308357-84-8Relevant academic research and scientific papers
Total Syntheses of Epothilones B and D
Mulzer, Johann,Mantoulidis, Andreas,Oehler, Elisabeth
, p. 7456 - 7467 (2007/10/03)
Total syntheses of the microtubule stabilizing antitumor drugs epothilone B and D are described, starting from optically pure (S)-malic acid and methyl (R)-3-hydroxy-2-methylpropionate. The synthesis is highly convergent by coupling the three fragments C1-C6 (fragment D), C7-C10 (fragment C), and C11-C21 (fragment B). Key steps are two stereoselective Wittig type olefinations to generate the 12,13- and 16,17-double bonds, an enantioselective Mukaiyama aldol addition to synthesize fragment D, and a sulfone anion allyl iodide alkylation to connect fragments B and C. Finally fragment D was attached to the B + C fragment via aldol addition.
Synthesis of polyhydroxylated pyrrolizidine alkaloids of the alexine family by tandem ring-closing metathesis-transannular cyclization. (+)-Australine
White,Hrnciar
, p. 9129 - 9142 (2007/10/03)
Dienes 23 and 54, prepared from epoxy alcohol 9 via oxazolidinones 15 and 51, respectively, underwent ring-closing metathesis with Grubbs's catalyst to give azacyclooctenes 26 and 55. Treatment of each azacyclooctene with m-chloroperoxybenzoic acid afforded β-epoxide 28 from 26 and α-epoxide 61 from 60. Basic hydrolysis of each of these oxazolidinones was accompanied by transannular attack at the epoxide by nitrogen, resulting in 2-(O-benzyl)-7-deoxyalexine (29) and 1,2-di-(O-benzyl)australine (62). The latter was converted to the alkaloid australine (3) upon hydrogenolysis. Attempts to effect ring-closing metathesis of dienes 37, 38, and 46 were unsuccessful, suggesting that, while one allylic oxygen substituent can be tolerated by Grubbs's catalyst, two cannot.
Epothilone B and its derivatives as novel antitumor drugs: Total and partial synthesis and biological evaluation
Mulzer, Johann
, p. 205 - 238 (2007/10/03)
Microtubule stabilizing natural products, as exemplified by paclitaxel (taxolR), are being considered as novel drugs against malignant therapy resistent solid tumors. Among these compounds, epothilone B and some of its derivatives have emerged as particularly promising candidates for industrial development. The total and partial syntheses of these compounds are described in detail, and some of the most important recent results on their biological activity are discussed.
Total Synthesis of Halicholactone and Neohalicholactone
Critcher, Douglas J.,Connolly, Stephen,Wills, Martin
, p. 6638 - 6657 (2007/10/03)
The total synthesis of the marine natural products neohalicholactone (1) and halicholactone (2), in enantiomerically pure form, are reported. Key steps in the synthesis of each compound include a cis-selective Wittig reaction, stereoselective cyclopropanation, nine-membered lactone formation using the Yamaguchi method and late-stage stereoselective Cr(II)/Ni(II) mediated coupling of vinyl iodides 39 and 50 with aldehyde 14. In the case of the neohalicholactone synthesis the two major components which were coupled in this convergent synthesis were each derived from the enantiomers of commercially available malic acid. The synthesis served to confirm the original assignment of absolute configuration which was made by Yamada and Clardy. We also demonstrated, through the preparation of diastereoisomers, that another reported compound closely related to neohalicholactone is likely to be the C-15 epimer 67.
