THE GRIGNAED REAGENT ON 0-PHTHALIC ESTERS. 



O 



in terephtlialic acid lie on tlie same side in space and must, 

 therefore, to a certain extent, have a hindering influence upon 

 each other on carrying out the Grignard's reaction. This again 

 is not the case. 



On the other hand, both I and II satisfy the main con- 

 dition that the two carboxyl groups in o-phthalic acid are in the 

 CIS-position, while those in terephtlialic acid are in the trans- 

 position. 



The choice between these two is not so easy. But, as will 

 be shown hereafter (p. 12), I have obtained 1 : l-diphenyl-3- 



C(CüH5)2v 



phenylene-phthalane, CgH4<^ yO, by the action of phenyl 



magnesium bromide upon o-phthalic acid diethyl ester, tliis com- 

 pound being, no doubt, produced through the intermediate 



formation of the alcohol, C6H4<^ /O, as already in- 



\C(CoH,3)(OH)^ 



dicated above in a general way, and the alcohol then losing water 



from the group /C\ • Now, there are three possible ways, 



in which water may be separated from this group, according as 

 the condensation occurs in the oriho-, or the meta-, or the para- 

 position, and producing either one or the other of the following 

 three double rings : 



(A) ■ (B) (C) 



Referring to formulae I and II which, as already indicated above, 

 are to be preferred to formuke III and IV, we shall easily find 



