152845-27-7Relevant academic research and scientific papers
Solid-Phase Synthesis of Triostin A Using a Symmetrical Bis(diphenylmethyl) Linker System
Sable, Ganesh A.,Lim, Dongyeol
, p. 7486 - 7494 (2015/08/18)
Triostin A is a symmetric bicyclic depsipeptide with very potent antitumoral activity because of its bisintercalation into DNA. In this study, we report a new synthetic strategy that exploits a structural symmetry of triostin A. First, we prepared a novel symmetric linker molecule that is labile under mildly acidic conditions and suitable for a solid-phase synthesis procedure. Two Cys units were attached to a linker-resin conjugate via their free thiol groups, and double deprotection and double coupling reactions were then applied to synthesize linear tetradepsipeptides. Subsequently, the key biscyclization of the tetradepsipeptides was performed on the resin, and the resulting cyclic octapeptide was detached from the linker-resin conjugate to give a peptide with two free thiols. Finally, triostin A was obtained by oxidizing the free thiols in solution to produce a disulfide. The yield was improved through exploration of two different solid-phase synthetic approaches under similar strategy. Mainly, this strategy was developed to enable the ease and rapid preparation of libraries of symmetric bicyclic depsipeptides. It also addresses several synthetic problems with our synthesis, including diketopiperazine (DKP) formation, poor cyclization yields and preparation of noncommercial N-methyl amino acids in good yields.
Synthesis of a new class of difunctional tetraphenylene crown ethers
Gibson, Harry W.,Nagvekar, Devdatt S.,Delaviz, Yadollah,Bryant, William S.
, p. 1429 - 1436 (2007/10/03)
Three new substituted tetraphenylene crown ethers have been made. Bis(5- carbomethoxy-1,3-phenylene)-bis(p-phenylene)-(3x + 6)-crown-x, where x = 12, 16, and 20 (11b-11d) were synthesized via [1 + 1] cyclization of methyl 3,5- bis[ω-chloro(oligoethyleneoxy)]benzoates (13b-3d) with methyl 3,5-bis[ω- (p-hydroxyphenoxy)(oligoethyleneoxy)]benzoates (16b-6d) using K2CO3 as base and tetrabutylammonium iodide as a phase transfer agent in dimethylformamide (DMF). The corresponding 30-membered (x = 8) macrocycle 11a could not be made by this approach; only the elimination product, 3,5-bis(vinyloxy)benzoic acid (19), was isolated. 16a-16d were made via alkylation of p-benzyloxyphenol (14) with 13a-13d, respectively, followed by hydrogenolysis with Pd/C as catalyst. No complexation of these macrocycles with dibenzylammonium ions was detected by NMR spectroscopy, but weak complexation of 11d with a paraquat derivative was observed.
