68 PROCEEDINGS OF THE AMERICAN ACADEMY 



the action of potassic nitrite on benzylchloride,* and of (11) anthra- 

 chinone from the oxidation of isatropic acid t should be mentioned. 



Discovery and Syntheses of Phenanthrene. 



It is highly probable that Fritzsche,t in 1867, encountered 

 phenanthrene in studying the higher fractions of coal-tar with his 

 reagent, as he describes a hydrocarbon melting near 100° ; this obser- 

 vation was entirely overlooked, however, and we owe the first definite 

 statements about phenanthrene to Fittig,§ who announced its dis- 

 covery in August, 1872 ; but his preliminary notice of it was so 

 imperfect that Glaser, who discovered it at about the same time, sent 

 it to Graebe || for investigation as a new hydrocarbon. In 1873 

 three independent tolerably complete accounts of it appeared almost 

 simultaneously in the Annalen der Ckemie ; these were by Fittig and 

 Ostermayer,1[ by Graebe,** and by Hayduck.tf 



In Graebe's article the synthesis of phenanthrene by passing stil- 

 bene or di benzyl through a red-hot tube is described, whereas Dreher 

 and Otto,|| who tried the same experiment in 1870, before the discov- 

 ery of phenanthrene, naturally overlooked it. 



In the following year Graebe §§ added toluol to the substances, 

 which form phenanthrene under these conditions ; and Barbier |||| an- 

 nounced that Fritzsche's phosene (see page 64) was a mixture of anthra- 

 cene and phenanthrene, since he succeeded in getting the characteristic 

 test, brown plates, with Fritzsche's reagent (dinitroanthrachinone) 

 from such a mixture. Armed with this test, he then proceeded to 

 examine the anthracenes from various syntheses, and found phenan- 

 threne in those made by the action of heat on styrol and benzol, ethy- 

 lene and benzol, benzyltoluol, phenylxylol, and diphenylmethane ; also 

 in the anthracene made from benzylchloride by heating with water, 

 and in that from natural alizarine by reduction with zinc-dust ; as in 

 all these cases the phenanthrene could not be detected by any other 

 test except Fritzsche's reagent, there seems good reason for receiving 

 these results with caution, especially as he himself ha3 proved by 

 direct experiment HIT that anthracene cannot be converted into phe- 



* Brunner, Ber. d. ch. G., '76, p. 1744. f Ann. Chein. Pharm., clxvi. 861. 



t Fittig, Ber. d. ch. G., '79, p. 1739. ** Ibid., cl.wii. 131. 



X Zeitsclir. fur Cliem., '67, p. 293. tt Ibid., elxvii. 177. 



§ Bor. d. ch. G., '72, p. 933. W Ibid., cliv. 170. 



II Ibid., p. 968. §§ Ber. d. ch. G., '74, p. 48. 

 nil Comptes llendus, Ixxix. 121, G60, 810; Ann. Chim. Phys., ser. 5, vii. 515. 

 Ill Ann. Chira. Piiys., ser. 5, vii. 515. 



