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)acetamides: hydrogen bonding in zero, one and two dimensions

Narayana, B. and Yathirajan, H. S. and Rathore, Ravindranath S. and Glidewell, Christopher (2016) 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)acetamides: hydrogen bonding in zero, one and two dimensions. Acta Crystallographica Section C, 72 (9). pp. 664-669. ISSN 2053-2296

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Abstract

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[\overline{1}], 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⋯O and C—H⋯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⋯O and C—H⋯O hydrogen bonds to form ribbons. Comparisons are made with some related structures, indicating that a hydrogen-bonded R22(10) ring is the common structural motif.

Item Type:	Article
Uncontrolled Keywords:	synthesis, molecular structure, disorder, molecular conformation, hydrogen bonding, crystal structure, acetamide, pyrazole
Subjects:	C Chemical Science > Chemistry
Divisions:	Department of > Chemistry
Depositing User:	C Swapna Library Assistant
Date Deposited:	13 Nov 2019 05:22
Last Modified:	13 Nov 2019 05:22
URI:	http://eprints.uni-mysore.ac.in/id/eprint/9994

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