203250-25-3Relevant academic research and scientific papers
Cyclization strategies for the synthesis of macrocyclic bisindolylmaleimides
Faul,Krumrich
, p. 2024 - 2033 (2007/10/03)
Three new approaches to the synthesis of macrocyclic bisindolylmaleimides 1-4 have been identified. Two strategies afford 8, the penultimate intermediate for the synthesis of 1-4, in 73% and 32% yield by intramolecular cyclization of 31 and 40, respectively. The optimum synthesis of 1 was achieved in nine steps and 15% yield by intramolecular formation of the macrocycle and maleimide in one step by reaction of the sodium indolate of 12 with methyl indole-3-glyoxylate 47. The mechanism of this reaction has been elucidated, using the trityl-protected derivative, to involve initial formation of the tricarbonyl imide 48, followed by irreversible alkylation of the indole nitrogen to generate the 17-membered macrocycle 49. Cyclization of 49 to hydroxymaleimide 50 and subsequent dehydration afforded 8a. This approach eliminated the problem of dimerization observed in the intramolecular cyclization reactions.
Macrocyclic bisindolylmaleimides: Synthesis by inter- and intramolecular alkylation
Faul, Margaret M.,Winneroski, Leonard L.,Krumrich, Christine A.,Sullivan, Kevin A.,Gillig, James R.,Neel, David A.,Rito, Christopher J.,Jirousek, Michael R.
, p. 1961 - 1973 (2007/10/03)
Macrocyclic bisindolylmaleimides 1-4 have been identified as competitive reversible inhibitors of PKC β1 and β2 and are being advanced to the clinic for evaluation as a treatment of retinopathy associated with diabetic complications. Highly convergent and stereoselective syntheses of 1-4 have been developed. The key synthetic step involves intermolecular alkylation of symmetrical bisindolylmaleimide 9 with chiral bisalkylating agent 8c and is amenable to the preparation of multikilogram quantities of these compounds. The synthetic sequence to 1, the most active the compound, proceeds in 11 steps and 26% overall yield (> 98% ee) from (R)-1-chloro-2,3-propanediol. No chromatographic purifications are required throughout the process and the final product is isolated in >97% purity after crystallization from DMF/MeOH. Synthesis of 1-4 by intramolecular alkylation proved less efficient, requiring 17 steps and affording 1-4 in lower overall yields of 6.0-8.5%.
