主权项 |
1. A compound of formula I: wherein:
n is 2 to about 10;R1 is aryl or heteroaryl;R2 is aryl or heteroaryl;Ra and Rb are each independently H, alkyl, aryl, heteroaryl, or a nitrogen protecting group;wherein any alkyl, aryl or heteroaryl is unsubstituted or is substituted with 1 to 3 substituents selected from the group consisting of amino, nitro, cyano, halo, alkyl, trifluoromethyl, alkoxy, aryl, and NRcRd or any combination thereof;wherein Rc and Rd are each independently hydrogen, alkyl, or C(═O)ORe wherein Re is H or alkyl;or a salt thereof. |