The first example of the copper-catalyzed cyclization of 4-(phenylamino)-2H-chromen-2-ones employing the N-methyl moiety of DMF as the source of the methine (CH) group has been developed, providing an efficient synthetic pathway to access novel functionalized 6H-chromeno[4,3-b]quinolin-6-ones in moderate to good yields.

No abstract

Two new lanostane-type nonsulfated pentasaccharide triterpene glycosides, 17-dehydroxyholothurinoside A (1) and griseaside A (2), were isolated from the sea cucumber Holothuria grisea. Their structures were elucidated by spectroscopic methods, including 2D-NMR and MS experiments, as well as chemical evidence. Compounds 1 and 2 possess the same pentasaccharide moieties but differ slightly in their side chains of the holostane-type triterpene aglycone. The structures of the two new glycosides were established as (3b,12a)-22,25-epoxy-3-

There is a strong demand for novel native peptide motifs for post-synthetic modifications of peptides without pre-installation and subsequent removal of directing group. Herein, we report an efficient method for...