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NOTES 377 were led to compare the analogous reaction using /3-chlorovinyldichloroarsine as described by Lewis and Stiegler [This Journal, 47, 2546 (1925) ]. They found (loc. tit., p. 466) that not only is 10-chloro-5,10-dihydrophenarsazine and not "6-chlorovinylphenarsazine" formed by the action of /3-chlorovinyldichloro-arsine on diphenylamine, but, by proving the production of vinyl chloride in the reaction, showed that the course of the latter may be expressed

') have described a delicate qualitative color test for reactive organometallic compounds. Later, the same authors ' ) showed that the test worked quite satisfactorily with some tertiary Grignard reagents such as : the fert.-butylmagnesium halides, terf.-amylmagnesium chloride and methyldiethylmethylmagnesiumchloride, General details concerning the test are given elsewhere',2. The test is of great utility, and has been extensively employed. First, it removes a great deal of arbitrary and frequently useless operations in studies concerned with reactive organometallic compounds. For example, in Grignard reactions the test is only shown when the -MgX group is attached to carbon. Accordingly if equivalent quantities of RMgX compound and the other reactant (let us assume here, a ketone) are brought into reaction a very definite way to determine when the reaction is complete is to remove a small sample (0.5 to 1 cc.) of the solution and make the color test. When the reaction is complete (and if an excess of organometallic compound has not been taken) there will be no positive color test inasmuch as the -CMgX grouping has been replaced by an -0 M g X grouping.Obviously this removes the necessity of the usual prolonged 3, digestion in many reactions, and tells with certainty when the organometallic compound has been used up and the reaction ended.Second, the color test informs one as to the number of equivalents of Grignard reagent that are necessary in order to complete a reaction that requires more than one equivalent of RMgX compound ' ). Third, the color test is a ready means of determining with very small (CH,)(C*H,),CMgCl. I ) Gilman and Schulze, J. Am. Chem. SOC. 47, 2002 (1925).? ) Gilman and Schulze, Bull. SOC. chim. 41, 1479 (1927). -) A number of studies now in progress show that many of the more commonly used compounds react quite rapidly with Grignard reagents. The same studies show that there are definite differences in reactivity of unlike Grignard reagents towards a given compound under corresponding conditions. Furthermore, these studies (all of which employ the color test) show that the members of a given series of compounds (for example, the ketones) react at different rates, under corresponding conditions. with a given RMgX compound.' ) Gilman and McCracken, J. Am. Chem. SOC. 49, 1052 (1927).

was cleared by filtration, then treated with 10 g. of methyl iodide and set aside until the scarlet color had disappeared. The pale yellow solution thus formed was extracted with ether, the ethereal solution dried over sodium sulfate and allowed to evaporate. It deposited a mixture of yellow needles and a pale yellow high-melting powder.The yellow needles were extracted with cold acetone and ultimately purified by recrystallization from ether. Like the methyl ether of the Grignard product, this methyl ether of the methyl alcohol addition product loses formaldehyde at the melting point, 175-180°.