ChemInform Abstract: 1H-NMR Studies on Compounds with Bridgehead Nitrogen. Part 31. Reversible Dimerisation of Perhydropyrido[1,2-c][1,3]oxazepines; X-Ray Analysis of a Fourteen-membered Macrocyclic Dimer; Conformational Analysis of Perhydropyrido[1,2-c][

1977 ◽  
Vol 8 (3) ◽  
pp. no-no
Author(s):  
R. CAHILL ◽  
T. A. CRABB ◽  
D. A. WHITING
Keyword(s):  
Conformational Analysis ◽  
1H Nmr ◽  
Nmr Studies ◽  
X Ray ◽  
Bridgehead Nitrogen

Article

1999 ◽  
Vol 77 (5-6) ◽  
pp. 1057-1065
Author(s):  
John T Edward ◽  
Francis L Chubb ◽  
Denis FR Gilson ◽  
Rosemary C Hynes ◽  
Françoise Sauriol ◽  
...  
Keyword(s):  
Nmr Spectra ◽  
Acidic Solution ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Cage Compounds ◽  
Amine Nitrogen ◽  
X Ray ◽  
Bridgehead Nitrogen ◽  
C Nmr

Three new cage peroxides, 1,6-diaza-3,4,8,9-tetraoxabicyclo[4.4.2]dodecane (3a),1,6-diaza-3,4,8,9-tetraoxa-11-methylbicyclo[4.4.2]dodecane (3b), and 1,6-diaza-3,4,8,9-tetraoxatricyclo[4.4.2.411,12]hexadecane (4), have been prepared by reaction of 1,2-diaminoethane, 1,2-diaminopropane, and trans-1,2-diaminocyclohexane, respectively, with formaldehyde and hydrogen peroxide in aqueous acidic solution. Their structures have been established by X-ray diffraction, and show the bridgehead nitrogen atoms to be predominantly sp2 hybridized. The structures accord with 1H and 13C NMR spectra. Variable temperature NMR studies show that the diperoxide 3a begins to undergo rapid inversion (on the NMR time scale) at about 303 K; up to 370 K the diperoxides 3b and 4 show no conformational change.Key words: cage compounds, formaldehyde, peroxides, amine nitrogen, hybridization.

scholarly journals Short-Chained Anthracene Strapped Porphyrins and Their Endoperoxides

2020 ◽  
Author(s):  
Susan Callaghan ◽  
Keith Flanagan ◽  
John E. O'Brien ◽  
Mathias Senge
Keyword(s):  
Singlet Oxygen ◽  
1H Nmr ◽  
Absorption Spectroscopy ◽  
Cycloaddition Reactions ◽  
Nmr Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
Polychromatic Light

The synthesis of short-chained anthracene-strapped porphyrins and their Zn(II)complexes are reported. The key synthetic step employed was a [2+2] condensation between a dipyrromethane and 2,2'-((anthracene-9,10-diylbis(methylene))bis(oxy))dibenzaldehyde. Following exposure to polychromatic light, self-sensitized singlet oxygen and the anthracene moieties underwent [4+2] cycloaddition reactions to yield the corresponding endoperoxides. 1H NMR studies demonstrate that the endoperoxide readily formed in chloroform-d and decayed at 85 °C. X-ray crystallography and absorption spectroscopy were used to confirm macrocyclic distortion in the parent strapped porphyrins and endoperoxides. Additionally, X-ray crystallography indicated that endoperoxide formation occurred exclusively on the outside face of the anthracene moiety.<br>

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