Synthesis of 5-(arylmethylideneamino)-4-(1Hbenzo[ d]imidazol-1-yl)pyrimidine hybrids: synthetic sequence and the molecular and supramolecular structures of two intermediates and three final products
Fecha de publicación: 25/04/2023

A concise and versatile synthesis of 5-(arylmethylideneamino)-4-(1H-benzo[d]-imidazol-1-yl)pyrimidines has been developed, starting from 4-(1H-benzo[d]-imidazol-1-yl)pyrimidines, and we report here the synthesis and spectroscopic and structural characterization of three such products, along with those of two intermediates in the reaction pathway. The intermediates 4-[2-(4-chlorophenyl)-1H-benzo[d]imidazol-1-yl]-6-methoxypyrimidine-2,5-diamine, (II), and 4-[2-(4-bromophenyl)-1H-benzo[d]imidazol-1-yl]-6-methoxypyrimidine-2,5-diamine, (III), crystallize as the isostructural monohydrates C18H15ClN5O·H2O and C18H15BrN5O·H2O, respectively, in which the components are linked into complex sheets by O—H…N and N—H…O hydrogen bonds. In the product (E)-4-methoxy-5-[(4-nitrobenzylidene)amino]-6-[2-(4-nitrophenyl)-1H-benzo[d]-imidazol-1-yl]pyrimidin-2-amine, which crystallizes as a 1:1 solvate with dimethyl sulfoxide, C25H18N8O5·C2H6OS, (IV), inversion-related pairs of the pyrimidine
component are linked by N—H…N hydrogen bonds to form cyclic centrosymmetric R2 2(8) dimers to which pairs of solvent molecules are linked by N—H…O hydrogen bonds. (E)-4-Methoxy-5-[(4-methylbenzylidene)amino]-6-[2-(4-methylphenyl)-1H-benzo[d]imidazol-1-yl]pyrimidin-2-amine, C27H24N6O, (V), crystallizes with Z0 = 2 and the molecules are linked into a three-dimensional framework structure by a combination of N—H…N, C—H…N and C—H…(arene) hydrogen bonds. The analogous product (E)-4-methoxy-5- [(4-chlorobenzylidene)amino]-6-[2-(4-methylphenyl)-1H-benzo[d]imidazol-1-yl]pyrimidin-2-amine, C26H21ClN6O, (VI), crystallizes from dimethyl sulfoxide in two forms: one, denoted (VIa), is isostructural with (V), and the other, denoted (VIb), crystallizes with Z0 = 1, but as an unknown solvate in which the pyrimidine molecules are linked by N—H…N hydrogen bonds to form a ribbon containing two types of centrosymmetric ring.