Abstract: Agnotobenzaldehyde was first reported by Dr. Eugen Bamberger in 1906, from a Zn-promoted reduction of 2-nitrobenzaldehyde. He determined the empirical formula to be C14H12N2O5. Subsequent work determined the chemical structure of the solution form by IR and NMR analysis, but the structure of the crystal form remained inconclusive. In the present work, the structure of crystalline agnotobenzaldehyde has been found to be rac-(3R)-1-[(S)-hydroxy(2-nitrophenyl)methyl]-1,3-dihydro-2,1-benzisoxazol-3-ol. Crystals are orthorhombic with the Pbca space group. At 173(2) K, a = 13.8066(14), b = 8.4412(9), c = 22.832(2) Å, and V = 2660.9(5) Å3 with Z = 8. Poly(O–H⋯) C4 4(8) chains of alternating intra- and inter-molecular hydrogen bonds form along the b axis. These chains probably affect the regio- and diastereo-specificity of cyclization. Graphical Abstract: The crystalline form of agnotobenzaldehyde has a different molecular structure than the solution form, and features hydrogen bond chains that probably control the stereo- and regio-specificity of the hydroxyl and isoxazole moieties. [Figure not available: see fulltext.].
Bibliographical noteFunding Information:
The authors thank Abigail E. Zabronsky and Christopher D. Brown for assistance with the interpretation of literature items printed in German. The authors also thank Victor G. Young, Jr. (X-Ray Crystallographic Laboratory, University of Minnesota) for assistance with the refinement of crystallographic data, and the Wayland E. Noland Research Fellowship Fund at the University of Minnesota Foundation for generous financial support of this project. This work is taken in large part from the MS thesis of GCG .
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- Nitrogen heterocycles