Published June 1974 | Version Published
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Avicennin: hypersymmetry in space group P1

Abstract

Triclinic, 1i, a= 11.209 (1), b= 10.196 (2), c=9.634 (2) Å, α = 82.76 (2), β = 109.43 (1), γ = 123.61 (1)°, Z=2; C_(20)H_(20)O_4, F. W. 324.38, D_m = 1.25, D_x = 1.249 g cm^(-3). The molecular structure is found to be based on a coumarin system fused at the 5,6 positions to an α-pyran ring. The structure was solved by Patterson methods; failure of direct phasing methods can be traced to an 'aberrant phase relationship' due to the hypersymmetry of the molecule, as discussed by Thiessen & Busing [Abs. Amer. Cryst. Assoc. (1973). Storrs, Connecticut, paper N-12, p. 183].

Additional Information

© 1974 International Union of Crystallography. (Received 30 January 1974; accepted 21 February 1974) This investigation was supported in part by Public Health Service Research Grant No. GM 16966, from the National Institute of General Medical Sciences, National Institutes of Health. We are grateful to Dr David Duchamp for calculating the molecular transform, to Miss Lillian Casler for preparing most of the figures, and to Miss Allison Kimball for preparing the manuscript.

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75219
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CaltechAUTHORS:20170317-151311629

Funding

NIH
GM 16966

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2017-03-17
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2021-11-15
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Arthur Amos Noyes Laboratory of Chemical Physics
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4820