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Please login or sign up for a free trial to access the full content. Method 2: From 5- and 3-(2-Aminophenyl)-1,2,4-oxadiazoles

DOI: 10.1055/sos-SD-016-00745

Kikelj, D.Science of Synthesis, (200416634.

Hydrogenolytic ring opening of 5-(2-aminophenyl)-1,2,4-oxadiazoles 125 and subsequent cyclization of the resulting intermediates affords 2-substituted quinazolin-4(3H)-ones 5 in good yields (Scheme 75).[‌469‌,‌470‌] Similarly, hydrogenolysis of the isomeric 3-(2-aminophenyl)-1,2,4-oxadiazoles 126 gives isolable N-[amino(2-aminophenyl)methylidene]carboxamides 127, which on acidification undergo spontaneous cyclization to 2-substituted quinazolin-4-amines 52 (Scheme 76).[‌471‌,‌472‌] These reactions proceed analogously when a masked 2-amino moiety (e.g., nitro, benzylamino) is present in 125 or 126, which is transformed to the amino group under the applied reaction conditions.

Meeeee 88 Meeeeeeeee-8(8M)-eeee eeee 8-(8-Meeeeeeeeee)-8,8,8-eeeeeeeeeee[‌888‌,‌888‌]

Meeeee 88 Meeeeeeeee-8-eeeeee eeee 8-(8-Meeeeeeeeee)-8,8,8-eeeeeeeeeee[‌888‌,‌888‌]

Meeeeeeeeeee Meeeeeeee

8-Meeeeeeeeeeeeeee-8(8M)-eee (8, M8=Me); Meeeeee Meeeeeeee:[‌888‌]

M eeeeeee ee 8-eeeeee-8-(8-eeeeeeeeeee)-8,8,8-eeeeeeeeee (8.8e, 88.88eeee) eee 88% Me/M (8.8e) ee MeMM (888eM) eee eeeeeeeeeeee ee ee eeee e Meee eeeeee eeee ee eeeeeee eeeeeeee ee 8888Meee ee M8 eee 88eee. Mee eeeeeee eee eeeeeeee eee eeeee eeeeeee ee eee eeeeeee eee eeeeeee eee eeeeeeeeeeeeee (MeMM); eeeee: 8.8e (88%); ee 888.8°M.

8-Meeeeeeeeeeeeeee-8-eeeee (88, M8=Me); Meeeeee Meeeeeeee:[‌888‌]

M-[(M)-Meeee(8-eeeeeeeeeee)eeeeeeeeeee]eeeeeeeee (888, M8=Me):

M eeee ee 8-(8-eeeeeeeeeee)-8-eeeeee-8,8,8-eeeeeeeeee (888, M8=Me; M8=MM8; 8.88e, 88eeee) ee MeMM (888eM) eee eeeeeeeeeeee eee 88eee eeee 8% Me/M (8.8e). Meeee eeee eeee eee eeee eee eeeeee eeeeeeeee eeeee. Me eee eeeeeeee eee eeeeeeeeee ee eeeee ee 88°M eeeeeee. Mee eeeeeee eee eeeeeeeeeeee (Me8M/eeeeee) ee eeee eee eeeeeee; eeeee: 8.8e (88%); ee 8888°M.

8-Meeeeeeeeeeeeeee-8-eeeee (88, M8=Me):

M eeeeeeeeee ee 888 (8.88e, 88eeee) ee M8M (88eM) eee eeeeeeeee eeee e eee eeeee ee 88% ee MMe ee eeee e eeeee eeeeee eeee, eeeee eeeeeee ee eeeeeeeee eeeee e eee eeeeeee. Mee eeee eee eeee eeeeeeee eee eee eeeeeee eeeeeeeeeeee; eeeee: 8.88e (88%); ee 888888°M.