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Polymorphism of N-(1-benzotriazolylcarbonyl)-glycine

As a part of an ongoing study on small peptides, we used N-(1-benzotriazolylcarbonyl)-glycine (N-BtCO-Gly-OH) as a valuable building block.[1]- [3] It is the only one, from the series of such N-BtCO-amino acids and other N-(1-azolylcarbonyl)-amino acids investigated, that gave hydrated product by crystallization from aqueous solvents. Performed structural studies (IR, XRPD, DSC) showed that anhydrous N-BtCO-Gly-OH was obtained in two polymorphic forms: microcrystalline needles obtained by crystallization from toluene (form A) and plates obtained by saturation of N-BtCO-Gly-OH acetonitrile solution with water (form B). Single-crystal x-ray diffraction of later showed strong intra- and intermolecular hydrogen bonding. C9H8N4O3, Mr = 220.19, Monoclinic P21/n, Z = 4 × 2, a = 7.456(2), b = 15.860(2), c = 16.625(3)Å ; , beta=95.31(2)°, V = 1957.5(7)Å ; ; 3, l(Mo Ka)=0.7107 Å ; , RF = 0.0526, wRF2 = 0.1241 and S = 1.008 for 297 parameters and 3661 observed reflection with I > 2s(I). However, crystallization of N-BtCO-Gly-OH from acetone-water leads to the formation of monohydrated product (form H), which losses water on heating at 86-115 º ; C. Form H crystallize in orthorhombic space group P212121 with the unit cell parameters a = 4.823(5) Å ; , b= 14.0493(2) Å ; , c = 15.2980(8) Å ; , characterized by strong intra- and intermolecular hydrogen bonding and IR bands n (-CO-) at 1711 and n(NH) at 3357 cm-1 and two sharp n(OH) bands at 3573 and 3455 cm-1, respectively. [1] I. Butula, B. Zorc, V. Vela, Croat. Chem. Acta 54 (1981) 435-440. [2] I. Butula, B. Zorc, M. Ljubić, Synthesis, 1983, 327-329. [3] I. Kalčić, M. Zovko, M. Jadrijević-Mladar Takač, B. Zorc, I. Butula, Croat. Chem. Acta, 76 (2003), 217-228.

polymorphism; N-(1-benzotriazolylcarbonyl)-glycine; solvates

doi: 10.1107/S0108767304095819