“…The first was prepared in a single step from the imide 10 as noted in Scheme , and the second, 8 , utilized the short sequence in the same scheme using a modified Reich procedure for introduction of the conjugation . Both synthetic reactants 10 and 11 were known. , 1 Synthesis of Two of the Photochemical Reactants…”
Section: Resultsmentioning
confidence: 99%
“…On the basis of excessive crowding a cis - syn - cis dimer appears to be unlikely. In the protium NMR, a downfield signal at 3.41 pm (d, J = 8.6 Hz) is assigned to bridgehead protons α to the carbonyl; a head-to-tail structure would not be expected to give a sharp doublet …”
Section: Resultsmentioning
confidence: 99%
“…The residue was dissolved in 15 mL of acetic acid treated with 5.0 mL of sulfuric acid and refluxed for 2 h. After cooling to ambient temperature, the mixture was poured onto crushed ice, and the crude product was filtered and dried. Crystallization from ethanol afforded 2.56 g (70.0%) of 5-methyl-3,3-diphenylpiperidine-2,6-dione: mp 184−186 °C (lit . 183−186 °C); 1 H NMR (CDCl 3 , 300 MHz) δ 8.00 (br s, 1H), 7.25−7.45 (m, 8H), 7.06−7.09 (m, 2H), 2.66 (d, J = 9.6 Hz, 2H), 2.45 (m, 1H), 1.31 (d, J = 6.3 Hz, 3H); 13 C NMR (CDCl 3 , 75.4 MHz) δ 138.69, 129.30, 128.37, 128.00, 63.83, 21.42.…”
In contrast to the photochemistry of monocyclic aza-cyclohexenones, their counterparts with a second carbonyl group undergo photochemical rearrangements which parallel those of the 4,4-disubstituted cyclohexenones.
“…The first was prepared in a single step from the imide 10 as noted in Scheme , and the second, 8 , utilized the short sequence in the same scheme using a modified Reich procedure for introduction of the conjugation . Both synthetic reactants 10 and 11 were known. , 1 Synthesis of Two of the Photochemical Reactants…”
Section: Resultsmentioning
confidence: 99%
“…On the basis of excessive crowding a cis - syn - cis dimer appears to be unlikely. In the protium NMR, a downfield signal at 3.41 pm (d, J = 8.6 Hz) is assigned to bridgehead protons α to the carbonyl; a head-to-tail structure would not be expected to give a sharp doublet …”
Section: Resultsmentioning
confidence: 99%
“…The residue was dissolved in 15 mL of acetic acid treated with 5.0 mL of sulfuric acid and refluxed for 2 h. After cooling to ambient temperature, the mixture was poured onto crushed ice, and the crude product was filtered and dried. Crystallization from ethanol afforded 2.56 g (70.0%) of 5-methyl-3,3-diphenylpiperidine-2,6-dione: mp 184−186 °C (lit . 183−186 °C); 1 H NMR (CDCl 3 , 300 MHz) δ 8.00 (br s, 1H), 7.25−7.45 (m, 8H), 7.06−7.09 (m, 2H), 2.66 (d, J = 9.6 Hz, 2H), 2.45 (m, 1H), 1.31 (d, J = 6.3 Hz, 3H); 13 C NMR (CDCl 3 , 75.4 MHz) δ 138.69, 129.30, 128.37, 128.00, 63.83, 21.42.…”
In contrast to the photochemistry of monocyclic aza-cyclohexenones, their counterparts with a second carbonyl group undergo photochemical rearrangements which parallel those of the 4,4-disubstituted cyclohexenones.
Methyl methacrylate (MMA) oligomers, obtained by radical polymerization of MMA with substituted 1,1,2,2-tetraphenylethanes, contain one unstable C-C bond which can be cleaved thermally under common polymerization conditions. This was shown by means of gel permeation chromatography, field desorption mass spectrometry and model compounds.
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