5528 Vol. 79

TABLEV RESOLUTIONOF N-BEXZENESULPOXYL-~-CARBOXYMETHYL-3-SUBSTITUTEDMESIDISESa 111. of solv. Pure less- Rotation in EtOHb Sub- Resolving per g. Purif. sol. salt wt., Vol., stituent Alkaloid solvent acid solvent m.p., "C. g. ml. [OLID, 11 L, =c. SO2 Cinchonine AcOEt 22 XcOEt-MeOH 215-216 0,0557 20 +115.0 23 (3:l) FC Cinchonidine BcOEt 20 lcOEt 125-138 ,0387 5 - 60.7 27 Cinchonine -4cOEt 23 AcOEt-MeOH 201-202 ,0579 5 + 94.1 29 (10:l) C1 Cinchonine AcOEt-MeOH 22 AcOEt-MeOH 198-200 ,0596 5 i106.5 26 (11 : 1) (6:l) Br Cinchonine AcOEt 16 AcOEt-MeOH 200-203 ,0720 20 ilOO.0 23 (15:l) I Cinchonine *Ac@Et-MeOH 24 AcOEt-M eOH 204-205 ,0683 3 -k 114.2 28 (7: 1) (2:l) SH2 Optically active compound prepared by reduction of optically active .

a Only the less-soluble salts are described. X 1-dm. tube was used in all cases. C Resolution of the 3-flUOro acid was attempted with both cinchonine and cinchonidine, but the regenerated acid showed no optical rotation, and all the salt fractions exhibited similar rotation, A check for mutarotation in the cinchonidine salt was negative. Cinchonidine salt: 4naZ. Calcd. for C3sH40FS30sS: C, 66.95; H, 6.24. Found: C, 66 75; H, 6.15. the acid in a manner just described afforded a comparable TABLEVI yield of ( -)-N-benzenesulfonyl-iY-carboxymethyl-3-nitro- mesidine, m.p. 199-200' (resolidified and melted again at RACEMIZATIOS OF 3-BEXZENESULPOXYL-S-CARBOXY- 223-225'); rotation: 0.1225 g. made up to 10 ml. with METHYL- SUBSTITUTED MESIDINES Opt. ethanol at 25" gave CYD-0.14', 11; [cY]~~D-11.4'. Sub- active Rotation in dimethylformaide kSv. X The resolutions of the other compounds in this investiga- stitu- acid, Wt., Vol., [a]D, I, lo-*; t1/2, tion were carried out in a manner similar to that of the nitro ent m.p., OC. g. ml. I1 OC. hr.- hr. compound just described; however, only the less-soluble SO2 196-198 0.9756 10 + 2.4 30 24 1.5 salts were used. Details are summarized in Table IT. $26.6 29 5.7 6.1 Racemization of ( + )-N-Benzenesulfonyl-N-carboxy- C1 202-211 ,8432 20 methyl-3-nitromesidine.-A dimethylformamide solution of Br 219-220 ,3887 20 $22.1 20 5.2 6.7" 0.9756 g. of the (+)-3-nitro acid was made up to 10 ml. and I 188-195 ,4606 20 +29.1 29 5.5 6.3 the racemization carried out at 118" (boiling point of n- SH2 110-115 ,1339 10 +31.4 29 5.7 6.1 butyl alcohol) in a manner described previously.z The followine results were obtained: 0.0 hr.. +0.23': a Reported k,, = 4.4 X hr.-'; ti/% = 8.0 hr. in n- butyl alcohol; for ref. see Table I, footnote b. 0.5 ~~.;-cY~OD$0.17"; 1.0 hr., CY~OD +0.14'; 1.5 hr., +0.12 ; 2.5 hr., a3'D $0.09"; 3.5 hr., cy30D f0.04°.'8 Duplicate racemization experiments were carried out iri A plot of CY ZK. time on semi-logarithmic paper afforded all cases in the same manner. a straight line typical of a first-order rate equation from The average rate constants, half-lives, melting points whose slope was derived the rate constant, k = 2.4 X 10-1 and specific rotations of the optically active acids are sum- hr.-l and the half-life, ti/% = 1.5 hr. marized in Table VI. (IS) In all other cases, a minimum of five points was plotted. URBANA,ILLISOIS

