TABLE 1.

Building blocks used in the bicyclic guanidine PS-SCL^a

No.	Building block
	R1	R2	R3
1	3-Phenylbutyric acid	l-Alanine	l-Alanine
2	m-Tolylacetic acid	l-Phenylalanine	l-Phenylalanine
3	3-Fluorophenylacetic acid	Glycine	l-Isoleucine
4	p-Tolylacetic acid	l-Isoleucine	l-Lysine
5	4-Fluorophenylacetic acid	l-Lysine	l-Leucine
6	3-Metoxyphenylacetic acid	l-Leucine	l-Methionine
7	4-Metoxyphenylacetic acid	l-Methionine	l-Arginine
8	4-Ethoxyphenylacetic acid	l-Arginine	l-Valine
9	3-(3,4-Dimethoxyphenyl)-propionic acid	l-Valine	l-Tyrosine
10	4-Biphenylacetic acid	l-Tyrosine	d-Alanine
11	3,4-Dimethoxyphenylacetic acid	d-Alanine	d-Phenylalanine
12	Phenylacetic acid	d-Phenylalanine	d-Isoleucine
13	Hydrocinnamic acid	d-Isoleucine	d-Lysine
14	4-Phenylbutyric acid	d-Lysine	d-Leucine
15	Butyric acid	d-Leucine	d-Arginine
16	Heptanoic acid	d-Arginine	d-Valine
17	Isobutyric acid	d-Valine	d-Tyrosine
18	(+/−)-2-Methylbutyric acid	d-Tyrosine	l-α-Aminobutyric acid
19	Isovaleric acid	l-α-Aminobutyric acid	α-Aminoisobutyric acid
20	3-Methylvaleric acid	l-Norvaline	l-Norvaline
21	4-Methylvaleric acid	d-Norvaline	d-Norvaline
22	t-Butylacetic acid	l-Norleucine	l-Norleucine
23	Cyclohexanecarboxylic acid	d-Norleucine	d-Norleucine
24	Cyclohexylacetic acid	l-Ornithine	l-Ornithine
25	Cyclohexylbutyric acid	l-3-(2-Naphthyl)-alanine	l-3-(2-Naphthyl)-alanine
26	Cycloheptanecarboxylic acid	d-3-(2-Naphthyl)-alanine	d-3-(2-Naphthyl)-alanine
27	Lactic acid	l-Cyclohexylalanine	l-Cyclohexylalanine
28	Acetic acid	d-Cyclohexylalanine	d-Cyclohexylalanine
29	Cyclobutanecarboxylic acid	l-Methionine sulfone	l-Methionine sulfone
30	Cyclopentanecarboxylic acid	l-p-Nitrophenylalanine	l-p-Nitrophenylalanine
31	3-Cyclopentylpropionic acid	d-p-Nitrophenylalanine	l-p-Nitrophenylalanine
32	3-Cyclohexylpropionic acid	l-p-Chlorophenylalanine	l-p-Chlorophenylalanine
33	4-Methyl-cyclohexanecarboxylic acid	d-p-Chlorophenylalanine	d-p-Chlorophenylalanine
34	4-t-Butyl-cyclohexanecarboxylic acid	l-p-Fluorophenylalanine	l-p-Fluorophenylalanine
35	2-Norbornaneacetic acid	d-p-Fluorophenylalanine	d-p-Fluorophenylalanine
36	1-Adamantaneacetic acid	l-ɛ-Acetyl-lysine	l-ɛ-Acetyl-lysine
37	2-Ethylbutyric acid	l-3-Pyridyl-alanine	l-3-Pyridyl-alanine
38	3,3-Diphenylpropionic acid	d-3-Pyridyl-alanine	d-3-Pyridyl-alanine
39	2-Methyl-4-nitroimidazolepropionic acid	l-Cyclohexylglycine	l-Cyclohexylglycine
40	Cyclopentylacetic acid	d-Cyclohexylglycine	d-Cyclohexylglycine
41	Indole-3-acetic acid	l-t-Glycine	l-t-Butyl-glycine
42		pFmoc-amino-l-phenylalanineb	p-Fmoc-amino-l-phenylalanine
43		p-Fmoc-amino-d-phenylalanine	p-Fmoc-amino-d-phenylalanine
44		O-Ethyl-l-tyrosine	O-Ethyl-l-tyrosine
45		O-Ethyl-d-tyrosine	O-Ethyl-d-tyrosine
46		l-Aspartic acid-β-fluorenylmethyl ester	p-Iodo-l-phenylalanine
47		d-Aspartic acid-β-fluorenylmethyl ester	p-Iodo-d-phenylalanine
48		p-Iodo-l-phenylalanine	O-Methyl-l-tyrosine
49		p-Iodo-d-phenylalanine	O-Methyl-d-tyrosine
50		O-Methyl-l-tyrosine
51		O-Methyl-d-tyrosine

^aSee reference 22. 

^bFmoc, 9-fluorenylmethoxycarbonyl.