Structure–activity relationship studies on acremomannolipin A, the potent calcium signal modulator with a novel glycolipid structure 3: Role of the length of alditol side chain

Introducing Lipophilicity to (Polyhydroxyalkyl)thiazolidine Carboxylic Acids Via Acylation

“…The aldehyde protection was performed with ethanethiol and 37% HCl ( Scheme 1 ) to achieve the corresponding open-chain derivative of d -(−)-ribose 5 with the free hydroxyl groups. 18 , 19 The low yield after recrystallization from acetone was in accordance with the literature. 15 …”

“…The first step consisted of the protection of the carbonyl group of d -(−)-ribose to avoid the reactivity of the carbonyl group while maintaining its functionality until the cyclization step with l -cysteine. The aldehyde protection was performed with ethanethiol and 37% HCl (Scheme ) to achieve the corresponding open-chain derivative of d -(−)-ribose 5 with the free hydroxyl groups. , The low yield after recrystallization from acetone was in accordance with the literature …”

Stereoselective β-mannosylation via anomeric O-alkylation: Formal synthesis of potent calcium signal modulator acremomannolipin A

“…5 In 2015, the same group also prepared five homologs of acremomannolipin A bearing alditols of different length and found that the length of the alditol side chain was a crucial determinant for the potent calcium signal modulating activity. 6 Early 2015, Li and coworkers reported another total synthesis of acremomannolipin A in which key intermediate β-mannoside 7 was obtained via gold(I)-catalyzed glycosylation 7 between 4,6-O-benzylideneprotected D-mannose-derived ortho-alkynylbenzoate donor 5 and acceptor 6 in 85% yield (β/α = 13/1). 8 In 2016, the Toshima group described the third total synthesis of acremomannolipin A in which key intermediate β-mannoside 10 was obtained via borinic acid-catalyzed glycosylation between 1,2-anhydromannose donor 8 and acceptor 9 in 99% yield (β only).…”