[CONTRIBUTION FROM THE ROHXASD HAASCOMPANY, REDSTONEARSENAL RESEARCHDIVISION] The Oxidation of with BY WILLIAMD. EMMONS RECEIVEDMARCH 14, 1957

Under the proper experimental conditions, peracetic acid is a fairly good reagent for the oxidation of many to . It also can be employed in some cases for oxidation of primary amines to nitroalkanes.

In contrast to previously described results, we also has been described but here, too, complex have found that under suitable experimental condi- mixtures of products resulted. tions peracetic acid is a reasonably efficient reagent Anhydrous solutions of peracetic acid were con- for oxidation of aromatic amines to nitrobenzenes. veniently prepared by the acid-catalyzed reaction The oxidation of both aromatic and aliphatic of acetic anhydride with 90% hydrogen . amines with peracetic acid has been described in the This reaction normally was carried out at ice-bath literature but in most cases relatively poor yields of temperatures in an appropriate solvent. ilfter the nitro compounds were obtained. 1--3 Thus oxida- exothermic formation of peracetic acid had taken tion of with peracetic acid is reported to give place, the aromatic amines were oxidized in the only 11% and the major product is boiling solution. Peracetic acid prepared in this azoxybenzene. The oxidation of aliphatic amines manner is contaminated with small amounts of hy- (1) J. D'Ans and A. Kneip, Bey., 48, 1144 (1915). drogen peroxide and diacetyl peroxide, but these (2) F. P. Greenspan, Ind. Eng. Chem., 39, 847 (1947). impurities do not interfere with the subsequent (3) E. Bamberger and R. Seligman, Bey., 36, 4293 (1902). oxidation reaction. The yields of some typical Oct. 20, 1957 OXIDATIONOF AMINESWITH PERACETICACID 5529 oxidations of aromatic amines are summarized in is not unreasonable. It also should be pointed Table I and refer to purified products. out that the recently described permanganate oxi- dation of t-carbinamines to t-nitroalkanes is a more TABLEI convenient preparation of these compounds, al- OXIDATIONOF AMINESTO NITROBENZENES though it does not appear applicable to the synthe- Yield of nitrobenzene, sis of other nitro alkane^.^ Aniline % It is interesting to contrast the behavior of pera- Aniline 83 cetic acid with that of trifluoroperacetic acid in the p-Toluidine 72 oxidation of aliphatic amines. Under normal con- o-Toluidine 70 ditions the attempted oxidation of an aliphatic amine p-Anisidine 82 simply leads to formation of the amine trifluoro- 2-Amino-p-cymene 72 acetate salt. This is not surprising, since solutions o-dnisidine 70 of trifluoroperacetic acid always contain consider- p-Chloroaniline 62 able quantities of . The latter Ethyl p-aminobenzoate 66 compound is a sufficiently strong acid to protonate substantially all the free amine, and hence the oxi- In several cases trace amounts of highly colored dation does not take place. If, however, the reac- impurities (possibly azoxybenzenes) were formed, tion is carried out in the presence of a heterogeneous but removal of these materials by passage of the buffer system,6it is possible to ob- crude product over a short silica gel chromato- tain a reaction between an aliphatic amine and tri- graphic column proved relatively simple. In con- fluoroperacetic acid. Under these conditions, how- trast to the recently described oxidation of anilines ever, the product obtained is the K-alkyl trifluoro- to nitrobenzenes with trifluoroperacetic acid,4 the acetamide. use of peracetic acid suffers from somewhat lower 0 yields, its failure to oxidize cleanly weakly basic II H amines such as p-nitroaniline, and the impurity of RCHzNHz + CFICOOH +RCHLVCOCFa + HZOZ some of the crude products obtained. On the The yields of this amide were excellent even at tem- other