Nitro l-aminonaphthalene

Alternatively, the thiazolotriazine ring was prepared from l-nitro-2-aminonaphthalene with an isothiocyanate to give naphthylpyrimidine 669, whose reaction with phenacyl bromide gave thiazoline 670. Reduction with stanous chloride and cyclization with (V-bromosuccinimide gave naphthothiazolotriazine 671 (74JIC631) (Scheme 138). 

Similarly, l-nitro-2-aminonaphthalene gives 1-chloronaphthalene in 69% yield and only a trace of 1-nitronaphthalene when diazotized in hydrochloric acid solution and reduced with hypophosphorous acid.83 Upon diazotization with sulfuric acid, however, a 61% yield of a-nitronaphthalene is obtained.83 The same type of side reaction occurs when 2,5-diaminotriptycene (XX) is diazotized in hydrochloric acid solution and then reduced with hypophosphorous acid.87... 

The successful deamination of l-nitro-2-aminonaphthalene, 2,5-diamino-triptycene (XX), and l-bromo-2,5-diaminotriptycene (XXI) suggests that 5-amino-8-nitroisoquinoline (XVIII) also could be deaminated to 8-nitroisoquinoline if the diazotization were carried out in sulfuric acid. 

A mixture of 125 g. of crude acetamino compound, 500 ml. of ethanol, and 125 ml. of hydrochloric acid is heated under reflux for 4 hours. The resulting solution is poured into 3 1. of cold water, and the precipitated l-nitro-2-aminonaphthalene is filtered off and dried. It is recrystallized from two times its weight of ethanol to give 75 g. (59% based on naphthylamine) of product melting at 127°. 

When l-nitro-2-aminonaphthalene is treated with sodium nitrite and HCl, and then with warm water, there is obtained not only l-nitro-2-naphthol, but also l-chloro-2-naphthol. How do you account for the formation of the chloronaphthol Consider carefully the stage at which chlorine is introduced into the molecule. 

Aromatic amines are often acetylated before nitration. Examples include the nitration of p-acetotoluide and 2-acety]aminonaphthalene, the products being 3-nitro-p-acetotoluide (90%) and l-nitro-2-acetylamino-naphthalene (49%), respectively. The p-tolylsulfonyl derivative is readily formed and hydrolyzed after nitration. On the other hand, if unacetylated and in the presence of a large excess of sulfuric acid, p-toluidine gives mainly 2-nitro-p-toluidine (71%), the arylammon um ion being meta-directing. 

Trinitro-l-aminonaphthalene or 2,4,8-Trinitro-l-naphthylamine, orange-yel crysts, mp 189—90°. Was prepd by nitration of 8-nitro- l-toluene-p-sulphonamidonaphthalene in AcOH, followed by hydrolysis in sulfuric acid... 

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