Studies towards the total synthesis of mumbaistatin: synthesis of highly substituted benzophenone and anthraquinone building blocks
摘要:
Model compounds and building blocks for a planned total synthesis of the highly potent glucose-6-phosphate (G6P) translocase inhibitor mumbaistatin (1) and structural analogs were elaborated: compound 1 represents a lead structure in the development of potential new antidiabetic drugs. With the model substrate 20 it was demonstrated that highly functionalized, tetra-ortho-substituted benzophenones can be prepared by nucleophilic addition of an aryllithium-building block to a benzaldehyde followed by oxidation. For compound 37, a potential precursor of the anthraquinone part of mumbaistatin, various approaches via aryne/phthalide annulations were developed and evaluated. The required functionalized arenes were prepared exploiting, among others, regioselective bromination and ortho-lithiation reactions. Coupling reactions of the anthracene-carbaldehyde 44 derived from 37 with various metalated arenes proved to be unexpectedly difficult and failed so far. (C) 2003 Elsevier Science Ltd. All rights reserved.
Efficient enantio-selective synthesis of conformationally constrained diacylglycerol analogues, 7-substituted isobenzofuranone derivatives, originally developed by us as PKC alpha ligands, was achieved by asymmetric dihydroxylation and gamma-lactone formation via ortho-lithiation and carboxylation. A series of derivatives having straight and/or branched side chains were synthesized and evaluated, and low-nanomolar-concentration affinity ligands and highly potent PKC alpha activators were found among them. These potent ligands induced phenotypic change of K562 cells, which is characteristic of PKC activators. (C) 2009 Elsevier Ltd. All rights reserved.