Synthesis and Antiproliferative Activities of OSW‐1 Analogues Bearing 2”‐O‐p‐Acylaminobenzoyl Residues^†

Abstract

A library of OSW‐1 analogues bearing 2”‐O‐p‐acylaminobenzoyl residues were synthesized, and some compounds showed extremely potent antiproliferative activities and could be used as fluorescent probes.

Direct Synthesis of 2,6‐Dideoxy‐β‐glycosides and β‐Rhamnosides with a Stereodirecting 2‐(Diphenylphosphinoyl)acetyl Group

“…In fact, using 2‐OBn 23 would also make the subsequent replacement of benzoyl with DPPA group more straightforward for the preparation of trisaccharide donor (Scheme 4). Thus, trisaccharide 24 was treated with MeONa to remove the benzoyl group, and then DPPA group was introduced to this bulky O3 in the presence of 2,4,6‐trichlorobenzoyl chloride in high yields [30] . After conversion of the resulting DPPA‐installed trisaccharide 26 to PTFAI donor 27 , we carried out the key [3+3] glycosylation of trisaccharide acceptor 25 under the stand conditions (0.1 equiv of TMSOTf, PhCF 3 , −25 °C to rt).…”

“…Thus, trisaccharide 24 was treated with MeONa to remove the benzoyl group, and then DPPA group was introduced to this bulky O3 in the presence of 2,4,6-trichlorobenzoyl chloride in high yields. [30] After conversion of the resulting DPPA-installed trisaccharide 26 to PTFAI donor 27, we carried out the key [3+3] glycosylation of trisaccharide acceptor 25 under the stand conditions (0.1 equiv of TMSOTf, PhCF 3 , À 25 °C to rt). Gratifyingly, the reaction remained to be β-specific (β/α > 20 : 1, 1 J C,H = 158 Hz for βanomer) and led to the desired hexasaccharide 28 in 87 % yield.…”

Facile Synthesis of Saikosaponins

“…We envisioned the assembly of saikosaponins ( 1 – 7 ) from two pieces, i.e., a saikogenin derivative and a glycosyl donor ( Scheme 1 ) [ 21 ]. Considering the susceptibility of the 13,28-epoxy-ether moiety in the aglycones, we planned to employ glycosyl o -alkynylbenzoates as donors that can proceed glycosylation under the mild gold(I)-catalyzed conditions.…”

Collective Synthesis and Cytotoxicities of Wentilactone Type Norditerpenoid Dilactones

“…Employing the WST-8 based cell viability assay, [36][37] we measured the inhibitory activities of the synthetic norditerpenoid dilactones, including the naturally occurring WA (2), WB (3), asperolide B (4), 5, CJ-14445 (6), and the synthetic analogs (1, 7-31) against four representative tumor cell lines, i. e., PANC-1 (human pancreatic cancer cells), U87 (brain glioma U87 cells), MHCC-87H (human highly metastatic hepatocellular carcinoma cells), and A375 (human melanoma cells). Compounds were first tested at 10 μM against the four cell lines; those reduced the cell viability by more than 50% were further applied to determine the IC 50 values (see SI for details).…”