Supporting Information

Laccase-induced C-N coupling of substituted p-hydroquinones with p-aminobenzoic acid in comparison with known chemical routes

Annett Mikolasch, Anastasia Matthies, Michael Lalk, and Frieder Schauer

List of contents

Structural data of biotransformation product 3a 2
Structural data of biotransformation product 3b1 4

Structural data of biotransformation product 3b2 6

Structural data of biotransformation product 3c 8
Structural data of biotransformation product 3d 10
Structural data of biotransformation product 3g1 12

Structural data of biotransformation product 3g2 14

Structural data of biotransformation product 3h 16
Structural data of compounds

2-[4´-(Carboxyphenyl)amino]-1,4-benzoquinone (3a). Red precipitate. Yield 3.9 mg (32.0 %). 1H NMR (methanol-d4) d 8.07 (d, 3J = 8.6 Hz, 2H, H3´, H5´), 7.41 (d, 3J = 8.5Hz, 2H, H2´, H6´), 6.80 (d, 3J=10.1Hz, 1H, H6), 6.73 (dd, 3J = 10.1 Hz, 4J = 2.5 Hz, 1H, H5), 6.22 (d, 4J = 2.5 Hz, 1H, H3). 13C NMR d 187.0 (C4), 182.5 (C1), 170.2 (C7´), 143.5 (C2), 142.0 (C1´), 138.5 (C5), 131.3 (C3´, C5´), 128.2 (C4´), 121.5 (C2´, C6´). HMBC correlations see table below. AP-ESI: neg. mode [M-H]- calculated 242.,04585 m/z; found 242.,046063 m/z.

1H / 1H 13C-correlations
6.22, d, H3 / C5, C1
6.73, dd, H5 / C1
6.80, d, H6 / C2, C4
7.41, d, H2´, H6´ / C2´, C6´, C3´, C5´, C4´
8.07, d, H3´, H5´ / C2´, C6´, C3´, C5´, C1´, C7´
3a / 2-[4´-(Carboxyphenyl)amino]-1,4-benzoquinone

1H NMR /
AP-ESI-MS
negativ mode /


5-[4´-(Carboxyphenyl)amino]-2-methyl-1,4-benzoquinone (3b1). Yield together with 3b2 5.0 mg (38.9 %).1H NMR (acetonitrile-d3) d 8.00 (d, 3J=8.6Hz, 2H, H3´, H5´), 7.38 (d, 3J = 8.6 Hz, 2H, H2´, H6´), 6.22 (s, 1H, H6), 6.18 (d(s), 4J= 2.8 Hz, 1H, H3), 2.06 (d, 4J = 2.8 Hz, 1H, H7), 2.04 (s, 2H, H7). 13C NMR d 185.0 (C1), 184.3 (C4), 167.1 (C7´), 143.9 (C1´), 143.0 (C5), 135.0 (C2) 132.0 (C3´, C5´), 124.6 (C2´, C6´) 103.0 (C3), 103.2 (C6), 15.2 (C7). HMBC correlations see table 2. AP-ESI: neg. mode [M-H]- calculated 256.,06155 m/z; found 256.,057324 m/z. AP-ESI: pos. mode [M+H]+ calculated 258.,07605 m/z; found 258.,07495 m/z.

1H / 1H 13C-correlations
2.04, s, H7 / C1
6.18, d(s), H3 / C1
6.22, s, H6 / C4
7.38, d, H2´, H6´ / C2´, C6´, C3´, C5´, C4´
8.00, d, H3´, H5´ / C2´, C6´, C3´, C5´, C1´, C7´
3b1 / 5-[4´-(Carboxyphenyl)amino]-2-methyl-1,4-benzoquinone

1H NMR
together with 3b2 /
AP-ESI-MS
negativ mode
together with 3b2 /
AP-ESI-MS
positiv mode
together with 3b2 /

