4-, 5-, 6-, and 7-Nitro-3- (α-nitrobenzylidene) phthalides were obtained by the Gabriel's reaction using the corresponding nitro-3-benzylidenephthalides and nitrogen dioxide. The products appeared to consist of two isomeric components. 5-, 6-, and 7-Nitro-3- (α-nitrobenzylidene) phthalides were reacted with hydriodic acid and red phosphorus to obtain 6-, 7-, and 8-amino-3-phenylisocournarins. Their fluorescence maxima shifted toward longer wavelength in the order of 7->8->6-amino or acetylamino derivatives. The fluorescence intensities, however, were rated in the following order : 8->7->6-amino or acetylamino derivatives. The ultraviolet absorption spectrum and the fluorescence spectrum of 3-phenylisocoumarin were also compared with those of 3-phenylcoumarin and trans-stilbene.
Magnesium metal was found to react fairly rapidly with halogenobenzenes under sufficiently anhydrous conditions to give soluble organomagnesium compounds in good yields. The organomagnesium compounds so obtained showed empirical formulas whose halogen contents decreased in the order of Cl>Br>I. Isoprene was polymerized using the catalyst system composed of the above organomagnesium compounds and titanium tetrachloride. When the molar ratio of organomagnesium compound to titanium tetrachloride (Ar-Mg/Ti) was above 2, high cis-1, 4-polyisoprenes were obtained. At the Ar-Mg/Ti ratio below 2, however, powderly polymers containing cyclic structures were formed in low yields. The extent of reduction of titanium tetrachloride with the magnesium components was also determined in relation to the Ar-Mg/Ti ratio.