Different molecular conformations co-exist in each of three 2-aryl-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetam ides: hydrogen bonding in zero, one and two dimensions

作者：Narayana Badiadka; Yathirajan Hemmige S; Rathore Ravindranath S; Glidewell Christopher^*

来源：Acta Crystallographica Section C-Structural Chemistry, 2016, 72(9): 664-+.

DOI：10.1107/S2053229616012870

• synthesis
• molecular structure
• disorder
• molecular conformation
• hydrogen bonding
• crystal structure
• acetamide
• pyrazole

4-Antipyrine [4-amino-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one] and its derivatives exhibit a range of biological activities, including analgesic, antibacterial and anti-inflammatory, and new examples are always of potential interest and value. 2-(4-Chlorophenyl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) acetamide, C19H18ClN3O2, (I), crystallizes with Z' = 2 in the space group P (1) over bar, whereas its positional isomer 2-(2-chlorophenyl)-N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) acetamide, (II), crystallizes with Z' = 1 in the space group C2/c; the molecules of (II) are disordered over two sets of atomic sites having occupancies of 0.6020 (18) and 0.3980 (18). The two independent molecules of (I) adopt different molecular conformations, as do the two disorder components in (II), where the 2-chlorophenyl substituents adopt different orientations. The molecules of (I) are linked by a combination of N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds to form centrosymmetric four-molecule aggregates, while those of (II) are linked by the same types of hydrogen bonds forming sheets. The related compound N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-(3-methoxyphenyl) acetamide, C20H21N3O3, (III), is isomorphous with (I) but not strictly isostructural; again the two independent molecules adopt different molecular conformations, and the molecules are linked by N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds to form ribbons. Comparisons are made with some related structures, indicating that a hydrogen-bonded R-2(2)(10) ring is the common structural motif.

• 出版日期2016-9
• 单位北京理工大学