Synthesis and DFT analysis of non-covalent interactions in crystal structures of 6-R-2-alkoxy-, 2,3-di-, and 2,2,3-tri-tert-butylpyrrolo[1,2-b][1,2,4]triazines.

Novel 7-amino-3-tert-butyl-2-OR1-6-R2-pyrrolo[1,2-b][1,2,4]triazine-8-carbonitriles (R1 = CH2CO2Et, CH2Boc, Me, n-Bu; R2 = CO2Et, CO2n-Bu, CO2t-Bu, C6H4CO2i-Pr) have been synthesized and investigated by X-ray diffraction. Nucleophilic replacement of an alkoxy group with t-BuLi afforded sterically hindered tert-butyl 7-amino-2,3-di-tert-butyl- and 2,2,3-tri-tert-butyl-8-cyanopyrrolo[1,2-b][1,2,4]triazine-6-carboxylates. The lengths and bond angles as well as packing modes of molecules in crystals have been considered. The non-covalent interactions such as the changes in the H-bonding and close contacts were analyzed by DFT and the Hirshfeld surfaces and compared for different substituents. [ABSTRACT FROM AUTHOR]