Syntheses and Crystal Structures of Two Unsymmetrical 1,2,4,5-tetrazine Derivatives

Two unsymmetrical 1,2,4,5-tetrazine derivatives, (6-(3,5-dimethyl- 1H -pyrazol-1-yl)-1,2,4,5-tetrazin-3-ylamino)methanol (C 9 H 13 N 7 O, 3 ) and 4-(6-(3,5-dimethyl- 1H -pyrazol-1-yl)-1,2,4,5-tetrazin-3-yl) morpholine (C 11 H 15 N 7 O, 4 ), were synthesized from 3,6-bis(3,5-dimethyl- 1H -pyrazol-1-yl)-1,2,4,5-tetrazine and the corresponding aliphatic amine (2-aminoethanol and morpholine, respectively), there structures were confirmed by single-crystal X-ray diffraction methods. Both molecules have very similar bond length and angle patterns, The crystal structures show that compound 3 is stabilized by intermolecular O–H–N, N–H–O hydrogen bonds and π–π interactions, while compound 4 is stabilized by π–π interactions. The structure analyses establish that compound 3 belongs to the monoclinic system, space group P 2(1)/ c , with crystal data a = 6.979(2) Å, b = 9.563(3) Å, c = 16.542(5) Å, V = 1084.4(5) Å 3 , Z = 4, F (000) = 496, R 1 = 0.0488, wR 2 = 0.1063. Compound 4 belongs to the orthorhombic system, space group P 2(1)2(1)2(1), with crystal data a = 6.544(14) Å, b = 12.085(3) Å, c = 15.753(4) Å, V = 1245.7(5) Å 3 , Z = 4, F (000) = 552, R 1 = 0.0403, wR 2 = 0.0913. Graphical Abstract