(R)-2-phenylglycine (1.53 g, 10.2 mmol) was suspended in water (25 ml) and solid KOH was added until the solution cleared. The mixture was chilled in an ice/water bath and pyridine-2,6-dicarbonyl chloride (1.04 g, 5.1 mmol) in DCM (25 ml) was added. The mixture was stirred for 0.5 h in an ice/water bath, then for another 0.5 h at ambient temperature. The DCM layer was discarded. The aqueous layer was diluted with a further 100 ml of water and was acidified with formic acid (6 ml of conc. HCOOH in 30 ml of water) until turbidity developed. The solution was left to crystallise overnight. The product was filtered, washed successively with water, ethanol and diethyl ether and dried in vacuo. The filtrate was concentrated to obtain the second crop. The combined product was recrystallised from methanol/water. Yield 0.55 g (25%).

Elemental analysis found (calculated for C₂₃H₁₉N₃O₆∙3H₂O) %: C 56.91 (56.67), H 5.17 (5.17), N 8.55 (8.62).

¹H NMR (400 MHz, 298 K, CDCl₃) δ_H 5.71 (s, 2H, CH), 7.31-7.43 (m, 6H, Ph-H), 7.54 (d, 4H, J_HH=8Hz, Ph-H), 8.13 (t, 1H, J_HH=8Hz, pyr), 8.26 (d, 2H, J_HH=8Hz)

¹³C NMR (100 MHz, 298 K, CDCl₃) δ_C 58.2 (CH), 126.4, 128.7, 129.5, 130.0 (Ph), 138.0, 140.7, 150.0 (pyr), 165.3 (C=O), 173.6 (COOH)

MS (ESI⁺) m/z 456.12 [(M+Na]⁺), 889.24 ([2M+Na]⁺)

IR (cm^-1) ν 3391, 3036, 1725, 1669, 1513, 1442, 1389, 1319, 1253, 1182, 1095, 1074, 1030, 1001, 967, 843, 749, 724, 695, 663