First Total Synthesis of Antitumor Natural Product (+)- and (−)-Pericosine A:  Determination of Absolute Stereo Structure^†

Abstract

The first total synthesis of (+)- and (-)-pericosine A has been achieved, enabling the revision and determination of the absolute configuration of this antitumor natural product as methyl (3S,4S,5S,6S)-6-chloro-3,4,5-trihydroxy-1-cyclohexene-1-carboxylate. Every step of this total synthesis proceeded well with excellent stereoselectivity. Structures of the intermediates in crucial steps were confirmed by detailed 2D NMR analysis.

Divergent Synthesis and Evaluation of Inhibitory Activities against Cyclooxygenases-1 and -2 of Natural Withasomnines and Analogues

“…24) Because of these interesting biological activities, several reports of the synthesis of 1a were disclosed. [27][28][29][30][31][32][33][34][35][36] In the course of our synthetic studies of small natural products and their analogues, [37][38][39][40][41][42] we recently reported the divergent synthesis of withasomnines 1a-c and their analogues via 4-hydroxypyrazole intermediates in a preliminary communication. 43) We herein describe the details of the divergent synthesis of natural 1a-c as well as nine withasomnine analogues 1d-l, which were easily prepared by the Suzuki-Miyaura coupling of key intermediate 16.…”

Synthesis of Marine-Derived Carbasugar Pericosines

“…The first total synthesis of (À)-1 was achieved as shown in Scheme 4 [77,84]. Alcohol 15 derived from (À)-shikimic acid underwent Dess-Martin oxidation, affording b,g-unsaturated ketone 47.…”

“…The synthesis of (þ)-pericosine A [(þ)-1] was carried out following Scheme 5 [77]. Preparation of (þ)-48 (as opposed to (-)-48 in the preceding synthesis) from (-)-quinic acid has been previously reported.…”

“…Preparation of (þ)-48 (as opposed to (-)-48 in the preceding synthesis) from (-)-quinic acid has been previously reported. In our synthesis, the method of preparation of (þ)-48 was a slight modification of that which appeared in the literature [77]. Treatment of hyroxylactone 59 with NaOMe in MeOH followed by neutralization with DOWEX ® 50W-X8 gave crude diol 60, which was obtained by simple filtration and used in the subsequent reaction without further extraction or purification.…”

Glaucocalyxin A inhibits the growth of liver cancer Focus and SMMC-7721 cells

“…Natural compounds have been revealed to be beneficial when used alone or in combination with conventional therapies for the prevention of tumor progression or treatment of human malignancies (7). Since the 1940s, 48.6% of all cancer therapeutic agents approved by the US Food and Drug Administration and similar organizations are natural products or direct derivatives (8).…”