Table 1.

Inhibition of human neutrophil elastase by derivatives of compound (I)^ab

Compound	R3	kobs/[I] M−1 s−1
8	p-Cl	20
9	p-F	320
10	p-OCH3	70
11	p-NH2	110
12	p-NHBoc	170
13	p-NHCO(CH2)2COOH	300
14	p-NHCO(o-COOH)C6H4	260
15	p-NHCONH(CH2)2Ph	150
16c	p-Cl	4580d

^aR₁=n-propyl, R₂=methyl for all, unless indicated otherwise;

^bused as diastereomeric mixtures;

^cR₁=isobutyl, R₂=methyl;

^ddetermined using the progress curve method and expressed as k_inact/K_I M⁻¹ s⁻¹ (see Experimental section).