Conversion of 3-amino-4-arylamino-1H-isochromen-1-ones to 1-arylisochromeno[3,4-d][1,2,3]triazol-5(1H)-ones : synthesis, spectroscopic characterization and the structures of four products and one ring-opened derivative

The authors thank 'Centro de Instrumentación Científico-Técnica of Universidad de Jaén' for data collection. The authors thank Universidad de Ciencias Aplicadas y Ambientales (UDCA), Universidad Nacional de Colombia, the Consejería de Innovación, Ciencia y Empresa (Junta de Andalucía, Spain) and the Universidad de Jaén for financial support.An efficient synthesis of 1-aryl­isochromeno[3,4-d][1,2,3]triazol-5(1H)-ones, involving the diazo­tization of 3-amino-4-aryl­amino-1H-isochromen-1-ones in weakly acidic solution, has been developed and the spectroscopic characterization and crystal structures of four examples are reported. The mol­ecules of 1-phenyl­isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H9N3O2, (I), are linked into sheets by a combination of C—H⋯N and C—H⋯O hydrogen bonds, while the structures of 1-(2-methyl­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C16H11N3O2, (II), and 1-(3-chloro­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, C15H8ClN3O2, (III), each contain just one hydrogen bond which links the mol­ecules into simple chains, which are further linked into sheets by π-stacking inter­actions in (II) but not in (III). In the structure of 1-(4-chloro­phen­yl)isochromeno[3,4-d][1,2,3]triazol-5(1H)-one, (IV), isomeric with (III), a combination of C—H⋯O and C—H⋯π(arene) hydrogen bonds links the mol­ecules into sheets. When com­pound (II) was exposed to a strong acid in methanol, qu­anti­tative conversion occurred to give the ring-opened transesterification product methyl 2-[4-hy­droxy-1-(2-methyl­phen­yl)-1H-1,2,3-triazol-5-yl]benzoate, C17H15N3O3, (V), where the mol­ecules are linked by paired O—H⋯O hydrogen bonds to form centrosymmetric dimers.Publisher PDFPeer reviewe

Synthesis of 5-(arylmethylideneamino)-4-(1<i>H</i>-benzo[<i>d</i>]imidazol-1-yl)pyrimidine hybrids:synthetic sequence and the molecular and supramolecular structures of two intermediates and three final products

Funding: Funding for this research was provided by: Spanish Ministerio de Ciencia, Innovacíon, y Universidades (R&D project No. RTI2018-098560-B-C22), co-financed by the FEDER funds of the European Union.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 R22(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 Z′ = 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...π(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 Z′ = 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.Publisher PDFPeer reviewe

A concise and efficient synthesis of amino-substituted (1H-benzo[d]imidazol-1-yl)pyrimidine hybrids: Synthetic sequence and the molecular and supramolecular structures of six examples

A concise and efficient synthesis of a series of amino-substituted benzimidazole-pyrimidine hybrids has been developed, starting from the readily available N 4-(2-aminophenyl)-6-methoxy-5-nitrosopyrimidine-2,4-diamine. In each of N 5-benzyl-6-methoxy-4-(2-phenyl-1H-benzo[d]imidazol-1-yl)pyrimidine-2,5-diamine, C25H22N6O, (I), 6-methoxy-N 5-(4-methoxybenzyl)-4-[2-(4-methoxyphenyl)-1H-benzo[d]imidazol-1-yl]pyrimidine-2,5-diamine, C27H26N6O3, (III), 6-methoxy-N 5-(4-nitrobenzyl)-4-[2-(4-nitrophenyl)-1H-benzo[d]imidazol-1-yl]pyrimidine-2,5-diamine, C25H20N8O5, (IV), the molecules are linked into three-dimensional framework structures, using different combinations of N-H⋯N, N-H⋯O, C-H⋯O, C-H⋯N and C-H⋯π hydrogen bonds in each case. Oxidative cleavage of 6-methoxy-N 5-(4-methylbenzyl)-4-[2-(4-methylphenyl)-1H-benzo[d]imidazol-1-yl]pyrimidine-2,5-diamine, (II), with diiodine gave 6-methoxy-4-[2-(4-methylphenyl)-1H-benzo[d]imidazol-1-yl]pyrimidine-2,5-diamine, which crystallized as a monohydrate, C19H18N6O·H2O, (V), and reaction of (V) with trifluoroacetic acid gave two isomeric products, namely N-{5-amino-6-methoxy-6-[2-(4-methylphenyl)-1H-benzo[d]imidazol-1-yl]pyrimidin-2-yl}-2,2,2-trifluoroacetamide, which crystallized as an ethyl acetate monosolvate, C21H17F3N6O2·C4H8O2, (VI), and N-{2-amino-6-methoxy-4-[2-(4-methylphenyl)-1H-benzo[d]imidazol-1-yl]pyrimidin-5-yl}-2,2,2-trifluoroacetamide, which crystallized as a methanol monosolvate, C21H17F3N6O2·CH4O, (VIIa). For each of (V), (VI) and (VIIa), the supramolecular assembly is two-dimensional, based on different combinations of O-H⋯N, N-H⋯O, N-H⋯N, C-H⋯O and C-H⋯π hydrogen bonds in each case. Comparisons are made with some related structures

A concise synthesis of a highly substituted 6-(1H-benzimidazol-1-yl)-5-nitrosopyrimidin-2- amine: Synthetic sequence and the molecular and supramolecular structures of one product and two intermediates

A concise and efficient synthesis of 6-benzimidazolyl-5-nitrosopyrimidines has been developed using Schiff base-type intermediates derived from N4-(2-aminophenyl)-6-methoxy-5-nitrosopyrimidine-2,4-diamine. 6-Methoxy-N4-{2-[(4-methylbenzylidene)amino]phenyl}-5-nitrosopyrimidine-2,4-diamine, (I), and N4-{2-[(ethoxymethylidene)amino]phenyl}-6-methoxy-5-nitrosopyrimidine-2,4-diamine, (III), both crystallize from dimethyl sulfoxide solution as the 1:1 solvates C19H18N6O2·C2H6OS, (Ia), and C14H16N6O3·C2H6OS, (IIIa), respectively. The interatomic distances in these intermediates indicate significant electronic polarization within the substituted pyrimidine system. In each of (Ia) and (IIIa), intermolecular N-H…O hydrogen bonds generate centrosymmetric four-molecule aggregates. Oxidative ring closure of intermediate (I), effected using ammonium hexanitratocerate(IV), produced 4-methoxy-6-[2-(4-methylphenyl-1H-benzimidazol-1-yl]-5-nitrosopyrimidin-2-amine, C19H16N6O2, (II) [Cobo et al. (2018). Private communication (CCDC 1830889). CCDC, Cambridge, England], where the extent of electronic polarization is much less than in (Ia) and (IIIa). A combination of N–H…N and C–H…O hydrogen bonds links the molecules of (II) into complex sheets