A SAR study around the P3 group in the lead 4 led to the identification of a rigid indole-2-carbonyl unit as one of the best P3 moieties ( 5c ) .
that a methoxy substitution at the 4-position on the indole unit was highly favorable for enhancing the inhibitory potency .
A SAR study around the P3 group in the lead 4 led to the identification of a rigid indole-2-carbonyl unit as one of the best P3 moieties ( 5c ) .
Further optimization showed that a methoxy substitution at the 4-position on the indole unit was highly favorable for enhancing the inhibitory potency .