hand, peracetic acid is a considerably cheaper peratures as low as -30'. It is apparent that with reagent and may be used also for the oxidation of strongly nucleophilic amines attack of the nucleo- anilines with electron donating substituents such phile takes place exclusively at the carbonyl carbon as 0- and 9-anisidine. In these two cases oxidation atom, while in the case of aromatic amines, no de- of the amines with trifluoroperacetic acid was not tectable acylation of the amine was observed with successful since the reagent attacked the benzene trifluoroperacetic acid. nucleus. As indicated above, however, oxidation of aromatic amines such as p-nitroaniline with Experimental' strongly electron-withdrawing groups was not a Oxidation of p-Toluidine to p-Nitrotoluene.-To 60 ml. of chloroform stirred vigorously in an ice-bath was added satisfactory reaction with peracetic acid and com- 13.6 ml. (0.5 mole) of 90% and two drops plex mixtures of products were obtained. The oxi- of sulfuric acid catalyst. Acetic anhydride (61.2 g., 0.6 dation of @-naphthylaminewith peracetic acid was mole) was then added dropwise over a 30-minute period. also attempted but here, as was the case with tri- The mixture subsequently was stirred for 15 minutes at room temperature. The clear solution so obtained was di- fluoroperacetic acid, an intractable tar was ob- luted with 40 ml. of chloroform and heated fairly rapidly to tained. In summary then it appears that pera- boiling. The heating mantle was removed, and 10.7 g. cetic acid supplements trifluoroperacetic acid in its (0.1 mole) of freshly distilled p-toluidine in 25 ml. of chloro- ability to oxidize anilines to nitrobenzenes and in form was added over a 20-minute period. The solution many cases the former reagent is satisfactory. boiled vigorously during this addition. The yellow solution was then heated under reflux one hour and poured into 300 The oxidation of aliphatic amines with peracetic ml. of water. The organic layer was separated, washed acid also was examined briefly. Yields of nitroal- with 2 X 100 ml. of 20% aqueous sodium hydroxide solu- kanes obtained from t-octylamine, cyclohexylam- tion and 100 ml. of 10% hydrochloric acid and then finally ine, sec-butylamine and n-hexylamine were, respec- dried over magnesium sulfate. Evaporation of the solvent gave 13.0 g. of crude product and after recrystallizatiop tively, 87, 70, 65 and 33%. Superficially it would from ligroin, 9.8 g. (72%) of p-nitrotoluene, m.p. 50-51 , appear that the reagent is satisfactory for oxidation was obtained. A mixture melting point with an authentic of t-carbinamines and dialkylmethylamines to the specimen showed no depression. corresponding nitroalkanes. This reaction un- Oxidation of p-Anisidine to p-Nitroanisole.-A peracetic acid solution in chloroform was prepared as described above. R~CHX'Hz+ RzCHNOH ----f RzCHNO+ RzCHNOz The oxidation of 12.3 g. (0.1 mole) of p-anisidine also was carried out as described above and 14.0 g. of crude product doubtedly proceeds through the intermediate hy- isolated. After recrystallization from ethanol there wy ob- droxylamine and nitrosoalkane. That this is indeed tained 12.5 g. (82%) of p-nitroanisole, m.p. 52.5 to 53 . A the case is indicated by the transitory blue color ob- mixture melting pomt with an authentic specimen showed served in all of these reactions. The fact that a no depression. Oxidation of 2-Amino-p-cymene to 2-Nitro-p-cymene.