ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

Structure of two 1,3-dioxane derivatives from 4′, 5′-dimethylfurocoumarins: 4a, 11a-dihydro-4a, 11a-dimethyl-8H-pyrano[3′,2′∶5,6]benzofuro[3,2-e]-1, 3-dioxan-8-one and 7a,11a-dihydro-7a,11a-dimethyl-2H-pyrano[2′, 3′∶4,5]benzofuro[3,2-d] (1,3) dioxan-2-one (1987)

Guiotto, A. ; Bandoli, G. ; Manzini, P. ; [et al.]

Springer

Journal of chemical crystallography 17 (1987), S. 349-364

add to mindlist on the mindlist

Details

ISSN: 1572-8854

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Notes: Abstract Treatment of dimethylated psoralen and angelicin in the 4′, 5′-position leads to the formation of 1,3-dioxane derivatives, resulting from the condensation of an 1,3-dioxane ring to the 4′, 5′-positions of the dihydrofurocoumarin moiety. The structures of these new compounds, 4a, 1 1a-dihydro-4a, 11a-dimethyl-8H-pyrano [3′, 2′∶5,6]benzofuro[3,2-e]-1, 3-dioxan-8-one (C15H14O5) (1) and 7a, 11a-dihydro-7a, 11a-dimethyl-2H-pyrano[2′, 3′∶4, 5]benzofuro[3, 2-d](1, 3)dioxan-2-one (C15H14O5) (2) have been assigned by1H and13C NMR measurements, mass spectrometry results, and X-ray analysis. Compound (1): triclinic,P¯1,a=9.847(2),b=8.927(2),c=8.334(2) Å,α=95.98(2),β=108.81(3), γ=106.73(3)°; compound (2): triclinic,P¯1,a=7.296(4),b=7.481(2),c=11.812(4) Å,α=91.67(2),β=95.97(4), λ=94.20(3)°. The structures were solved by direct methods and refined by full-matrix least squares toR=0.050 (1) and 0.056 (2). In both compounds the coumarin rings can be regarded as coplanar, while the five-membered ring adopts an envelope conformation and the 1,3-dioxane ring a chair conformation.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01161433

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Characterization of isomeric dimethylfuranocoumarins by electron impact ionization and surface and gaseous collision activation mass spectrometry (1989)

Horning, S. R. ; Bier, M. E. ; Cooks, R. G. ; [et al.]

Chichester : Wiley-Blackwell

Biological Mass Spectrometry 18 (1989), S. 927-934

add to mindlist on the mindlist

Details

ISSN: 0887-6134

Keywords: Chemistry ; Analytical Chemistry and Spectroscopy

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Chemistry and Pharmacology

Notes: Five dimethylfuranocoumarin isomers have been examined by conventional electron impact (EI) mass spectrometry and by collisional activation tandem mass spectrometry using collisions upon both gaseous and solid targets. Kiloelectron-volt collision-induced dissociation (CID) experiments were conducted upon the molecular cation (M+.), the molecular anion (M-.) and the protonated molecule ([M + H]+). Low-energy (electron-volt) CID and surface-induced dissociation (SID) experiments were performed on the molecular cation (M+.) as a function of collision energy in order to vary the internal energy deposited into the ion.Characteristic fragment ions were observed in the EI mass spectra of each isomer, which allowed for their clear distinction. High-energy CID performed on the molecular cation (M+.) yielded similar daughter ion spectra for each isomer, although small variations in the relative intensities of selected fragment ions allowed for their distinction. Nearly identical CID spectra were obtained for the molecular anions and protonated molecules. Low-energy CID performed upon the molecular cation under multiple-collision conditions at collision energies ranging from 10 to 29 eV yielded nearly identical daughter ion spectra for all but one isomer, suggesting that isomerization to a common ion structure may have occurred. By contrast, ion/surface (SID) collisions on M+. were highly effective in distinguishing the various isomers in that characteristic fragment ions were obtained for each compound. Remarkable features of the SID data are the extensive degree of fragmentation recorded for these aromatic molecules, and the reduced tendency of the activated ion to undergo rearrangement to a common ion structure.

Additional Material: 2 Ill.