Asymmetric synthesis of taxol arid taxotère side chains by enolate hydroxylation

1996 ◽  
Vol 74 (4) ◽  
pp. 621-624 ◽  
Author(s):  
Stephen Hanessian ◽  
Jean-Yves Sancéau
Keyword(s):  
Asymmetric Synthesis ◽  
Key Words ◽  
Side Chains ◽  
Key Words Taxol ◽  
Phosphoric Triamide ◽  
Enolate Hydroxylation

We report an asymmetric synthesis of the taxol and taxotère side chains by hydroxylation of enolates derived from N-substitued methyl 3-amino-3-phenyl propionate with the oxodiperoxymolybdenum (pyridine) (hexamethyl phosphoric triamide) complex (MoOPH). Key words: taxol and taxotère side chains, hydroxylation.

ChemInform Abstract: Asymmetric Synthesis of Taxol and Taxotere Side Chains by Enolate Hydroxylation

ChemInform ◽  
2010 ◽  
Vol 27 (39) ◽  
pp. no-no
Author(s):  
S. HANESSIAN ◽  
J.-Y. SANCEAU
Keyword(s):  
Asymmetric Synthesis ◽  
Side Chains ◽  
Enolate Hydroxylation

Diastereoselective Synthesis of (3R,5R)-γ-Hydroxypiperazic Acid

Synlett ◽  
2021 ◽  
Author(s):  
Juan R. Del Valle ◽  
Taylor A. Gerrein ◽  
Yassin M. Elbatrawi
Keyword(s):  
Asymmetric Synthesis ◽  
Late Stage ◽  
Ring Formation ◽  
Peptide Chain ◽  
Nonribosomal Peptides ◽  
Diastereoselective Synthesis ◽  
Hydroxylation Reaction ◽  
Enolate Hydroxylation

AbstractWe report an asymmetric synthesis of the (3R,5R)-γ-hydroxypiperazic acid (γ-OHPiz) residue encountered in several bioactive nonribosomal peptides. Our strategy relies on a diastereoselective enolate hydroxylation reaction and electrophilic N-amination to provide the acyclic γ-OHPiz precursor. This orthogonally protected α-hydrazino acid intermediate is amenable to late-stage diazinane ring formation following incorporation into a peptide chain. We determined the N-terminal amide rotamer propensity of the γ-OHPiz residue and showed that the γ-OH substituent enhances trans-amide bias relative to piperazic acid.

Colicinogeny of O157:H7 enterohemorrhagic Escherichia coli and the shielding of colicin and phage receptors by their O-antigenic side chains

1991 ◽  
Vol 37 (2) ◽  
pp. 97-104 ◽  
Author(s):  
D. E. Bradley ◽  
S. P. Howard ◽  
H. Lior
Keyword(s):  
Escherichia Coli ◽  
Molecular Weight ◽  
Hemolytic Uremic Syndrome ◽  
Key Words ◽  
Bloody Diarrhea ◽  
Enterohemorrhagic Escherichia Coli ◽  
Side Chains ◽  
Uremic Syndrome ◽  
O Antigens ◽  
Clinical Conditions

Twenty O157:H7 enterohemorrhagic Escherichia coli strains from patients with different clinical conditions were tested for colicinogeny and the presence of Verotoxin (VT) genes. From bloody diarrhea cases, 7/8 isolates and from hemolytic uremic syndrome cases 3/5 isolates all synthesized what appeared to be colicin D. The remaining strains, which included 7 from asymptomatic sources, were noncolicinogenic. The plasmid determining the colicin was found to be 1.4 kb larger than the 5.2-kb pColD. The colicin D protein had a molecular weight of about 90 000, whereas the O157 colicin was 87 000. The plasmid was designated pColD157 to reflect these differences. Of O157:H7 isolates 17/20 had genes for both of the Verotoxins VT1 and VT2, and the remaining 3/20 for VT1 only. There was no correlation between the presence of VT determinants and colicinogeny or symptoms. The O157:H7 strains exhibited significant resistance to other colicins and bacteriophages. Key words: O-antigens, enterohemorrhagic, colicin, Verotoxin, bacteriophages.