-In rather poor yield of nitroalkane is obtained from the usual manner there was obtained 18.5 g. of crude oxida- n-hexylamine may be explained by a relatively rapid tion product. This was dissolved in 100 ml. of methylene prototropic conversion of the nitrosoalkane inter- (5) N. Kornblum, R. J. Clutter and W. J Jones, ibid., 78, 4003 mediate to its stable tautomer, n-hexaldoxime. The (1956). ultimate fate of this , if indeed it was formed, (6) W. D. Emmons and A. S. Pagano, ibid., 77, 89 (1955). was not investigated but certainly this explanation (7) All preparations of peracetic acid were routinely carried out be- for the poor yield obtained with this primary hind a safety shield. For information concerning the hazards of 90% hydrogen peroxide see E. S. Shanley and F. P. Greenspan, Ind. Eng. (4) W. D. Emmons, THISJOURNAL, 76, 3470 (1954) Chem., 39, 1536 (1947). 5530 VOl. 79 chloride and the resulting solution was passed over a 2 X 5 tionation in a Todd column packed with glass helices. The cm. column of silica gel. The column was washed with a residue, still containing some solvent, was fractionated in a little solvent and the combined eluates were evaporated. spinning band column, and 40.2 g. (65y0)of 2-nitrobutane, There was obtained 12.8 g. of 2-nitro-p-cymeiie, b.p. 94" b.p. 64-66" (60 mm.), ~ZOD1.4043, obtained. The infrared (2.0 mm.), n% 1.5288. The infrared spectrum of this spectrum of this product was identical in ail respects to that product was identical in all respects to that of an authentic OF an authentic sample. sample. Reaction of Trifluoroperacetic Acid with n-Hexylamine.- Oxidation of Ethyl p-Aminobenzoate to Ethyl p-Nitro- =1 solution of trifluoroperacetic acid was prepared by drop- benzoate.-The reaction when carried out in the usual way wise addition of 60.5 ml. (0.36 mole) of trifluoroacetic an- gave 14.7 g. of crude product which after recrystallization hydride to a cooled suspension of 8.2 ml. (0.3 mole) of 90% from ethanol weighed 12.8 g. (667,) and melted at 53-55". hydrogen peroxide in 50 ml. of methylene chloride. This It showed no depression in melting point when mixed with solution was then added over a 30-minute period to a well- an authentic specimen of ethyl p nitrobenzoate. stirred suspension of 85 g. (0.8 mole) of anhydrous sodium Oxidation of sec-Butylamine to 2-Nitrobutane .-Hydrogen carbonate in 400 ml. of methylene chloride at -25' to -35". peroxide (65.2 ml., 2.4 moles) was added dropwise fairly At this temperature a solution of 5.0 g. (0.05 mole) of n- rapidly to 300 ml. of ice-cooled ethylene chloride with vig- hexylamine in 10 ml. of solvent was added dropwise, and the orous stirring. After addition of four drops of sulfuric acid resulting mixture was stirred at -30" for one hour. It catalyst 292 g. (2.88 moles) of acetic anhydride was added was then poured into 500 ml. of water. The organic layer to the cooled solution over a 90-minute period. The mix- was dried over magnesium sulfate and the volatile solvent ture so obtained was stirred 30 minutes at 0" and 30 minutes evaporated. There xas obtained 7.9 g. (80%) of n-hex)-1 at room temperature. It was diluted with 200 ml. of ethyl- trifluoroacetamide, b.p. 80' (1.0 mm.). The infrared ene chloride and heated rapidly to reflux. At this ternpera- spectrum wds typical of an S-substituted amide arid ture a solution of 43.8 g. (0.6 mole) of sec-butylamine in showed carbonyl bands at 1710 and 1550 cm.-'. 50 ml. of ethylene chloride was added dropwise over a one- Anal. Calcd. for CsHI:r';OF8: C, 48.72; H, 7.16; x, hour period. The reaction iws very exothermic during 7.10. Found: C, 48.76; H, 7.48; S,7.62. this addition and rapidly developed a blue color. After the amine addition was complete the mixture was heated Acknowledgment.-We are indebted to Mr. A. S. under reflux one hour. It was then cooled, washed with 2 Pagano for certain preliminary experiments in con- X 500 ml. of cold 1: 1 ammonia, and finally with 500 ml. of nection with this work. water. The organic extract was dried over magnesium sulfate, and the major portion of solvent removed by frac- HUNTSVILLE,ALABAMA

