Ulleungamides A and B, Modified α,β-Dehydropipecolic Acid Containing Cyclic Depsipeptides from Streptomyces sp. KCB13F003
摘要:
Two novel cyclic depsipeptides, ulleungamides A (1) and B (2), were isolated from cultures of terrestrial Streptomyces sp. Their structures were determined by analyses of spectroscopic data and various chemical transformations, including modified Mosher's method, advanced Marfey's method, PGMF,, GITC derivatizations, and Snatzke's method. Ulleungamides were determined to be a new class of peptides bearing unprecedented units, such as 5-hydroxy-6-methyl-2,3-dehydropipecolic acid, 4,5-dihydroxy-6-methyl-2,3-dehydropipecolic acid, and amino-linked 2-isopropylsuccinic acid. Ulleungamide A displayed growth inhibitory activity against Staphylococcus aureus and Salmonella typhimurium without cytotoxicity.
Compounds according to formula (I), methods of using said compounds singly or in combination with additional agents and compositions of said compounds for the treatment of cancer are disclosed.
Use of hydrolases for the synthesis of cyclic amino acids
作者:Richard C Lloyd、Michael C Lloyd、Mark E.B Smith、Karen E Holt、Jonathan P Swift、Philip A Keene、Stephen J.C Taylor、Raymond McCague
DOI:10.1016/j.tet.2003.10.116
日期:2004.1
The synthesis of several cyclic amino acids that have all the necessary structural features to make them ideal scaffolds for use in medicinal chemistry is described. A key step in each synthesis is the use of hydrolase enzymes to define a chiral centre. In order to elaborate these building blocks into more complex molecules, crystallization and asymmetric hydrogenation were used to define further stereocentres
<i>trans</i>-6-Aminocyclohept-3-enols, a New Designed Polyfunctionalized Chiral Building Block for the Asymmetric Synthesis of 2-Substituted-4-hydroxypiperidines
trans-6-Aminocyclohept-3-enols 18 and ent-18 are new designed polyfunctionalized chiral building blocks for piperidine alkaloids synthesis and are prepared in high yields from the enzymatically derived cyclohept-3-ene-1,6-diol monoacetate (-)-8. Efficient highly enantioselective syntheses of cis-4-hydroxypipecolic acid (1) and piperidines 3 and 4, in both enantiomeric forms, are described. [reaction:
6-Bromomethyl-4<i>H</i>-1,3-dioxin: A Versatile Bromomethyl Vinyl Ketone Equivalent for Heterocycle and Carbocycle Construction
作者:Thomas J. Greshock、Raymond L. Funk
DOI:10.1021/ja0123554
日期:2002.2.1
heated to effect facile retrocycloaddition reactions. The resulting enones smoothly participated in novel endo-conjugate addition reactions with both carbon and nitrogen nucleophiles. For example, several bicyclo[4.3.1]decan-3,10-diones, the carbon framework of the CP compounds, were constructed using this novel annulation strategy. In another natural product study, a benzazocine related to the heterocyclic
Asymmetric Synthesis of the Four Stereoisomers of 4-Hydroxypipecolic Acid
作者:Franklin A. Davis、Tianan Fang、Bin Chao、David M. Burns
DOI:10.1055/s-2000-8710
日期:——
The asymmetric synthesis of all four stereoisomers of 4-hydroxypipecolic acid (1) from the polyfunctionalized chiral building blocks δ-amino β-keto esters (S S, R)-(+)-5 or (R s, S)-(-)-5 is described. Key steps in the synthesis are the stereoselective reductions of b-phenylpiperidine-2,4-dione (6) and N-sulfinyl δ-amino β-keto esters 5 to cis-4-hydroxy 2-piperidinone 7 and syn-δ-amino β-hydroxy ester 9, respectively. The only protecting/deprotecting group chemistry required is related to the oxidation step.