Colicins G and H and their host strains

1991 ◽  
Vol 37 (10) ◽  
pp. 751-757 ◽  
Author(s):  
D. E. Bradley
Keyword(s):  
Escherichia Coli ◽  
Key Words ◽  
Side Chains ◽  
Human Origin ◽  
Wild Type ◽  
E Coli ◽  
Molecular Weights ◽  
Protein Receptors ◽  
Type Strains ◽  
Host Strains

Escherichia coli strains CA46(pColG) and CA58(pColH) each apparently synthesized two generally similar bactericidal colicin proteins whose molecular weights were approximately 5 500 and 100 000. These proteins were more resistant to trypsin than representative colicins A, D, E1, and V. The smooth wild-type strains harbouring plasmids pColG and pColH were serotyped O169:NM and O30:NM, respectively, being typically associated with nonpathogenic E. coli of human origin. Rough and semirough variants, which were selected using resistance to novobiocin, were intrinsically insensitive to almost as many colicins (10 tested) as their parents. For this reason the wild-type strains would not be useful for identifying colicins G and H on the basis of immunity. The O antigenic side chains of both wild-type strains shielded three of the six bacteriophage protein receptors tested. Key words: colicin, protein, plasmid, O antigen, bacteriophage.

ChemInform Abstract: Asymmetric Synthesis of the Taxol and Taxotere C-13 Side Chains.

ChemInform ◽  
2010 ◽  
Vol 26 (8) ◽  
pp. no-no
Author(s):  
M. E. BUNNAGE ◽  
S. G. DAVIES ◽  
C. J. GOODWIN
Keyword(s):  
Asymmetric Synthesis ◽  
Side Chains

Transition metal mediated asymmetric synthesis VIII. Preparation of tricarbonyl(cyclohexadienyl)iron(1 +) cations with oxygenated side-chains

1988 ◽  
Vol 353 (3) ◽  
pp. C47-C50 ◽  
Author(s):  
Gary P. Randall ◽  
G.Richard Stephenson ◽  
Ewan J.T. Chrystal
Keyword(s):  
Transition Metal ◽  
Asymmetric Synthesis ◽  
Side Chains

Asymmetric Synthesis of Helically Stable Poly(quinoxaline-2,3-diyl)s Having Hydrophilic and/or Hydrophobic Side Chains

1998 ◽  
Vol 31 (5) ◽  
pp. 1697-1699 ◽  
Author(s):  
Yoshihiko Ito ◽  
Toshiyuki Miyake ◽  
Takafumi Ohara ◽  
Michinori Suginome
Keyword(s):  
Asymmetric Synthesis ◽  
Side Chains

scholarly journals 2-Phenyl-tetrahydropyrimidine-4(1H)-ones – cyclic benzaldehyde aminals as precursors for functionalised β2-amino acids

2009 ◽  
Vol 5 ◽  
Author(s):  
Markus Nahrwold ◽  
Arvydas Stončius ◽  
Anna Penner ◽  
Beate Neumann ◽  
Hans-Georg Stammler ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Asymmetric Synthesis ◽  
Side Chains ◽  
Acid Labile

Novel procedures have been developed to condense benzaldehyde effectively with β-amino acid amides to cyclic benzyl aminals. Double carbamate protection of the heterocycle resulted in fully protected chiral β-alanine derivatives. These serve as universal precursors for the asymmetric synthesis of functionalised β2-amino acids containing acid-labile protected side chains. Diastereoselective alkylation of the tetrahydropyrimidinone is followed by a chemoselective two step degradation of the heterocycle to release the free β2-amino acid. In the course of this study, an L-asparagine derivative was condensed with benzaldehyde and subsequently converted to orthogonally protected (R)-β2-homoaspartate.

Previously published / Prédémment paruAsymmetric total synthesis of (+)-exo-brevicomin based on enantioconvergent biocatalytic hydrolysis of an alkene-functionalized 2,3-disubstituted epoxide

2002 ◽  
Vol 80 (6) ◽  
Author(s):  
Sandra F Mayer ◽  
Harald Mang ◽  
Andreas Steinreiber ◽  
Robert Saf ◽  
Kurt Faber
Keyword(s):  
Total Synthesis ◽  
Asymmetric Synthesis ◽  
Bark Beetle ◽  
Epoxide Hydrolase ◽  
Side Chains ◽  
Beetle Species ◽  
Epoxide Hydrolases ◽  
Pheromone System ◽  
Enantioconvergent Hydrolysis ◽  
Hydrolysis Of

A short total asymmetric synthesis of (+)-exo- and (–)-endo-brevicomin ((+)-exo-3 and (–)-endo-3), which are components of the attracting pheromone system of several bark-beetle species belonging to the genera Dendroctonus and Dryocoetes, was accomplished via a chemoenzymatic protocol. The key step consisted of biocatalytic hydrolysis by bacterial epoxide hydrolases of cis-configured 2,3-disubstituted oxiranes bearing olefinic side chains. This reaction proceeded in an enantioconvergent fashion, by affording a single enantiomeric vic-diol from the rac-epoxide in up to 92% ee and 83% isolated yield.Key words: bacterial epoxide hydrolase, 2,3-disubstituted oxirane, enantioconvergent hydrolysis, (+)-exo-brevicomin, (–)-endo-brevicomin.

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