ChemInform Abstract: Synthetic Approaches to 3-Amino-1,4-naphthoquinone-2-carboxylic Acid Derivatives and Photochemical Synthesis of Novel 1,4,5,10-Tetrahydro-5, 10-dioxo-2H-naphth(2,3-d) (1,3)oxazine Derivatives

Synthesis of 3-alkylamino-1, 4-naphthoquinone-2-carboxylic acid (2) was attempted. Although 3-(1-piperidinyl)-1, 4-naphthoquinone-2-carboxylic acid (2a) was not obtained, probably because of its instability, the esters (18a, b)of 2a could be prepared. 2-Alkylamino-3-hydroxymethyl-1, 4-naphthoquinones (9a-g) were photochemically cyclized to the 1, 4, 5, 10-tetrahydro-5, 10-2H-naphth[2, 3-d][1, 3]oxazines (19a-g), containing a novel heterocyclic ring system in moderate yields. Anti-bacterial activity of the prepared compounds was weak or insignificant.