- Unprecedented Formation of 2,5-Diaminoquinones from the Reaction of Vanillin with Secondary Amines in Aerobic Conditions
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Vanillin is widely used as a flavoring agent in foods, perfumes and in several other applications. Even if huge amounts of vanillin are annually employed in these manufacturing processes, its reactivity is underexplored, especially for the formation of potentially toxic substances. In this context, we observed the formation of orange to red crystalline compounds in the reaction of vanillin with secondary amines in aerobic conditions. NMR and HRMS allowed identifying the products as 2,5-diamino-1,4-benzoquinones. Preliminary investigations of this reaction led to a proposed mechanism involving an oxidative fragmentation of vanillin as the key step. MTT tests did not show any toxic effect up to 0.1 mm.
- Barbero, Mauro,Papillo, Valentina A.,Grolla, Ambra A.,Negri, Roberto,Travaglia, Fabiano,Bordiga, Matteo,Condorelli, Fabrizio,Arlorio, Marco,Giovenzana, Giovanni B.
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supporting information
p. 136 - 139
(2019/12/27)
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- Studies on Quinones X. On the Reaction of p-Benzoquinone with Secondary Aliphatic Amines
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p-Benzoquinone (1) reacts with dialkylamines 2a-d to 2-dialkylamino-p-benzoquinones 3, 2,5-bis-dialkylamino-p-benzoquinones 4, 2-dialkylamino-8-hydroxydibenzofuran-1,4-quinones 5, and in pyridine also to 2-dialkylamino-5-p-hydroxy-phenoxy-p-benzoquinones 6. A method affording almost exclusively 3 has been developed which is also applicable to compounds 2e-h.
- Ott,Pinter
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p. 901 - 909
(2007/10/03)
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- LIQUID-PHASE OXIDATION OF PHENOL TO p-BENZOQUINONE CATALYZED BY CUPRIC ACETATE AND POTASSIUM THIOCYANATE. A KINETIC STUDY
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Phenol in dimethylformamide is oxidized by O2 at 35 kg cm-2 with the homogeneous catalysis of Cu(OAc)2+KSCN, at temperatures in the range from 49 to 102 deg C, using a steel autoclave.For some of the runs, this was PTFE-lined.Besides p-benzoquinone, phenyl acetate was regularly produced, usually with selectivity of 3-4percent, independent of conversion.Selectivity for p-benzoquinone was about that required by the material balance at low temperature and conversion levels, but decreased when conversion was increased.A separate test proved that p-benzoquinone, put in a solution of Cu(OAc)2 and KSCN in DMF, disappears with first-order kinetics.The system is discussed using a kinetic model of parallel-consecutive reactions.
- Beltrame, Paolo,Beltrame, Pier Luigi,Bussola, Marzio,Carniti, Paolo
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p. 141 - 146
(2007/10/02)
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