6-[4´-(Carboxyphenyl)amino]-2-methyl-1,4-benzoquinone (3b2). Red precipitate. Yield together with 3b1 5.0 mg (38.9 %).1H NMR (acetonitrile-d3) d 8.00 (d, 3J=8.6Hz, 2H, H3´, H5´), 7.38 (d, 3J = 8.6 Hz, 2H, H2´, H6´), 6.62 (m, J = 1.9 Hz, J= 2.8 Hz, 1H, H3), 6.52 (m, J = 1.9 Hz, 1H, H5), 2.05 (d, J = 2.8 Hz, 1H, H7), 2.02 (d(s), J = 1.9 Hz, 2H, H7). 13C NMR d 187.7 (C1), 167.1 (C7´), 149.7 (C6), 143.9 (C1´), 132.0 (C3´, C5´), 130.7 (C2), 124.6 (C2´, C6´), 100.1 (C3), 100.4 (C5), 16.1 (C7). AP-ESI: neg. mode [M-H]- calculated 256.,06155 m/z; found 256.,057324 m/z. AP-ESI: pos. mode [M+H]+ calculated 258.,07605 m/z; found 258.,07495 m/z.

1H / 1H 13C-correlations
2.02, s, H7 / C1, C2, C6
6.52, m, H5 / C1
6.62, m, H3 / C1
7.38, d, H2´, H6´ / C2´, C6´, C3´, C5´, C4´
8.00, d, H3´, H5´ / C2´, C6´, C3´, C5´, C1´, C7´
3b2 / 6-[4´-(Carboxyphenyl)amino]-2-methyl-1,4-benzoquinone

1H NMR
together with 3b1 /
AP-ESI-MS
negativ mode
together with 3b1 /
AP-ESI-MS
positiv mode
together with 3b1 /


6-[4´-(Carboxyphenyl)amino]-2-tert-butyl-1,4-benzoquinone (3c). Black precipitate. Yield 1.0 mg (6.7%). 1H NMR (methanol-d4) d 8.04 (d, 3J = 8.4 Hz, 2H, H3´, H5´), 7.37 (d, 3J = 8.4Hz, 2H, H2´, H6´), 6.51 (d(s), 4J=1.8Hz, 1H, H3), 6.13 (d(s), 4J = 1.8 Hz, 1H, H5), 1.33 (s, 9H, H8). 13C NMR d 182.8 (C1), 168.9 (C7´), 152.4 (C2), 142.2 (C1´), 133.0 (C3), 130.6 (C3´, C5´), 128.3 (C4´), 121.4 (C2´, C6´), 99.7 (C5), 34.9 (C7), 27.9 (C8). HMBC correlations see table below. AP-ESI: neg. mode [M-H]- calculated 298.,10845 m/z; found 298.,105948 m/z.

1H / 1H 13C-correlations
1.33, s, H8 / C8, C7, C2, C3
6.13, d(s), H5 / C3, C1,
6.51, d(s), H3 / C7, C5, C1
7.37, d, H2´, H6´ / C2´, C6´, C4´
8.04, d, H3´, H5´ / C3´, C5´, C1´, C7´
3c / 6-[4´-(Carboxyphenyl)amino]-2-tert-butyl-1,4-benzoquinone

1H NMR /
AP-ESI-MS
negativ mode /


5-[4´-(Carboxyphenyl)amino]-2-methoxy-1,4-benzoquinone (3d). Red precipitate. Yield 7.1 mg (51.9%). 1H NMR (DMSO-d6) d 9.26 (s, 1H, NH), 7.94 (d, 3J = 8.6 Hz, 2H, H5´, H3´), 7.46 (d, 3J = 8.6 Hz, 2H, H6´, H2´), 6.08 (s, 1H, H3), 5.9 (s, 1H, H6), 3.81 (s, 3H, H7). 13C NMR d 183.3 (C4), 180.3 (C1), 167.1 (C7´), 161.2 (C2), 144.1 (C5), 142.5 (C1´), 131.3 (C3´, C5´), 127.2 (C4´), 122.7 (C2´, C6´), 104.8 (C3), 100.2 (C6). AP-ESI: neg. mode [M-H]- calculated 272.056398 m/z; found 272.054910 m/z.

