Synthesis and antitumor properties of amino acids acylated with 2-methyl-3-oxo-1-phenyl-1cyclopentane carboxylic acid

Abstract

Acylation of the silyl esters of amino acids, specifically glycine, b-alanine, sarcosine, glycylglycine, and 6-aminopenicillanic acid, with 1-phenyl-3-oxo-2-methyl-1-cyclopentane carboxylic acid chloride yielded new analogs of the known antitumor antibiotic sarcomycin. The resulting compounds had high levels of antitumor activity.

Enantioselective [3 + 2] Cycloaddition of Allenes to Acrylates Catalyzed by Dipeptide-Derived Phosphines: Facile Creation of Functionalized Cyclopentenes Containing Quaternary Stereogenic Centers

“…Creation of quaternary stereocenters is a challenging task in organic synthesis, and we recently became interested in devising organocatalytic methods to access molecules with chiral quaternary centers . Five-membered carbocycles with a quaternary stereogenic center are interesting substructures often found in many natural products and bioactive molecules (Scheme ); we envisioned that phosphine-catalyzed [3 + 2] annulations between α-substituted acrylates and allenes may be utilized to construct such five-membered ring systems. Our group has been actively investigating asymmetric organic transformations that can be promoted by organocatalysts derived from primary amino acids in the past few years, − , and thus, we have keen interest in deriving versatile amino acid-based novel phosphines.…”

“…The optically enriched functionalized cyclopentenes 7 are valuable molecules, due to the importance of five-membered ring structures in natural products and medicinal chemistry. , With the established synthetic protocols, , such structures are also attractive synthetic intermediates. As oxindoles are important structural scaffolds in pharmaceutical industry, synthetic value of the cycloaddition products was further demonstrated by converting 7j into a spiral oxindole.…”

Understanding the Mechanism of the Lewis Acid Promoted [3 + 2] Cycloaddition of Propargylic Alcohol and α-Oxo Ketene Dithioacetals

“…Functionalized five-membered carbocycles as structural motifs are often found in a large number of natural products and bioactive molecules. − The [3 + 2] cycloaddition reactions have attracted increasing interest in organic chemistry due to their wide application in the synthesis of various compounds with five-membered rings. , Among many impressive methods, transition-metal and phosphine-catalyzed [3 + 2] cycloaddition provide a powerful synthetic approach to obtain cyclopentadienes and cyclopentenes. , Despite the above significant achievements, the design and development of novel catalyst-mediated processes, beginning with easily available materials to afford densely functionalized cyclopentadienes, are still of great value. Very recently, the Bi group reported a new class of fully substituted 2,5-dialkylthio cyclopentadienes using α-oxo ketene dithioacetals as the polarized alkene component instead of classic alkylthio displacement reactions for the synthesis of carbocycles.…”

Phosphine-Catalyzed [3 + 2] Cycloaddition of 4,4-Dicyano-2-methylenebut-3-enoates with Benzyl Buta-2,3-dienoate and Penta-3,4-dien-2-one

“…Five-membered carbocycles with a quaternary stereogenic center are interesting substructures often found in many natural products and bioactive molecules, − and we recently became interested in exploring organocatalytic methods to access highly functionalized cyclopentenes bearing one all-carbon quaternary stereogenic center . It is known that phosphine-catalyzed [3 + 2] annulations between α-substituted acrylates and allenes may be utilized to construct such five-membered ring systems (Scheme ).…”