22323-80-4Relevant articles and documents
Stereoselective synthesis of the a-ring of armatol a from a bromo-substituted chiral building block based on Ireland-claisen rearrangement and ring-closing olefin metathesis
Hirose, Yuta,Fujiwara, Kenshu,Saito, Takafumi,Katoono, Ryo,Suzuki, Takanori
, p. 76 - 103 (2015)
The stereoselective synthesis of the A-ring of armatol A, a natural polycyclic ether triterpene from the red alga Chondria armata, was achieved in a non-biomimetic way. The synthesis employed Ireland-Claisen rearrangement of an ester, prepared from a bromo-substituted chiral building block, for the construction of C6 and C7 stereocenters and a relay ring-closing olefin metathesis for the seven-membered ring formation.
Chemoenzymatic Access to Chiral Tetrols Produced by Thiamine Diphosphate Dependent Benzaldehyde Lyase
Zecevic, Damir,Germer, Philipp,Walter, Lydia,Gauchenova, Ekaterina,Müller, Michael
, p. 6465 - 6468 (2018)
Highly functionalized polyol building blocks have been synthesized by means of stereoselective chemoenzymatic C–C bond formation followed by stereoselective reduction. Catalysis by thiamine diphosphate (ThDP) dependent benzaldehyde lyase (BAL) with glyceraldehyde acetonide as acceptor substrate gave highly stereoenriched polyols such as (1S,2S,3R)-1-phenylbutane-1,2,3,4-tetrol (1), the 3,4-protected anti-1,2-diol 5, and the precursor of both compounds, 2-hydroxyketone 4.
Total Synthesis of Euonymine and Euonyminol Octaacetate
Hagiwara, Koichi,Inoue, Masayuki,Nagai, Toshiya,Wang, Yinghua,Watanabe, Itsuki
supporting information, p. 21037 - 21047 (2021/12/17)
Euonymine (1) and euonyminol octaacetate (2) share the core structure of euonyminol (3), the most hydroxylated member of the dihydro-β-agarofuran family. In 2, eight of the nine hydroxy groups of 3 are acetylated, and 1 has six acetyl groups and a 14-membered bislactone comprising a pyridine dicarboxylic acid with two methyl groups. The different acylation patterns provide distinct biological activities: 1 and 2 display anti-HIV and P-glycoprotein inhibitory effects, respectively. The 11 contiguous stereocenters and 9 oxygen functionalities of the ABC-ring system of 1 and 2 represent a formidable challenge, which is further heightened by the macrocyclic structure of 1. Here we disclose an efficient synthetic strategy for enantioselective total synthesis of 1 and 2. Starting from (R)-glycerol acetonide, we constructed the B-ring by an Et3N-accelerated Diels-Alder reaction, the C-ring by intramolecular iodoetherification, and the A-ring by ring-closing olefin metathesis. The 10 stereocenters were installed through a series of substrate-controlled stereoselective C-C and C-O bond formations by exploiting the three-dimensional structures of judiciously designed substrates. These newly developed reaction sequences led to protected euonyminol 5, which served as a common intermediate for assembling 1 and 2. Global deprotection of 5 and subsequent acetylation produced 2. Alternatively, the discriminative protective groups of 5 allowed for site-selective bis-esterification to generate bislactone. Combining [3 + 2]-cycloaddition and reductive desulfurization introduced the last remaining stereocenters of the two methyl groups on the macrocycle. Finally, deprotection and acetylation gave rise to fully synthetic 1 for the first time.
Preparation method of intermediate of antitumor drug gemcitabine hydrochloride
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, (2020/10/14)
The invention relates to a preparation method of a intermediate of antitumor drug gemcitabine hydrochloride. According to the method, D-isoascorbic acid is used as a starting raw material and reacts with 2,2-dimethylpropane under the catalysis of p-toluenesulfonic acid in the presence of acetone serving as a solvent to protect hydroxyl groups at 5 and 6 sites to obtain T1; then, hydrogen peroxideis used for carrying out oxidation under the alkaline condition to obtain T2; the T2 is oxidized by sodium hypochlorite to obtain T3; the T3 and ethyl bromodifluoroacetate are subjected to a Reformatsky reaction to obtain T4; then the T4 is subjected to deprotection and cyclization under the catalysis of trifluoroacetic acid to obtain T5; the T5 and benzoyl chloride are subjected to an esterification reaction under the catalysis of DMAP to obtain T6, and a synthetic route II is shown in the specification.