peri-Naphthylenediamines - 26. Unexpected formation of naphtho[1,8-c,d]pyran derivatives in the reaction of 1,8-bis(dimethylamino) naphthalene with trifluoroacetic anhydride. A new type of double naphthalene "proton sponges"

The reaction of 1,8-bis(dimethylamino)naphthalene ("proton sponge") with tr ifluoroacetic anhydride afforded new derivatives of naphtho[1,8-c,d]pyran, viz., trans- (4) and cis-1,3-dihydroxy-6,7-bis(dimethylamino)-1,3-bis(trifl uoromethyl)-1H,3H-naphtho[1,8-c,d]pyran (5) and symmetrical 3,4,10,11-tetra kis(dimethylamino)-7,14-bis(trifluoromethyl)-7,14-epoxy-dinaphtho[1,8-a,b; 1',8'-ef]cyclooctane (3), which belongs to a new type of double "proton spo nges," along with the expected 1,8-bis(dimethylamino)-4-trifluoroacetylnaph thalene. The structures of compounds 3 and 4 were established by spectral s tudies and X-ray diffraction analysis.