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DOI: 10.1055/sos-SD-110-02056

Harris, P. A.Science of Synthesis Knowledge Updates, (20213146.

6-Acylindolo[1,2-a]quinoxalines 10 are obtained in a two-step one-pot synthesis by condensation of 2-iodo-N-(2-nitrosoaryl)anilines 7 with 1,3-diketones 8 to give 3-methylene-3,4-dihydroquinoxalines 9, followed by Heck cyclization (Scheme 2).[‌4‌] The required 2-iodo-N-(2-nitrosoaryl)anilines 7 are readily obtained directly from the reaction of nitroarenes and 2-iodoanilines in the presence of potassium tert-butoxide.[‌5‌] The reaction only works for monosubstituted 1,3-diketones, indicating that only the acetyl group is reactive enough to condense with the N-arylaniline 7 to form the 3,4-dihydroquinoxaline 9. The use of anhydrous tetrabutylammonium bromide in combination with potassium acetate in the Heck reaction gives the optimal yields.

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