Crystal structures of two anhydrous and one hydrated 7-(arylamino)-5-methyl-2-(trifluoromethyl)-[1,2,4]-triazolo-[1,5-a]pyrimidine derivatives

Abstract

Crystal structures of two anhydrous and one hydrated 7-(arylamino)-5-methyl-2-(trifluoromethyl)-[1,2,4]-triazolo-[1,5-a]pyrimidine derivatives Abstract: While in both 7-(arylamino)-5-methyl-2-(trifluoromethyl)-[1,2,4]-triazolo-[1,5-a]pyrimidines,1 [1a: aryl = 3,5dichlorophenyl; 1b: aryl = 2,4-dichlorophenyl), the strongest intermolecular interactions are N-H···N hydrogen bonds, different acceptor atoms are involved leading to different arrangement of molecules. In the case of 1a, N2A-H2A···N4B and N2B-H2B···N3A hydrogen bonds generate tetrameric units, composed of two molecules of each of the independent molecules, Mol A and Mol B. In the case of 1b, N2A-H2A···N4B and N2B-H2B···N4A hydrogen bonds generate C12 chains of alternate molecules A and B. As well as the strong N-H···N hydrogen bonds, there are also weaker π···π, C-X···π (X = Cl, F and H) and C-H···F interactions in 1a, and π···π, C-X···π (X = H and Cl) and C-H···X (X = F and N) interactions in 1b. In {[7-(4-chlorophenylamino)-5-methyl-2-(trifluoromethyl)-[1,2,4]-triazolo-[1,5-a]pyrimidine]. (H 2 O)}, [1c(H 2 O)], chains, C 2 2 (16) of alternate molecules of 1c and water are generated from combinations of OW-HW···N and N-H···OW intermolecular hydrogen bonds: also present are π(pyrimidine)···π(chlorophenyl), C-Cl··· π(triazole) and C-F··· π(pyrimidine) interactions. Comparisons with reported [1,2,4]-triazolo-[1,5-a]pyrimidine structures clearly show variations in the N-H···N hydrogen bonding patterns and the significant influence of the type and position of substituents on the supramolecular assemblies generated.

Synthesis of pyrimidine-6-carbonitriles, pyrimidin-5-ones, and tetrahydroquinoline-3-carbonitriles by new superb oxovanadium(V)-[5,10,15,20-tetrakis(pyridinium)-porphyrinato]-tetra(tricyanomethanide) catalyst via anomeric based oxidation

“…Triazolopyrimidines and tetrahydroquinolines were synthesized by using numerous approaches and catalysts such as thiamine hydrochloride (VB 1 ) 23 , Nafion-H 24 , phthalhydrazide-MCM-41 (P-MCM-41) 25 , boric acid under aqueous micellar medium 26 , [DABCO](SO 3 H) 2 Cl 2 and [DABCO](HSO 3 ) 2 (HSO 4 ) 2 27 , DBU 28 , microwave irradiation 29 , etc. [30][31][32][33][34][35][36][37][38][39] .…”