210299-19-7Relevant articles and documents
First total synthesis of ampullosine, a unique isoquinoline alkaloid isolated from Sepedonium ampullosporum, and of the related permethylampullosine
Vargas, Didier F.,Larghi, Enrique L.,Kaufman, Teodoro S.
, p. 33096 - 33106 (2019)
A straightforward and convenient approach toward the first total synthesis of ampullosine, a structurally unique 3-methylisoquinoline alkaloid isolated from Sepedonium ampullosporum, is reported. Access to the related O-methyl ampullosine methyl ester from a common intermediate is also disclosed. The synthetic sequence toward the natural product comprised a Kolbe-type carboxylation of 3,5-dihydroxybenzoic acid and further esterification of the diacid, followed by masking of one of the phenols through selective ester reduction and subsequent acetonide formation. Installation of the three-carbon atom required for the 3-methylpyridine ring was performed by triflation of the remaining free phenol and a Pd-catalyzed Suzuki-Miyaura reaction with potassium E-propenyltrifluoroborate. Deprotection of the acetonide, followed by partial oxidation of the benzylic alcohol to the salicylaldehyde, O-methylation of the free phenol and hydrazonation of the resulting ortho-anisaldehyde derivative gave a hydrazone-based 1-azatriene. This was further subjected to 6π-azaelectrocyclization to afford permethylampullosine (11 steps, 14% overall yield), whereas exhaustive demethylation with AlI3 generated in situ gave ampullosine (12 steps, 3.2% global yield).
Enantioselective total synthesis of (+)-stachyflin: A potential anti-influenza a virus agent isolated from a microorganism
Sakurai, Junji,Kikuchi, Takuya,Takahashi, Ohgi,Watanabe, Kazuhiro,Katoh, Tadashi
, p. 2948 - 2957 (2011/06/26)
A novel and potent hemagglutinin inhibitor, (+)-stachyflin, was efficiently synthesized in an enantioselective manner starting from the (+)-5-methyl-Wieland-Miescher ketone. The synthetic method features a BF 3·Et2O-induced cascade epoxide-opening/ rearrangement/cyclization reaction tostereoselectively construct the requisite pentacyclic ring system in one step. In order to rationalize the mechanism of the cascade reaction, quantum chemical calculations of the possible intermediary carbocations and transition states in the model synthesis were carried out. An alternative approach to synthesize (+)-stachyflin by employing a similar cascade reaction was also described. A potential anti-influenza A virus agent, (+)-stachyflin, a novel hemagglutinin inhibitor, has been synthesized in an enantioselective manner for the first time starting from (+)-5-methyl-Wieland- Miescher ketone. The method features a BF3·Et 2O-induced cascade epoxide-opening/rearrangement/cyclization reaction to construct the requisite pentacyclic ring system in one step.
Total synthesis of (+)-stachyflin: A potential anti-influenza A virus agent
Watanabe, Kazuhiro,Sakurai, Junji,Abe, Hideki,Katoh, Tadashi
supporting information; experimental part, p. 4055 - 4057 (2010/08/23)
The first enantioselective total synthesis of (+)-stachyflin, a potential anti-influenza A virus agent, was achieved; the method features a BF 3·Et2O-induced domino epoxide-opening/ rearrangement/cyclization reaction to stereoselecti
First total synthesis of (±)-stachyflin
Taishi, Teruhiko,Takechi, Shozo,Mori, Sachio
, p. 4347 - 4350 (2007/10/03)
We achieved the first total synthesis of (±)-stachyflin in 29 steps, including the construction of cis-fused decalin and the formation of an etheral bond at its bridgehead as key transformations.
