Organic Lab Reactions 270

Organic Lab Reactions 270 - in 46 yield the homolog(V gives...

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INFLUENCE OF SUBSTITUENTS 265 the diazonium chloride is converted into tarry non-volatile sub- stances. * The decomposition of a-naphthalenediazonium acid sulfate in absolute ethyl alcohol yields both naphthalene (40%) and a-ethoxynaphthalene (23%). With the beta isomer much less naphthalene (7%) results, and /3-ethoxynaphthalene is obtained in 30% yield. 12 - 13 Upon heating the tetrazonium chloride derived from benzidine with ethanol, an 80% yield of biphenyl is obtained without any evidence of ether formation. Extreme care is necessary to prevent the reaction from occurring violently. 14 When a methyl group is introduced into the orlho or meta position of aniline, the yield of hydrocarbon falls to zero; only ethers (I and II) are isolated (in 50% and 40% yields, respectively). 10 ' 1S CH 3 Nj+HSOr CH 3 OC 2 H 6 CH 3 CH 3 N 2 +HSO 4 - An interesting example o{ the deleterious effect of an ortho methyl group is to be found in the tetraphenylmethane series. 16 ' 16 While 4- aminotetraphenylmethane (III) is converted to the hydrocarbon (IV)
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Unformatted text preview: in 46% yield, the homolog (V) gives only the ether (VI). NH 2 NH 2 C(C 6 H 6 ) 3 "1. CH, OC 2 H 6 CH, C(C,H 5 ) S IV i C(C e H 6 ), v C(C 6 H 6 ) S VI A methyl group ortho to each of the amino groups in benzidine again exerts a definite effect in favor of ether formation, for, whereas benzidine gives only biphenyl, o-toh'dine yields approximately equal quantities of ether and hydrocarbon. 14 * Tar formation is observed in the reduction of most diazo compounds and is not peculiar to the use of alcohol as the reducing agent. In some instances only slight losses are thus incurred; in others, appreciable amounts of diazonium salt are resinified. 12 Orndorff and Kortright, Am. Chem. J., 13, 153 (1891). " Raiford and Oberst, Am. J. Pharm., 107, 242 (1933). "Winston, Am. Chem. J., 31, 119 (1904). "TJUmann and Milnzhuber, Ber., 36, 408 (1903). M Van Alphen, Rec. trav. chim., 46, 603 (1927)....
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