*2.3. Cocrystal Synthesis*

*(pic)-(D-H2ma)* (**1**). DL-mandelic acid (0.152 g, 1.0 mmol) and picolinamide (0.122 g, 1.0 mmol). Ethyl acetate (3 mL). Colorless crystals after one day. M.p. (◦C): 88–92. Elemental analysis: Found: C, 59.72; H, 5.10; N, 10.27. Calculated (%) for C14H14N2O4: C, 61.31; H, 5.45; N, 10.21. IR (νmax/cm–1): 3471–3435 ν(NH2), ν(OH), 3282 ν(NH2), 1695–1633 ν(C=O), 1589, 1570, 1418 ν(CN), 1293, 1269, 1187, 1107, 1066–1012 ν(C-O), 995, 755, 725, 697, 645–616 α(CCC), 600. 1H NMR (DMSO-d6, ppm): 12.50 (br, 1H, COOH), 8.62 (m, 1H, py), 8.12 (s, 1H, NH2), 8.05–7.97(m, 2H, py), 7.64 (s, 1H, NH2), 7.65–7.58 (m, 5H, ring), 5.86 (s, 1H, CH), 5.02 (s, 1H, OH). 13C NMR (DMSO-d6, ppm): 174.3 (C1), 166.3 (C11), 150.4 (C12), 140.4 (C3), 137.8 (C14), 128.3 (C3, C7), 127.8 (C6), 126.8 (C4, C8), 126.6 (C15), 122.0 (C13), 72.4 (C2).

*(inam)-(L-H2ma)* (**3**). DL-mandelic acid (0.152 g, 1.0 mmol) and isonicotinamide (0.122 g, 1.0 mmol). Ethyl acetate (11 mL). Colorless crystals after one day. M.p. (◦C): 107– 114. Elemental analysis: Found: C, 59.89; H, 4.85; N, 10.55. Calculated (%) for C14H16N2O4: C, 61.31; H, 5.45; N, 10.21. IR (νmax/cm–1): 3424–3379 ν(NH2), ν(OH), 3162 ν(NH2), 1729, 1694–1604 ν(C=O), 1555, 1420–1407 ν(CN), 1303, 1227, 1188, 1065–1018 ν(C-O), 756, 737, 695, 647 α(CCC), 606. 1H NMR (DMSO-d6, ppm): 12.53 (br, 1H, COOH), 8.70–8.60(m, 2H, py), 8.22 (s, 1H, NH2), 7.75–7.70 (m, 3H, py) 7.40 (s, 1H, NH2), 7.37–7.23 (m, 5H, ring), 5.82 (s, 1H, CH), 4.99 (s, 1H, OH). 13C NMR (DMSO-d6, ppm): 174.3 (C1), 166.5 (C11), 150.4 (C14, C16), 140.3 (C12), 128.2 (C3, C7), 127.7 (C6), 126.7 (C4, C8), 121.5 (C13, C17), 72.4 (C2).