1H-Signale / 1H 13C-Kopplungen
3.81, s, H7 / C2, C3
5.9, s, H6 / C5, C2, C4, C1
6.08, s, H3 / C4, C1, C2, C5,
7.46, d, H2´,H6´ / C2´, C6´, C3´, C5´, C4´
7.94, d, H3´, H5´ / C2´, C6´, C3´, C5´, C1´, C7´
3d / 5-[4´-(Carboxyphenyl)amino]-2-methoxy-1,4-benzoquinone

1H NMR /
AP-ESI-MS
negativ mode /

3-[4´-(Carboxyphenyl)amino]-2-chloro-1,4-benzoquinone (3g1). Black precipitate. Yield 5.3 mg (38.17%). 1H NMR (methanol-d4) d 7.96 (d, 3J= 8.4 Hz, 2H, H3´, H5´), 7.09 (d, 3J = 8.4 Hz, 2H, H2´, H6´), 6.95 (d, 3J = 10.1 Hz, 1H, H6), 6.85 (d, 3J= 10.1 Hz, 1H, H5). 13C NMR d  181.9 (C4), 179.8 (C1), 172.1 (C7´), 142.6 (C1´), 140.9 (C3), 137.5 (C6), 133.3 (C5), 129.5 (C3´, C5´), 127.2 (C4´), 122.3 (C2´, C6´), 113.8 (C2). HMBC correlations see table 2. AP-ESI: neg. mode [M-H]- calculated 276.,006910 m/z; found 276.,015621 m/z.

1H / 1H 13C-Correlations
6.85, d, H5 / C1, C3
6.90, d, H6 / C2, C4
7.09, d, H2´, H6´ / C2´, C6´, C3´, C5´, C4´
7.96, d, H3´, H5´ / C2´, C6´, C3´, C5´, C1´, C7´
3g1 / 3-[4´-(Carboxyphenyl)amino]-2-chloro-1,4-benzoquinone

1H NMR /
AP-ESI-MS
negativ mode /


5-[4´-(Carboxyphenyl)amino]-2-chloro-1,4-benzoquinone (3g2). Black precipitate. Yield 2.1 mg (15.1 %).1H NMR (methanol-d4) d 8.14 (d, 3J = 8.4 Hz, 2H, H3´, H5´), 7.42 (d, 3J = 8.4 Hz, 2H, H2´, H6´), 7.09 (s, 1H, H3), 6.29 (s, 1H, H6). 13C NMR d 181.3 (C4), 178.5 (C1), 169.5 (C7´), 146.1 (C2), 145.2 (C5), 141.5 (C1´) 131.2 (C3´, C5´), 130.8 (C3), 128.3 (C4´), 122.5 (C2´, C-6´), 100.1 (C6). HMBC correlations see table 2. AP-ESI: neg. mode [M-H]- calculated 276.,006910 m/z; found 276.,010965 m/z.

1H / 1H 13C-Correlations
6.29, s, H6 / C2, C4
7.09, s, H3 / C1, C5,
7.42, d, H2´, H6´ / C2´, C6´, C3´, C5´, C4´
8.14, d, H3´, H5´ / C2´, C6´, C3´, C5´, C1´, C7´
3g2 / 5-[4´-(Carboxyphenyl)amino]-2-chloro-1,4-benzoquinone

1H NMR /
AP-ESI-MS
negativ mode /


3-[4´-(Carboxyphenyl)amino]-2,6-dichloro-1,4-benzoquinone (3h). Black-violett precipitate. Yield 6.0 mg (38.45 %). 1H NMR (acetonitrile-d3) d 7.98 (s, 1H, NH), 7.95 (d, 3J = 8.6 Hz, 2H, H3´, H5´), 7.12 (d, 3J = 8.6 Hz, 2H, H2´, H6´), 7.09 (s, 1H, H5). 13C NMR d 180.9, 177.2, 173.6, 146.4, 143.2, 141.8, 131.8, 130.8, 127.1, 124.0, 114.5. AP-ESI: neg. mode [M-H]- calculated 309.9685 m/z; found 309.965546 m/z. AP-ESI: pos. mode [M+H]+ calculated 311.98245 m/z; found 311.982417 m/z; [M+Na]+ calculated 333.964431 m/z; found 333.965302 m/z.

3h / 3-[4´-(Carboxyphenyl)amino]-2,6-dichloro-1,4-benzoquinone
AP-ESI-MS
negativ mode /
AP-ESI-MS
positiv mode /

17