Preparation of isopropylidene acetals from butane-1,2,4-triol and its cyclopropane congeners

New Hybrids Derived from Podophyllic Aldehyde and Diterpenylhydroquinones with Selectivity toward Osteosarcoma Cells

“…About the cyclolignans, podophyllotoxin, 1, can be easily transformed into picropodophyllic acid, as previously described by us. 16 In order to avoid the relactonization to the corresponding cis-lactone during esterification, picropodophyllic acid was protected as acetonide 24 to get the acid 8. This protecting group can be easily removed after condensation with the alkylated DNHQ 9−11 (Scheme 2).…”

New synthesis of syn-stereodiad building block for polyketides. Formal synthesis of arenamides A and C

“…The starting compound for the synthesis of 2 was (7S)-7-(3-bromoprop-1-en-2-yl)-5,5-dimethyl-4,6-dioxaspiro [2.5]octane (4). It was obtained in enantiomerically pure form according to the previously described scheme [32,33] from diethyl (S)-malate in six preparative steps using the DOI: 10.1134/S107042801504020X R = Ph, R′ = C 6 H 13 (a), Bu (b); R = MeSCH 2 , R′ = C 6 Kulinkovich reaction [34][35][36][37][38][39][40] and cationic cyclopropyl-allyl isomerization of the corresponding cyclopropyl methanesulfonate [41][42][43]. Compound 4 was used previously as a chiral precursor of key building blocks for the synthesis of epothilones 5 and cryptophycins 6 which exhibit pronounced Taxol-like activity (Scheme 2) [30,31].…”