Comparing the host behaviour of roof-shaped compounds trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid and its dimethyl ester in the presence of mixtures of xylene and ethylbenzene guests

CrystEngComm ◽  
2021 ◽  
Author(s):  
Benita Barton ◽  
Ulrich Senekal ◽  
Eric Cyriel Hosten
Keyword(s):  
Dicarboxylic Acid ◽  
Dimethyl Ester ◽  
Host Behaviour

Here we compare the host behaviour of two roof-shaped compounds, trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid H1 and its dimethyl ester, trans-dimethyl 9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylate H4, when presented with mixed xylene (o-Xy, m-Xy and p-Xy) and...

Natural Inhibitors of Germination and Growth, III New α-Pyrones from Seeds of Rosa canina

1985 ◽  
Vol 40 (7-8) ◽  
pp. 490-495 ◽  
Author(s):  
Edith Lohaus ◽  
Claudia Zenger ◽  
Wolfhart Rüdiger ◽  
Edmund Cmiel
Keyword(s):  
Nmr Spectroscopy ◽  
Dicarboxylic Acid ◽  
Parent Compound ◽  
Dimethyl Ester ◽  
Rosa Canina ◽  
Relationship Of ◽  
Germination And Growth ◽  
The Relationship ◽  
Natural Inhibitors ◽  
C Nmr

Abstract The new α-pyrone derivative II was isolated in crystalline form from extracts of dormant seeds of Rosa canina. It inhibits germination of seeds of Amaranthus caudatus completely, but reversibly, at conc. > 2.5 × 10-5 м . Its chemical structure was elucidated by mass spectrometry, 1H-and 13C-NMR spectroscopy to be 3-methyl-1-oxa-bicyclo (4,1,0) hept-5-en-2-one-4,6-dicarboxylic acid di­methylester (II). It is derived from 3-methyl-2H-pyran-2-one-4,6-dicarboxylic acid by cyclo-propanation with diazomethane. The parent compound which is a natural product of the seeds of Rosa canina was isolated as its dimethyl ester I the structure of which was elucidated by mass and NMR spectroscopy. I shows less inhibition of seed germination than II. The reference a-pyrones dimethyl-6-methyl-2H-pyran-2-one-3,5-dicarboxylate (III) , 3-methoxycarbonyl-5-methoxycar-bonylmethyl-6-methyl-2H-pyran-2-one (IV), and isodehydracetic acid methylester (V) did not show any inhibitory activity. The relationship of II with threo-dihydrohematinic acid (VII) is discussed.

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