Patent ID: 6911471

Claim:
A compound having anti-cancer activity comprising: wherein R 1 and R 2 are independently alkyls with 1-10 carbon atoms; X is S or Se; R 3 is —H, —COOH, —CH 2 —COOH, —CH 2 —CH 2 —COOH, —CH(CH 3 )—COOH, —CH(CH 2 —CH 3 )—COOH, or —CH 2 —CH 2 —CH 2 —COOH; n is 0 or 1; R 4 is —OH, —H, or —CH 3 , R 3 and R 4 form an unsubstituted or substituted aromatic ring with C 1 and C 2 ; and R5 is a —OH, or Glycine substituent; or a pharmaceutically acceptable salt thereof.