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3‐Substituted Sydnone Derivatives. Structures of 3‐Cyclohexylsydnone and of Two Forms of 3‐(3‐Pyridyl)sydnone
Author(s) -
Rychlewska Urszula,
Hodgson Derek J.,
Yeh Andrew,
Tien HsienJu
Publication year - 1991
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.199100078
Subject(s) - sydnone , monoclinic crystal system , chemistry , crystallography , molecule , bond length , group (periodic table) , crystal structure , stereochemistry , organic chemistry , ring (chemistry)
The crystal and molecular structures of three sydnone derivatives are reported. The compound 3‐cyclohexylsydnone crystallizes in space group C2/c of the monoclinic system with sixteen molecules in a cell of dimensions a = 19.326 (3), b = 9.471 (2), c = 20.005 (4)Å, β = 106.85(1)°. The structure has been refined to a final value of 0.0581 for the conventional R‐factor based on 2222 independent observed intensities. Form I of 3‐(3‐pyridyl)sydnone crystallizes in space group P2/n of the monoclinic system with eight molecules in a cell of dimensions a = 7.317(2), b = 9.283 (2), c = 20.891 (6) Å, β = 99.61(2)°. The structure has been refined to a final value of 0.0514 for the conventional R‐factor based on 1208 independent observed intensities. Form II of 3‐(3‐pyridyl)sydnone crystallizes in space group P2 1 /c of the monoclinic system with eight molecules in a cell of dimensions a=9.073 (2), b = 22.267 (5). c = 7.494(2)Å, β = 112.15 (2)°. The structure has been refined to a final value of 0.0462 for the conventional R‐factor based on 1330 independent observed intensities. Each of the three structures contains two crystallographically independent molecules in the cell. In the case of 3‐cyclohexylsydnone, one of the independent molecules exhibits disorder around the exocyclic bond at N(3). A comparison of bond lengths indicates that the (electron donating) cyclohexyl group brings about enhanced electron density in the N(3)‐C(4) bond, and possibly in the N(3)‐N(2) bond. All three structures studied here exhibit intermolecular hydrogen bonding involving C(4)‐H(4)…O(6) interactions. Although there are no stacking interactions in the cyclohexyl derivative, there is evidence for such interactions in the 3‐pyridyl derivatives.