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Please login or sign up for a free trial to access the full content. Variation 3: By Cyclization of 2-Aminoaryl or 2-Nitroaryl Aryl Ethers

DOI: 10.1055/sos-SD-017-00074

Ulrich, H.Science of Synthesis, (200417101.

When 2-aminophenyl 2-hydroxyphenyl ethers 278 are heated with hydrochloric acid at 195°C, phenoxazines 279 are formed in modest yields (Scheme 88).[‌178‌] Here one might have supposed that dibenzo-1,4-dioxins might be byproducts, but this cannot be the case with bis(2-aminophenyl) ether (280). However, when this compound is heated with 1 equivalent of hydrochloric acid at 250°C for six hours in a sealed tube an equally disappointing 32% yield of phenoxazine (153) is obtained (Scheme 88).[‌178‌]

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