39891-79-7Relevant 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 (2015/05/13)
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).
TRANSFORMATIONS OF o-NAPHTHOQUINONE DIAZIDES IN ALIPHATIC ALCOHOLS
Ponomareva, R. P.,Komagorov, A. M.,Andronova, N. A.
, p. 140 - 149 (2007/10/02)
During photodecomposition and thermal decomposition in hydroxyl-containing media (alcohols, water) o-naphthoquinone diazides in electronically excited and vibrationally excited states eliminate nitrogen, forming the corresponding ketocarbenes.The singlet ketocarbenes undergo intramolecular transformation (with ring contraction and the formation of 3-indenecarboxylic acid or its esters) and intermolecular transformation, forming 1,2-hydroxyalkoxynaphthalenes in reaction with alcohols.The triplet ketocarbenes undergo intermolecular transformations, forming 1- or 2-hydroxynaphthalenes.The composition and ratio of the final products from the decomposition of o-naphthoquinone diazides in alcohols depend significantly on the nature of the alcohol, the presence of oxygen, the presence of radical acceptors, and the spectral composition of the exciting light.
