The preparation of the 7-nitro-lH-3, 4-dihydro-2, 3-benzoxazine (IIa) and 6-nitro isomer (Va) was carried out directly (see Scheme I) by nitrating 3-acetyl-lH-3, 4-dihydro-2, 3- benzoxazine (IC);, the two isomers IId and Vd were separated by fractional crystallization. For the assignment of the position of the KO2 group in the benzene ring, these compounds were deacetylated to IIa and Val which were hydrogenolyzed to a1, 4-diamino-o-xylene ( ...