No abstract

The stereoselective synthesis of the southern fragment (C21-C41) of Hantupeptin A is described. The required stereochemistry of β-hydroxy-α-methyl acid unit was accomplished through the Aldol reaction using Evan's chiral auxiliary followed by the installation of the terminal alkyne with Ohira-Bestmann reagent.

A series of novel (5R)-5-((2S,3S)-3-((1-(4-chlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-3,6-dihydro-2H-pyran-2-yl)-3-(4-fluorophenyl)-2,6-diphenyl-3,3a,5,6-tetrahydro-2H-pyrazolo[3,4-d]thiazoles 11a–g and (5R)-5-((2S,3S)-3-((1-(4-chlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-3,6-dihydro-2H-pyran-2-yl)-3-(4-fluorophenyl)-6-phenyl-3,3a,5,6-tetrahydroisoxazolo[3,4-d]thiazoles 12a–g were synthesized by the reaction of chalcone derivatives of (R,Z)-2-((2S,3S)-3-((1-(4-chlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-3,6-dihydro-2H-pyran-2-yl)-5-(4-fluorobenzylidene)-3-phenylthiazolidin-4-ones 10a–g with phenylhydrazine and hydroxylamine hydrochloride. The chemical structures of newly synthesized compounds were elucidated by IR, NMR, MS and elemental analysis. The compounds 11a–g and 12a–g were evaluated for their antibacterial activity and antifungal activity.

In a one pot procedure a series of (R)-2-((2S,3S)-3-((1-(4-chlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-3,6-dihydro-2H-pyran-2-yl)-3-phenylthiazolidin-4-ones 9a-g and 2-((2R)-2-((2S,3S)-3-((1-(4-chlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-3,6-dihydro-2H-pyran-2-yl)-4-oxo-3-phenylthiazolidin-5-yl)acetic acids 10a-g was prepared by condensation of (2S,3S)-3-((1-(4-chlorophenyl)-1H-1,2,3-triazol-4-yl)methoxy)-3,6-dihydro-2H-pyran-2-carbaldehyde with mercapto acids and primary amines in the presence of ZnCl 2 under both microwave irradiation and conventional heating conditions. Characterization of new compounds has been done by means of IR, NMR, MS and elemental analysis. The cytotoxicity was assessed against a panel of four different human tumor cell lines: A549 derived from human alveolar adenocarcinoma epithelial cells (ATCC No. CCL-185), Hela derived from human cervical cancer cells (ATCC No. CCL-2), MDA-MB-231 derived from human breast adenocarcinoma cells (ATCC No. HTB22) and HEK 293 (normal human embryonic kidney cell line) using the MTT assays. Among the tested compounds 9e and 10e showed the most potent activity against MCF-7 breast cancer cell line with IC 50 values of 1.91 and 1.95 μΜ, whereas 9b, 10b, 9g and 10g showed promising activity against MDA-MB-231 and Hela cell lines with IC 50 values of 5.84, 5.74, 7.89 and 7.65 μΜ, respectively.