What is Ethanesulfonic acid - methyl (3Z)-3-{[(4-{methyl[(4-methyl-1-piperazinyl)acetyl]amino}phenyl)amino](phenyl)methylene}-2-oxo-6-indolinecarboxylate (1:1) (CAS: 656247-18-6)?

Ethanesulfonic acid - methyl (3Z)-3-{[(4-{methyl[(4-methyl-1-piperazinyl)acetyl]amino}phenyl)amino](phenyl)methylene}-2-oxo-6-indolinecarboxylate (1:1) is a complex organic compound with the CAS number 656247-18-6. It contains a sulfonic acid group, a methyl ester, and a substituted indoline ring, making it a potential pharmaceutical intermediate. The compound is typically a solid at room temperature and exhibits solubility in polar organic solvents. Its molecular structure suggests it may have applications in drug development due to its functional groups and potential biological activity.