20686-65-1Relevant articles and documents
Photo-Wolff rearrangement of 2-Diazo-1,2-naphthoquinone: Stern-Volmer analysis of the stepwise reaction pathway
Ladinig, Manfred,Ramseier, Markus,Wirz, Jakob
, p. 678 - 683 (2015)
Abstract 2-Diazo-1,2-naphthoquinone (1) and its derivatives are the photoactive components in Novolak photoresists. A femtosecond infrared study has established that the photoreaction of 1 proceeds largely by a concerted Wolff rearrangement yielding the ketene 1H-inden-1-ylidene-methanone (3) within 300 fs after excitation, but earlier trapping studies gave evidence for a minor reaction path via a carbene intermediate 1-oxo-2(1H)-naphthalenylidene (2) with a lifetime of about 10 ps. Here, we provide a quantitative assessment of the stepwise pathway by Stern-Volmer analysis of the trapping of 2 by methanol to yield 2-methoxy-1-naphthol (4). We conclude that the lifetime of the carbene 2 is at least 200 ps. Moreover, [3 + 2]cycloaddition of 2 and acetonitrile yielding 2-methylnaphth[2,1-d]oxazole (5) was observed. A comparison of the yields of 5 formed upon photolysis and upon thermolysis of 1 in acetonitrile provides evidence that a substantial part of the hot nascent carbene 2 formed photolytically rearranges to the ketene 3 during its vibrational relaxation (hot ground-state reaction). A quantitative assessment of the stepwise versus concerted photodeazotization pathways of 2-diazo-1,2-naphthoquinone (1) forming ketene 3 is provided. Trapping of the carbene intermediate 2 by methanol yields 2-methoxy-1-naphthol (4) in up to 12% yield. [3+2]Cycloaddition of 2 and acetonitrile yielding 2-methylnaphth[2,1-d]oxazole (5) was also observed. The lifetime of the thermalized carbene 2 is at least 200 ps. A comparison of the yields of 5 formed upon photolysis and upon thermolysis of 1 in acetonitrile provides evidence that a substantial part of the hot nascent carbene 2 formed photolytically rearranges to the ketene 3 during its vibrational relaxation (hot ground-state reaction).
Efficient synthesis of 2-substituted benzoxazoles via Beckmann rearrangement of 2-hydroxyaryl ketoximes using diethyl chlorophosphate
Sardarian,Shahsavari-Fard
experimental part, p. 1391 - 1393 (2009/04/06)
An efficient method for synthesis of 2-substituted benzoxazoles has been developed using diethyl chlorophosphate. 2-Hydroxyaryl ketoximes are efficiently converted to benzoxazoles by heating in the presence of diethyl chlorophosphate via Beckmann rearrangement of ketoxime in excellent yields. This method avoids the use of strong acids, harsh conditions, and long reaction times. Georg Thieme Verlag Stuttgart.
One-step reductive amidation of nitro arenes: Application in the synthesis of Acetaminophen
Bhattacharya, Apurba,Purohit, Vikram C.,Suarez, Victor,Tichkule, Ritesh,Parmer, Gaurang,Rinaldi, Frank
, p. 1861 - 1864 (2007/10/03)
A novel thioacetate mediated one-step reductive acetamidation of aryl nitro compounds was developed and applied to an efficient synthesis of acetaminophen. The reaction also proceeds well without a solvent in the presence of a catalytic amount of surfactant.
