Total Synthesis of the Chlorinated Marine Natural Product Dysamide B
摘要:
[GRAPHICS]Two approaches to the synthesis of (2S,4S)-5,5-dichloroleucine are compared, and the parent amino acid was used in the first total synthesis of the polychlorinated marine natural product, dysamide B. A key step was the lead tetraacetate-mediated decarboxylation of an alpha, alpha-dichloro acid in the presence of 1,4-cyclohexadiene to generate the dichloromethyl group.
A Practical Total Synthesis of Hapalosin, a 12-Membered Cyclic Depsipeptide with Multidrug Resistance-Reversing Activity, by Employing Improved Segment Coupling and Macrolactonization
作者:Claudio Palomo、Mikel Oiarbide、Jesús M. García、Alberto González、Raquel Pazos、José M. Odriozola、Patricia Bañuelos、Mónica Tello、Anthony Linden
DOI:10.1021/jo0497499
日期:2004.6.1
A practical total synthesis of hapalosin, a compound with multidrug resistance-reversing activity, has been carried out using an unprecedented macrolactonization strategy. One of the features of the new approach is the straightforward and fully stereocontrolled access to the key γ-amino β-hydroxy carboxylic acid subunit via an efficient acetate aldol addition reaction with N-methyl α-aminoaldehydes
Peptide derivatives provided by the present invention are compounds of the general formula ##STR1## wherein R.sup.1 represents a hydrogen atom or the methyl or hydroxymethyl group or a mono-, di- or trihalomethyl mgroup; R.sup.2 represents the characterizing group of an .alpha.-amino acid of the type normally found in proteins or a lower alkyl or hydroxy- (lower alkyl) group other than the characterising group of an .alpha.-amino acid of the type normally found in proteins; R.sup.3 represents a lower alkyl, lower cycloalkyl, lower alkenyl, aryl or aryl-(lower alkyl) group; R.sup.4 represents a hydrogen atom or a lower alkyl group; n stands for 1,2 or 3; the configuration at the carbon atom designated as (a) is (R) when R.sup.1 represents other than a hydrogen atom and the configuration at the carbon atom designated as (b) is (L) when R.sup.2 represents other than a hydrogen atom, and pharmaceutically acceptable salts thereof. The compounds exhibit activity as antibacterial agents against a range of gram-positive and gram-negative bacteria. Also disclosed are intermediates and a process for the production of the end product.
Phosphorhaltige Peptidderivate, deren Herstellung, Zwischenprodukte bei deren Herstellung und diese enthaltende pharmazeutische Präparate
申请人:F. HOFFMANN-LA ROCHE & CO.
Aktiengesellschaft
公开号:EP0002822A1
公开(公告)日:1979-07-11
Neue antibakteriell aktive Verbindung der Formel
worin R' Wasserstoff, Methyl, Hydroxymethyl, Mono-, Di-oder Trihalogenmethyl; R2 eine für a-Aminosäuren, wie sie normalerweise in Proteinen vorkommen, charakteristische Gruppe, oder eine von den Niederalkyl- bzw. Hydroxyniederalkylgruppen, wie sie für normalerweise in Proteinen vorkommende a-Aminosäuren charakteristisch sind, sich unterscheidende Niederalkyl- bzw. Hydroxyniederalkylgruppe; R3 Niederalkyl, Niedercycloalkyl, Niederalkenyl, Aryl- oder Arylniederalkyl und R' Wasserstoff oder Niederalkyl bedeutet; n für 1, 2 oder 3 steht; mit R-Konfiguration am mit (a) bezeichneten C-Atom (falls R1 = H) und L-Konfiguration am mit (b) bezeichneten C-Atom (falls R2 = H);
sowie pharmazeutisch verträgliche Salze solcher Verbindungen, deren Herstellung nach an sich bekannten Methoden der Peptidchemie und pharmazeutische Präparate, enthaltend solche Peptidderivate.
Novel Formation and Crystal Structure of 2-(2,2,2-Trifluoroethylidene)-6-trifluoro-methyl-2,3-dihydro-4H-1,4-oxazin-3-ones from N-Acetyl-N-alkyl-a-amino Acids
The title compounds (2a-g) were formed from N-acetyl-N-alkyl-alpha-amino acids (la-g) on treatment with trifluoroacetic anhydride in the presence of pyridine. The structure of the product (2a) was determined by single crystal X-Ray analysis.