ISSN:
1572-8854
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geosciences
,
Physics
Notes:
Abstract α-Parabutylchloral (2,4,6-tris(1′,1′,2′-trichloropropyl)-1,3,5-trioxane, C12H15Cl9O3) crystallizes in the orthorhombic space groupP212121 (No. 19) witha=12.165(6),b=9.964(5),c=17.433(9) Å,Z=4. The finalR value is 0.043 for 1667 observed reflections.β-Parabutylchloral crystallizes in the orthorhombic space groupPna21 (No. 33), witha=12.387(6),b=10.488(5),c=16.605(8) Å,Z=4. The finalR value is 0.047 for 1417 observed reflections. Unlike the geometric isomersα- andβ-parachloral (CCl3CHO)3 which exist in boat andcis,cis-chair conformations, theα- andβ-forms of parabutylchloral (CH3CHClCCl2CHO)3 are now shown by X-ray crystallography not to be geometric isomers. Both forms exist incis,cis-chair conformations and the isomerism arises from the chirality of the side chains at theβ-carbon atoms. In theα-form only two of the side chains have the same chirality, but in theβ-form the chirality at all theβ-carbon atoms is the same. The X-ray results are supplemented by1H and13C nuclear magnetic resonance spectroscopy and by mass spectrometry.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01160726
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