- PREPARATION OF MAYTANSINOID ESTERS
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Provided are efficient methods for direct coupling of a maytansinoid with a carboxylic acid to prepare a maytansinoid C-3 ester in high yield using a rare earth metal-based or trifluoromethanesulfonate-based Lewis acid catalyst and a base together with a coupling reagent. Also provided are compositions used in such methods.
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Paragraph 0442; 0443
(2014/07/08)
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- Method for the preparation of maytansinoid esters
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Improved processes for the preparation and purification of maytansinoid esters, especially thiol and disulfide-containing maytansinoids are described. In one aspect the process comprises a process of making a maytansinoid ester comprising forming an anion of maytansinol or a maytansinoid bearing a free C-3 hydroxyl moiety and reacting the anion with an activated carboxyl compound to thereby produce the maytansinoid ester.
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Page/Page column 4
(2008/06/13)
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- Structural requirements for antileukemic activity among the naturally occurring and semisynthetic maytansinoids.
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In an effort to determine the structural requirements for the significant antileukemic, cytotoxic, antitubulin, and antimitotic activity exhibited by the novel ansa macrolide, maytansine (1), four new C-3 ester and six new C-9 ether homologues were synthesized. The biological activities of these compounds were assayed and compared to the activities of previously reported, naturally occurring maytansinoids. From the data, it is apparent that presence of the C-3 ester is necessary for significant activity, and variations in the ester group are not accompanied by marked changes in activity. However, elimination of the ester group, as in maytansinol (7), maysine (8), normaysine (9), and maysenine (10), results in a significant decrease in biological activity. Blockage of the C-9 carbinolamide via etherification markedly reduces antileukemic and cytotoxic activity and slightly reduces antitubulin activity but has relatively little effect on antimitotic activity against sea urchin eggs. Thus, a free carbinolamide at C-9 is advantageous for optimal activity.
- Kupchan,Sneden,Branfman,Howie,Rebhun,McIvor,Wang,Schnaitman
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