- CAS Registry Number: 796073-69-3
Ravtansine (DM4) is a maytansinoid, a chemical derivative of maytansine being investigated as the cytotoxic payload of a number of antibody-drug conjugates (ADCs).
The anticancer properties of maytansinoids have been attributed to their ability to disrupt microtubule function. The maytansinoid emtansine (DM1), for example, binds at the ends of microtubules and thereby suppress their dynamic instability.
Other maytansinoids include:
- Mertansine/emtansine (DM1)
- Ravtansine/soravtansine (DM4)
The complex structures of maytansinoids coupled with their potent cytotoxicity and potential for cancer treatment stimulated great interest in their total synthesis in the decade following their initial discovery in the 197o’s. 
 Cassady JM, Chan KK, Floss HG, Leistner E. Recent developments in the maytansinoid antitumor agents. Chem Pharm Bull (Tokyo). 2004 Jan;52(1):1-26.