Naphthalene-1,8-diamine oxidation

Naphthoquinone has been prepared by the oxidation of naphthalene,1 1,4-aminonaphthol,2 1,4-naphthylene diamine,2 and 1,4-naphthylamine sulfonic acid.3 Recent work4 has shown that the oxidation of the 1,4-aminonaphthol is the most convenient method of preparation. 

The nitration of 1 with one equivalent of HNO3 in H2SO4 gave two products the 4-nitro derivative 108 and the binaphthyl proton sponge 36 in 70 and 10% yield, respectively164,187. The reaction proceeds even at —20 °C and is completed within 5 min. These conditions are essentially milder than those for the naphthalene nitration. This is somewhat astonishing, since in such an acidic medium the diamine 1 seems to exist entirely as cation 1 H+, which should be more inert towards electrophiles than the naphthalene itself. One of the reasonable explanations of this discrepancy is that the reaction proceeds via very small equilibrium amounts of the non-protonated 1 or the non-chelated cation l H+-c. Any of them, under the action of the nitronium cation, is oxidized to the radical cation 1+ , which either dimerises or reacts with N02 to give the reaction products 36 and 108 (Scheme 27). There are several indirect pieces of evidence in favour of this. One of them... 

The group of Palmisano and Sisti reported the synthesis of (+)-camphor-based C2-symmetrical diamine ligand (-)-14 and the application of its Cu complex to the asymmetric oxidative coupling of 2-naphthol derivatives (Scheme 3.6). As observed by Kocovsky, Nakajima, and Kozlowski, an ester group installed at the C3 position of the naphthalene is crucial for achieving... 

In 2000, Katsuki and co-workers applied the chiral chloro nitrosyl Ru -(salen) complex developed in their own group to asymmetric aerobic oxidative biaryl coupling reactions (Scheme 3.14). The reaction was found to proceed smoothly in air under irradiation with a halogen lamp as the light source at room temperature. Examination of a series of Ru (salen) complexes revealed that the combination of (R,R)-diamine unit and (R)-BINOL scaffold in the catalyst is important for achieving higher enantioselectivity. The absolute configuration of the major product is determined by the chirality of the BINOL scaffold whereas the structural variation in the diamine part shows little influence on asymmetric induction. Under the optimal conditions, several 2-naphthols with a substituent at the C6 position of the naphthalene... 

In another analytical procedure, the diamine from the diisocyanate is obtained from the filtrate of the acidified alkaline hydrolysis product and can be determined quantitatively by colorimetric methods. If preliminary analysis has indicated 1,5-naphthalene diisocyanate, the filtrate is oxidized with periodic acid and gives a violet-pink colour. For other diisocyanates, colour formation also suitable for colorimetric analysis can be obtained by... 

Ethoxylated diamines Ethoxylated amine oxides Alkyl naphthalene sulfonates... 

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