductman on December 26, 2010

John Ryan and co-workers at the University of Melbourne have published in Organic Letters on a reaction which involves the 1,3-dipolar cycloaddition between an anhydride and a non-stabilized ylide followed by decarboxylation.

1,3-dipolar cycloaddition

 

OL paper

Posted in Cascade Reactions, Cycloaddition, Methodology, Pericyclic reactions, Ylides | Leave a Comment »

A Slick Way to Make Allenes

Posted by naturalproductman on December 25, 2010

Jianbo Wang and co-workers at the Peking University have published in ACIEE on a nice way to make allenes – a coupling between a terminal alkyne and an N-tosylhydrazone.

allene

ACIEE paper

Posted in Allenes, Carbene, Cascade Reactions, Copper, Methodology, Transition Metal | Leave a Comment »

Pleurocybellaziridine

Posted by naturalproductman on December 25, 2010

First things first:  Merry Christmas!  Happy holidays!

Toshiyuki Kan and co-workers from the University of Shizuoka have published in ACIEE on the evidence of an aziridine containing amino acid in a fungus called Angel’s wing.  They did some detective work because the aziridine containing amino acid dubbed pleurocybellaziridine is not stable enough for observation.  The carboxylic acid was not stable so they derivitized the natural product to the methyl ester form, which was more stable.  They also synthesized the aziridine containing amino acid to confirm the structures through spectral data.  The aziridine was synthesized via Mitsunobu conditions.  Interestingly the carboxylic acid form is more cytotoxic (87 micromolar, strong activity) compared to the methyl ester (233 micromolar, weak activity).  Pleurocybellaziridine damages the oligodendrocytes, which makes up the myelin sheath in the brain.

angel's wing

ACIEE paper

Posted in Amino Acids, Methodology, Mitsunobu, Named Reactions | Leave a Comment »

Unexpected Epoxidation

Posted by naturalproductman on December 23, 2010

Danishefsky and co-workers have published in JACS on an epoxidation of a substrate with an olefin tethered by a sulfoxide.

pummerer

 

JACS paper

Posted in Cascade Reactions, Mechanistic, Methodology, Named Reactions, Pummerer rearrangement | Leave a Comment »

Neocarzinostatin

Posted by naturalproductman on December 23, 2010

Der-Hang Chin and co-workers at National Chung Hsing University in Taiwan have published in Chemistry a European Journal on a neat carrier protein that cyclizes neocarzinostatin, an enediyne.

enediyne

 

Chemistry a European Journal paper

Posted in Chemical Biology, Enediynes, Proteins | Leave a Comment »

Boekelheide Rearrangement Strategy to form Rings Intramolecularly

Posted by naturalproductman on December 23, 2010

Daniele Andreotti and co-workers at GlaxoSmithKline in Italy have published in the European Journal of Organic Chemistry on a Boekelheide rearrangement to form nitrogen heterocycles from pyridine-N-oxides.

rearrangement

 

European JOC paper

Posted in Cascade Reactions, Methodology, Named Reactions, Ring forming | Leave a Comment »

 
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