Acetyl Chloride-mediated Mild and Chemoselective Attachment and Removal of Tetrahydropyranyl (THP) Group

Abstract

A mild, chemoselective and convenient method for the formation and deprotection of tetrahydropyranyl ethers is described. With 1-5 mol% of acetyl chloride and slightly excess dihydropyran in methylene chloride or in neat dihydropyran, the formation of THP ethers from the corresponding alcohols was accomplished in the presence of many acid-sensitive functional groups. Efficient cleavage of THP ethers was also accomplished with the same reagent by switching the solvent to methanol.

Synthesis of new pyrazolo[4,3-a]phenanthridine Pim-1 inhibitors and evaluation of their cytotoxic activity towards the MOLM-13 acute myeloid leukemia cell line

“…Pyrazolo [4,3-a]phenanthridines 14 and 15 were obtained by Suzuki crosscoupling/cyclization using 2-formylboronic acid. 4,11 Next, cleavage of the THP group in acidic conditions 12 Two other new derivatives were also prepared from VS-II-173 (Scheme 2). The first one was 1-iodo analogue 20, prepared to evaluate the feasibility of further functionalization at this position using palladium cross-couplings.…”