[CONTRIBUTION FROM THE INSTITUTE OF SCIENTIFIC AND INDUSTRIAL RESEARCH,OSAKA UNIVERSITY] The Curtius Rearrangement. I. The Decomposition of rn- and p-Substituted Benzazides in Toluene

BY YASUHIDE YUKAWA AND YUHO TSUNO RECEIVEDFEBRUARY 15, 1957 The rates of the Curtius rearrangement of various substituted betizazides in toluene were measured by collecting the nitro- gen evolved: the activation energies and log PZ were calculated. The rate differences attributable to substitution were sinall but the activation and log PZ varied over a wide range. The rate changes were, however, found to depend on the changes in activation energy. Electron-releasing groups in the m-position of berizazide increased the reaction rate and electron-attract- ing grcrups decreased it. On the other hand, all substituents in tne p-positinn decreased the rate. These results, ILhich differ from those reported for the Lossen, Hofmann and Schmidt rearrangements, are discussed in terms of the polar effects of the substituents and the effect of conjugation of the with the benzene ring on the breaking bond.

Although the Curtius rearrangement, * the decom- An azide decomposes to give a molecule of nitrogen position of acyl azide into an isocyanate and nitro- and an intermediate which contains a nitrogen gen, is an important procedure for replacing a car- atom with an incomplete octet, followed by intra- boxyl group by an amino group or amino deriva- molecular migration of R. In other words, the re- tives, few kinetic studies2v3have been reported. action in which loss of nitrogen occurs is the rate- The Curtius rearrangement has been thought to determining step. proceed through a mechanism4 analogous to those Sewman and ~o-workers,~in their kinetic study of similar rearrangements such as the Lossen, Hof- of this rearrangement, demonstrated that the mann and Schmidt rearrangements. Of the var- kinetics in various solvents was first order and that ious mechanisms5~6proposed, the following expres- no salt effect was present. However, kinetic sion has been considered to be a probable one. effects of structural changes in the azide, and R R effects of substituents on the migration of the \ +- \I + phenyl group in benzazide have not been investi- C--N=N=S --+ C=N + NP+ gated. The study made by Hauser and others'ss // / 0 -0 on the Lossen and Hofmann rearrangements in- R--N=C=O dicated that electron-releasing substituents in the (1) For a comprehensive review see, P. A. S. Smith, "Organic Re- migrating phenyl group increase and electron- actions," Vol. 111, John Wiley and Sons, Inc., New York, N. Y.,1949, attracting groups decrease the rate, the sequence p. 337. (2) C. W. Porter and L. Young, Tim JOURNAL, 60, 1497 (1938); being in accord with the polar effects of the respec- E. W. Barrett and C. W. Porter, ibid., 63, 3434 (1941). tive substituents, and the experimental results (3) XI. S. Sewman, S. H. Lee, Jr., and .4. B. Gattett, ibid., 69, 113 were found to follow Hammett's equation. In the (1947). (4) F. C. Whitmore, ibid., 64, 3274 (1932). (7) T. F. Bright and C. R. Hauser, THISJOURNAL, 61, 618 (1939): (5) C. R. Hauser and S. W. Kantor, ibid., 73, 4284 (1950). W. B. Renfrow, Jr., and C. R. Hauser, ibrd., 69, 2308 !1937). (6) J. Hine, "Physical Organic Chemistry," hlcGraw-Hill Book (8) C. R. Hauser and W. B. Renfrow, Jr., ibid., 69. 121 Co., Inc., New York, N. Y.,1956, pp. 319-320. (1937). 本文献由“学霸图书馆-文献云下载”收集自网络，仅供学习交流使用。

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