Table 1 Characterization of precursors tested using the agar-plate screening test

benzene derivatives

1,2-dihydroxybenzene

Cat

1-OH, 2-OH

548

285

aniline-2-sulfonic acid

A2SA

1-SO₃H, 2-NH₂

1013

-0.5

3-aminobenzenesulfonic acid

3ABS

1-SO₃H, 3-NH₂

968

5.4^a

3-amino-4-hydroxybenzenesulfonic acid

AHBS

1-SO₃H, 3-NH₂, 4-OH

518

-103

2,4-diaminobenzenesulfonic acid

2,4DABS

1-SO₃H, 2-NH₂, 4-NH₂

818

2,5-diaminobenzenesulfonic acid

2,5DABS

1-SO₃H, 2-NH₂, 5-NH₂

433

-356^a

3-amino-4-hydroxy-5-nitrobenzenesulfonic acid

AHNBS

1-SO₃H, 3-NH₂, 4-OH, 5-NO₂

339^a, 579

-92

5-sulfosalicylic acid hydrate

5SSA

1-COOH, 2-OH, 5-SO₃H

-

-

2-formylbenzenesulfonic acid sodium salt

2FBSA

1-SO₃Na, 2-CHO

-

-

4,5-dihydroxy-1,3-benzene-disulfonic acid

dHBdSA

1-SO₃Na, 3-SO₃Na, 4-OH, 5-OH

914^b

2-amino-3-hydroxypyridine

2A3HP

2-NH₂, 3-OH

647

144, 6.8

2-phenylphenol sodium salt tetrahydrate

2PP

2-ONa

790

naphtalene derivatives

2,7-dihydroxynaphtalene

DHN

2-OH, 7-OH

672

6-hydroxy-2-naphthalenesulfonic acid sodium salt

HNSA

2-SO₃Na, 6-OH

893

-144

4-amino-3-hydroxy-1-naphthalenesulfonic acid

4AHNS

1-SO₃Na, 3-OH, 4-NH₂

251

194,-1.4

6-amino-4-hydroxy-2-naphthalenesulfonic acid

6AHNS

2-SO₃Na, 4-OH, 6-NH₂

499

5-amino-1-naphthalenesulfonic acid

ANS

1-SO₃Na, 5-NH₂

680