NOTES
SEPTEMBER, 1962
3337
Desulfonation of Nitro Tobias Acids.-A mixture of 5 g. this manner, as after one recrystallization, the 5(18.65 m o l e s ) of the nitrated Tobias acid and 70 ml. of isomer is essentially eliminated. The formation 45% sulfuric acid was refluxed 40 min. It was diluted while of as much as 85% of the 8-nitro compound com- hot to 1 1. and made alkaline with sodium hydroxide solupares favorably with the 50% yield of 8-nitro tion. The suspension was cooled to 10" for 1.5 hr., and the derivative obtained on nitration of @-naphthyl- precipitated material filtered, washed with water, and dried; ~ h t h a l i m i d e . ~The ? ~ removal of the phthalimide yield, 3.10 g. or 88%. The yield is poorer with nitro Tobias acid which has been stored for some time. When group is so difficult that the method was abandoned recrystallized once from aqueous methanol, almost all of the by Ward and WellsBas a preparative process for 5-isomer was eliminated. The 8-nitro-2-naphthylamine 5- or 8-nitro-2-naphthylamines. On the other thus obtained, was recrystallized from aqueous methanol hand, the nitro Tobias acids can be desulfonated and from benzene-hexane, and had m.p. 104-105.5". intimate mixture with material obtained by the proceeasily to form these nitroamines. The production An dure of Saunders and Hamilton'had m.p. 104-106". Hodgof the 8-nitro-2-naphthylamine in this way avoids son and Ratcliffen give 104.5-105". The infrared spectrum the use of the carcinogenic 0-naphthylamine by was identical with that of authentic material.' substitution of the presumably innocuous Tobias (8) H. H. Hodgson and J. Ratoliffe, J . Chem. SOC.,1040 (1949). acid. It also provides a starting material for an alternative route to 1,7-dinitronaphthaiene and to the 1,7-diamine. The preponderance of 8-nitration may be as- A New Type of Ring-Opening Polymerization scribed to the peri influence of the 1-sulfonic group TERUAKI MUKAIYAMA, TAMOTSU FUJISAWA, as naphthalene-1-sulfonic acid has long been known HIROYUKI NOHIRA,AND TERUO HYUGAJI to nitrate in the 8 (peri) position, this being the first step in the commercial process for 8-aminoLaboratory of Organic Chemistry, naphthalene-1-sulfonic acid (peri acid). Tokyo Institute of Technology, Prior acetylation of the amine group in Tobias Meguro-Ku, Tokyo, Japan acid did not change greatly the isomer distribution in the product, and no &nitration was observed as Received March 23,1963 is the case with 2-a~etylaminonaphthalene.~J The mixture of nitro Tobias acids could not be The reactions of diethyl N-phenyliminocarbonseparated because of close similarity in properties. ate and cyclic iminocarbonates with acids, such It was therefore analyzed directly. as hydrogen chloride, carboxylic acids, and phosDinitration of Tobias acid was not successful phoric acid, have recently been reported to afford and no identifiable product was isolated on at- ethyl N-phenylcarbamate and the corresponding tempted nitration of 2-aminonaphthalene-l,5-di- esters, and compounds containing urethane and sulfonic acid (sulfonated Tobias acid). ester linkages, respectively, as shown in the following equations.' Experimental Nitration a t 0" or above resulted in desulfonation and formation of brown amorphous material. Temperature control was therefore important and a Dry Ice-alcohol bath was used. Nitro Tobias Acids.-Concentrated sulfuric acid (96y0, 120 ml.) was cooled to -5 to -10" and treated slowly with 11.15 g. (0.05 mole) of Tobias acid with stirring. Most was soluble and the liquid was cooled further to -15' and addition of dry powdered potassium nitrate was started. A 6-g. sample (0.059 mole) of this was added in 20 min. while keeping the temperature between -10 and -16". The brown solution was stirred 40 min. in this temperature range itrid then poured onto 0.5 kg. of ice. The precipitated pr(JdUCt was filtered off and washed, and then extracted with cold dilute sodium carbonate solution. The filtered extracts were cooled to 5" and acidified with hydrochloric acid. After 3 hr. on ice, the tan crystalline powder was filtered off, washed with ice water, and dried. Two runs gave yields of 12.65 g. (94.4%) and 12.85 g. (95.99;b). This product did not change on boiling its solution in sodium carbonate, but decomposed partly on storage for several months at room temperature. It was vacuum dried for analysis. A n a l . Calcd. for CloHsSOs: S, 11.94. Found, S, 11.96. (5) H. H. Hodgson and J. H. Crook, J . Chem. Sac., 1844 (1936). (6) E. R . Ward and P. R. Wells, ibid., 4859 (19.61). (7) C. R. Aminders and C. S. Hamilton, J . A m . Chem. Soc., 64, 636
(1932).
+
C,Hb-K=C
