*3.4. Isolation and Purification of the Derivatives*

The extracts from the culture broths of *C. elegans* or *A. brasiliensis* (scale-up biotransformations) with coumarins **4** and **7** were submitted to an isolation procedure (as described in Section 3.1) to yield the derivatives **C1** and **C2**, respectively.

3 ,7-dihydroxy-2,3-dihydrocyclopenta[*c*]chromen-4(1*H*)-one (**C1**): 3.6 mg (9.0% yield) brown powder; [α] 20D <sup>=</sup>−16◦ (0.34; CH3OH); 1H NMR (600 MHz, CD3OD) 7.44 (d, *<sup>J</sup>* <sup>=</sup> 8.4 Hz, 1H, H-5), 6.77 (dd, *J* = 8.4 and 2.2 Hz, 1H, H-6), 6.68 (d, *J* = 2.2 Hz, 1H, H-8), 5.20–5.22 (ddd, *J* = 6.9, 2.2, and 1.4 Hz, 1H, H-9), 3.17–3.23 (dddd, *J* = 18.0, 8.0, 6.9, and 1.4 Hz, 1H, H-11a), 2.95–3.00 (ddd, *J* = 18.0, 9.1, and 3.3 Hz, 1H, H-11b), 2.42–2.48 (dddd, *J* = 13.5, 9.1, 6.9, and 6.9 Hz, 1H, H-10a), 2.00–2.05 (dddd, *J* = 13.5, 8.0, 3.3, and 2.2 Hz, 1H, H-10b); 13C NMR (150 MHz, CD3OD) 163.1 (C-2), 162.2 (C-7), 161.3 (C-4), 158.2 (C-8a), 127.8 (C-5 and C-3), 115.5 (C-6), 103.8 (C-4a and C-8), 75.1 (C-9), 34.2 (C-10), 30.3 (C-11). HRESIMS *m*/*z* 217.0507 [M -H]<sup>−</sup> (calcd for [M −H]<sup>−</sup> 217.0501).

2-(7-hydroxy-2-oxo-2*H*-chromen-4-yl) acetic acid (**C2**): 13.0 mg (35.0% yield) brown powder; 1H NMR (400 MHz, DMSO-d6) 12.75 (br s, 1H, COOH), 10.57 (s, 1H, OH-7), 7.54 (d, *J* = 8.7 Hz, 1H, H-5), 6.82 (dd, *J* = 8.7 and 2.3 Hz, 1H, H-6), 6.74 (d, *J* = 2.3 Hz, 1H, H-8), 6.23 (s, 1H, H-3), 3.83 (s, 2H, H-9).

**Supplementary Materials:** The following are available online, Figure S1: 1H NMR spectrum of compound **C1** (600 MHz, CD3OD); Figure S2: 13C NMR spectrum of compound **C1** (150 MHz, CD3OD); Figure S3: 1H-13C HSQC 2D NMR correlation spectroscopy of compound **C1** (600 MHz/150 MHz, CD3OD); Figure S4: 1H-13C HMBC 2D NMR correlation spectroscopy of compound **C1** (600 MHz/150 MHz, CD3OD); Figure S5: 1H-1H COSY 2D NMR correlation spectroscopy of compound **C1** (600 MHz, CD3OD); Figure S6: HRESIMS spectrum of compound **C1** (negative ion mode); Figure S7: 1H NMR spectrum of compound **C2** (400 MHz, DMSO-d6).

**Author Contributions:** J.S.d.N. and V.H.P.d.S. carried out the biotransformation experiments, W.E.R.N. and S.C. synthetized the coumarins, J.A. acquired and interpreted the NMR and MS spectra, and E.d.O.S. designed the experiments, interpreted the NMR spectra, and wrote the paper.

**Funding:** The authors are grateful to the "Bahia Research Foundation" (FAPESB), "Conselho Nacional de Desenvolvimento Científico e Tecnológico" (CNPq), and "Coordenacão de Aperfeiçoamento de Pessoal de Nível Superior" (CAPES, Finance Code 001).

**Acknowledgments:** E.O.S. thanks Niege Araçari Jacometti Cardoso Furtado for kindly giving the fungal strains.

**Conflicts of Interest:** The authors declare no conflicts of interest.
