ANSAMACROLIDES

A large number of ansamacrolides, exemplified by maytansine, 8, have potent antitumor activity. Maytansine has been subjected to clinical studies in the NCI program and has been disappointing as an anticancer agent. Furthermore, it has been shown to be quite toxic. Analogue development may produce a more useful and less toxic antitumor agent in the future (881). 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Deterniined in CHCl unless otherwise noted. Originally called streptovaricin F. 

Streptovaricins. The streptovaricins are produced by Streptomjces spectablis n. sp. (60,61) and are isolated as a crude complex (62,63). Substance B 44 P, isolated from Streptomjces B 44-Pl, was shown to be identical with the streptovaricias (64). 

AnsamacroHde CAS Registry Number Producing organism Molecular formula MP, °C Mb Stmctu re no. Referen ce 

Streptomjces diastochromogenes (variabilicolor) Streptomjces diastochromogenes (variabilicolor) Nocardia mediterranei var. kanglensis 1747-64 Streptomjces albolongus C 46466 Streptomjces albolongus C-46366 

Streptonjces hjgroscopicus. AM-3672 Streptonjces hjgroscopicus. AM-3672 Streptotrjces hjgroscopicus JSM-3672 ISocardia sp. C-14919 (N-2001) 

Streptomjces rishirensis T-23 Streptomjces rishirensis T-23 Streptomjces rishirensis T-23 Streptomjces rishirensis T-23C Streptomjces rishirensis T-23 

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