1.23.4- Tetrahydro-1 -naphthylamine

Fischer esterification of 5,6,7,8-tetrahydro-l-naphthoic acid, prepared from 5,6,7,8-tetrahydro- 1-naphthylamine via a recently published method [9], produced the methyl ester, which was distilled twice, b.p. 158-5-159° at 15-5 mm (spectral sample), wff 1-5437 lit. [14] values b.p. 93-5-96-5° at 0-5-1-0 mm, f 1-5431. 

Naphthylamine can take up four atoms of H to form two isomeric tetrahydro-naphthylamines I and II which have the Kekule formulae ... 

CA Registry No 2493447-2. It is prepd by bromination of 5,6-dinitro-l,2,3,4-tetrahydro-naphthalene followed by dehydrobromination (Ref 20), from 2-nitro-l-naphthylamine by the same procedure as used for the prepn of the 1,4-isomer (Ref 20)... 

Dinitronaphthalene ( Gamma-dinitronaph-thalene, 1,3-DNN), Bright yel needles from aq pyridine, mp 144°, bp subl (Refs 1 32) CA Registry No 606-37-1. It is prepd by the action of nitric ac/sulfuric ac on naphthalene at low temps (Refs 14 33) by the nitration of 1-MNN with a mixt of 17.3% nitric ac, 61.2% sulfuric ac, and 21.5% w, temp 59-75°, time 90min (Ref 52) by the action of powd Cu (Ref 18) or hydrazine (Ref 22) on l-chioro-2,4-dinitro-naphthalene by the diazotization of 2,4-dinitro-1-naphthylamine followed by redn of the dia-zonium salt with EtOH (Ref 25) or by the action of Br on 5,7-dinitro-l,2,3,4-tetrahydro-naphthalene followed by dehydrobromination (Ref 13). It is used to prep more highly nitrated naphthalenes... 

A marginal hydrogenation of the benzenic ring of 1-naphthylamine leading to 5,6,7,8-tetrahydro-l-naphthylamine [72] was explained as due to a weaker adsorption of the benzene part than of the aniline part of the naphthylamine. However, this reaction was disregarded for the HDN of 1-naphthylamine, as the minor role it could play under the studied conditions. 

Fluorescence arises from aromatic by-products which, however, can be entirely separated by careful work. Pure ac-tetrahydro-/5-naphthylamine gives no color with diazobenzene sulfonic acid. 

The hydrochloride of the ac.-tetrahydro-0-naphthylamine can be obtained readily by neutralizing a dry ether solution of the base with an ether solution of hydrogen chloride. It crystallizes from water in large plates which melt at 237°. 

Up to the present the only method used for the reduction of 0-naphthylamine for obtaining the tetrahydro base has been with sodium and alcohol. This method was first described by Bamberger and Muller.2 It is possible to substitute ethyl alcohol for amyl alcohol but the yield is distinctly lower. The base has been resolved into its optically active components.3... 

Tetrahydro-l-naphthylamine (0.68 mol) and triethylamine (1.36 mol) were dissolved in 1.5 L THE at 0°C to 5 °C and ethyl oxalyl chloride (0.75 mol) added dropwise. The mixture stirred for 30 minutes, the precipitate filtered, and the filtrate concentrated. The residue was recrystallized in ethyl alcohol and the product isolated in 95% yield. H-NMR data supplied. 

An Ullmann reaction between 5,6,7,8-tetrahydro-l-naphthylamine and 2-bromobenzoic acid leads to the 2-[l-napbthylamino]benzoic acid (114), which is cyclised to the benz[c]acrid-7-one in polyphosphoric acid (B.V, Lap et al.,3. heterocyclic Chem., 1983, 20, 281). 

The ether filtrates contain dihydronaphthalene and ar-tetrahydro-/3-naphthylamine. 

Naphthylamin kann durch Natrium/Solventnaphtha/Methanol bei 130-140° zu 2-Amino-5,6.7,8-tetrahydro-naphthalin reduziert werden (Bd.XI/1, S.678ff. erganzend s. Lit.6 7). Mit Natrium in Pentanol bildet sich dagegen 2-Amino-telralinH (51-57% d.Th. Kp12 127,5-128°). 

The naphthylamine is treated with a four- to eight-fold excess of sodium hydrogen sulfite in an aqueous medium at 90-150° for 6-30 hours, the time required varying from case to case this affords the l,2,3,4-tetrahydro-4-oxo-2-naphthalenesulfonic acid which is stable in an acid or neutral medium but decomposes in alkali to sulfite and the naphthol 565 yields are almost quantitative. Moreover, 5-quinolinamine has been converted into 5-quinolinol by this route.566 The reaction fails, however, if there is a sulfo group in the meta-position to the amino group. 

Diarylamines are known to undergo analogous photoinduced electro-cyclizations A -phenyl-l,2,3,4-tetrahydro-5-naphthylamine, for example, is con-... 

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