Abstract
Six 1-halobenzoyl-4-(2-meth-oxy-phen-yl)piperazines have been prepared using carbodi-imide-mediated coupling reactions between halo-benzoic acids and N-(2-meth-oxy-phen-yl)piperazine. The mol-ecules of 1-(4-fluoro-benzo-yl)-4-(2-meth-oxy-phen-yl)piperazine, C18H19FN2O2 (I), are linked into a chain of rings by a combination of C-H⋯O and C-H⋯π(arene) hydrogen bonds. 1-(4-Chloro-benzo-yl)-4-(2-meth-oxy-phen-yl)piperazine, C18H19ClN2O2 (II), crystallizes in the space group Pca21 with Z' = 4 and it exhibits both pseudosymmetry and inversion twinning: a combination of six C-H⋯O and two C-H⋯π(arene) hydrogen bonds generate a three-dimensional assembly. In 1-(4-bromo-benzo-yl)-4-(2-meth-oxy-phen-yl)piperazine, C18H19BrN2O2 (III), which also crystallizes in space group Pca21 but with Z' = 2, the bromo-benzoyl unit in one of the mol-ecules is disordered. Pseudosymmetry and inversion twinning are again present, and a combination of three C-H⋯O and one C-H⋯π(arene) hydrogen bonds generate a two-dimensional assembly. A single C-H⋯O hydrogen bond links the mol-ecules of 1-(4-iodo-benzo-yl)-4-(2-meth-oxy-phen-yl)piperazine, C18H19IN2O2 (IV), into simple chains but in the isomeric 3-iodo-benzoyl analogue (V), which crystallizes in space group P212121 with Z' = 2, a two-dimensional assembly is generated by a combination of four C-H⋯O and two C-H⋯π(arene) hydrogen bonds; pseudosymmetry and inversion twinning are again present. A single C-H⋯O hydrogen bond links the mol-ecules of 1-(2-fluoro-benzo-yl)-4-(2-meth-oxy-phen-yl)piperazine, C18H19FN2O2 (VI), into simple chains. Comparisons are made with the structures of some related compounds.
Highlights
Six 1-halobenzoyl-4-(2-methoxyphenyl)piperazines have been prepared using carbodiimide-mediated coupling reactions between halobenzoic acids and N-(2methoxyphenyl)piperazine
A single C—HÁ Á ÁO hydrogen bond links the molecules of 1-(4-iodobenzoyl)-4-(2-methoxyphenyl)piperazine, C18H19IN2O2 (IV), into simple chains but in the isomeric 3-iodobenzoyl analogue (V), which crystallizes in space group P212121 with Z0 = 2, a two-dimensional assembly is generated by a combination of four C— HÁ Á ÁO and two C—HÁ Á Á(arene) hydrogen bonds; pseudosymmetry and inversion twinning are again present
A single C—HÁ Á ÁO hydrogen bond links the molecules of 1-(2-fluorobenzoyl)-4-(2-methoxyphenyl)piperazine, C18H19FN2O2 (VI), into simple chains
Summary
N-(2-Methoxyphenyl)piperazine (2-MeOPP) has been used as a building block in the synthesis of both 5-HT1A receptor ligands (Orjales et al, 1995) and dopamine D2 and D3 ligands (Hackling et al, 2003), and as a building block for the synthesis of derivatives exhibiting antidepressant-like activity (Waszkielewicz et al, 2015). We have recently reported the structures of a range of salts derived from 2-MeOPP (Harish Chinthal et al, 2020a) and here we report the syntheses and structures of six 1-haloaroyl-4-(2-methoxyphenyl)piperazines, (I)–(VI). The work reported here represents a continuation of an earlier study on the isomeric N-(4-methoxyphenyl)piperazine (4-MeOPP) (Kiran Kumar et al, 2020) and a range of salts and N-aroyl derivatives derived from 4-MeOPP Compounds (I)– (VI) were prepared using carbodiimide-mediated reactions between N-(2-methoxyphenyl)piperazine and a halogensubstituted benzoic acid
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