Condensation of 5a,6-dihydro-5a,6,6-trimethyl-2-nitro-12H-indolo[2,1-b][1,3]benzoxazine derivatives with ortho-hydroxy-substituted aromatic aldehydes afforded 1′-(2-hydroxy-5-nitrobenzyl)spiro[1-benzopyran-2,2′-indoline].
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