2- Methyl-2,3,5,6- tetrahydro-77/pyrido -1,4-benzoxazin-3-ones

Reaction of 2,3-dihydro-3-hydroxy-3-methyl- 240 (R = Me), or a mixture of 2,3-dihydro-3-hydroxy-3-aryl-57/-pyrido[l,2,3-dfe]-l,4-benzoxazin-5-ones 240 (R = Ar) and (8-aroylmethoxy)quinolin-2(l//)-ones 241 (R = Ar) with ethyl 2-(bromomethyl)acrylate in the presence of activated Zn and hydroquinone gave 8-[(2,3,4,5-tetrahydro-4-methylidene-5-oxo-2-furanyl)-methoxy]quinolin-2(l//)-ones (242) (97HCA1161). 6,7-Dihydro derivatives of 240 reacted similarly (00HCA349). 

Reaction of 8-amino-2,5,6,7-tetrahydro-3//-pyrido[l,2,3-de]-l, 4-benzox-azin-3-one with tetrahydrophthalic anhydride gave 100 (91EUP406993). The hydroxy group of 9-[2,2,2-trifluoro-l-hydroxy-l-(trifluoromethyl)-ethyl]-2,3-dihydro-5//-pyrido-[l, 2,3-de]-l,4-benzoxazin-5-ones was acy-lated (79GEP2854727). Treatment of 9-fluoro-10-phenyl-3-methyl-7-oxo-2,3-dihydro-7//-pyrido-[l,2,3-de]-l,4-benzoxazine-6-carboxylate with CISO3H afforded the 10-(p-chlorosulphonylphenyl) derivative, which was converted to the 10-(p-aminosulphonylphenyl) derivative with NH3 (86EUP184384). 

---