Antiseptic Action and Chemical Constitution. 347 



boiling for a short time; on adding alcohol and cooling the compound 

 crystallised in colourless needles 



[20. 21.] /3-Naphthoquinoline was obtained by the method described byClaus 

 and Besseler,* and purified by crystallisation from petroleum ether. It 

 crystallises in pale yellow leaflets, m.p. 93°. It was converted into the metho- 

 sulphate and chloride (as described under a-naphthoquinoline); cf. the following 

 formulae : — 



[22.] Tetrahydro -a.- naphthoquinoline was obtained, as described by 

 Bamberger,f by the reduction of a-naphthoquinoline with tin and hydro- 

 chloric acid. The base was precipitated from ethereal solution by hydrogen 

 chloride as a crystalline mass which was purified by re-crystallisation from 

 alcohol acidified with hydrochloric acid. After being decolourised with animal 

 charcoal the hydrochloride of the base was obtained in colourless needles, 

 m.p. 257°-8°. 



[23.] Tetrahydro- ft-naphthoquinoline was prepared from the /3-compound, as 

 above, in the form of colourless, lustrous leaflets, m.p. 231°. 



[24.] Diamino - /3 - naphthoquinoline. — Five grms. of ft - naphthoquinoline , 

 with 6 grms. potassium nitrate and 20 c.c. cone, sulphuric acid, were heated on 

 the water-bath for 3 hours. The nitro-compound was poured on to ice and 

 washed with cold water. It was then warmed on the water-bath with dilute 

 ammonia, which dissolved a brown coloured substance. The product was 

 filtered and dried and crystallised from nitrobenzene. It melted at 230°-245°. 

 On a second crystallisation it melted' at 245°-247°. On analysis, 



- 16 grm. gave 21 - 5 c.c. moist N at 18° and 747'5 mm. N = 15'1 per cent. 



a. 



Calculated for Ci 3 H 7 N(]Sr02)2 ; N = 155 per cent. 



* 'J. prakt. Chera.,' vol. 57, p. 49 (1898). 

 t 'Ber.,' vol. 24, p. 2475 (1891). 



