title: Five N'-benzylidene-N-methylpyrazine-2-carbohydrazides.
abstract: The compounds N'-benzylidene-N-methylpyrazine-2-carbohydrazide, C13H12N4O, (IIa), N'-(2-methoxybenzylidene)-N-methylpyrazine-2-carbohydrazide, C14H14N4O2, (IIb), N'-(4-cyanobenzylidene)-N-methylpyrazine-2-carbohydrazide dihydrate, C14H11N5O·2H2O, (IIc), N-methyl-N'-(2-nitrobenzylidene)pyrazine-2-carbohydrazide, C13H11N5O3, (IId), and N-methyl-N'-(4-nitrobenzylidene)pyrazine-2-carbohydrazide, C13H11N5O3, (IIe), have dihedral angles between the pyrazine rings and the benzene rings in the range 55-78°. These methylated pyrazine-2-carbohydrazides have supramolecular structures which are formed by weak C-H···O/N hydrogen bonds, with the exception of (IIc) which is hydrated. There are π-π stacking interactions in all five compounds. Three of these structures are compared with their nonmethylated counterparts, which have dihedral angles between the pyrazine rings and the benzene rings in the range 0-6°.
authors: REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, P-4169-007 Porto, Portugal.
authors: Ligia R
authors: LR
authors: Gomes
authors: John Nicolson
authors: JN
authors: Low
authors: Ana S M C
authors: AS
authors: Rodrigues
authors: James L
authors: JL
authors: Wardell
authors: Camillo H da Silva
authors: CH
authors: Lima
authors: Marcus V N
authors: MV
authors: de Souza
mesh_terms: D001597:Benzylidene Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008958:Models, Molecular; D011719:Pyrazines / Q000737:chemistry*
chemical_list: D001597:Benzylidene Compounds; D011719:Pyrazines