Li C, Weaver MJ, Campbell MJ, Natale NR. Syntheses and crystal structures of a nitro–anthracene–isoxazole and its oxidation product.
Acta Crystallogr E Crystallogr Commun 2022;
78:703-708. [PMID:
35855371 PMCID:
PMC9260358 DOI:
10.1107/s2056989022005710]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 05/25/2022] [Indexed: 12/04/2022]
Abstract
The title compounds arose as unexpected by-products of an iodination reaction: in each case the fused-ring and isoxazole planes are almost perpendicular to each other.
The syntheses and structures of an unexpected by-product from an iodination reaction, namely, ethyl 5-methyl-3-(10-nitroanthracen-9-yl)isoxazole-4-carboxylate, C21H16N2O5, (I), and its oxidation product, ethyl 3-(9-hydroxy-10-oxo-9,10-dihydroanthracen-9-yl)-5-methylisoxazole-4-carboxylate, C21H17NO5 (V) are described. Compound (I) crystallizes with two molecules in the asymmetric unit in which the dihedral angles between the anthracene fused-ring systems and isoxazole ring mean planes are 88.67 (16) and 85.64 (16)°; both molecules feature a disordered nitro group. In (V), which crystallizes with one molecule in the asymmetric unit, the equivalent dihedral angle between the almost planar anthrone ring system (r.m.s. deviation = 0.029 Å) and the pendant isoxazole ring is 89.65 (5)°. In the crystal of (I), the molecules are linked by weak C—H⋯O interactions into a three-dimensional network and in the extended structure of (V), inversion dimers linked by pairwise O—H⋯O hydrogen bonds generate R22(14) loops.
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