342
BERINGER, FALK, KARNIOL, LILLIEN,3 f A S U L L 0 , hfAUSNER
evaporated to dryness in vacuo to yield 6.0 g. (71%) of crude 3aitrodiphenyliodonium fluoride. This was recrystallized from a mixture of alcohol and ether to give a micro4 product of crystalline product, m.p. 120-124’ dec. . greater purity was obtained by shaking the bromide in aqueous suspension with excess silver oxide for 1-2 hr., followed by filtration and neutralization with 570 hydrofluoric acid. Evaporation to dryness in vacuo gave material of m.p. 143146” dec. 3-Nitro-4’-methoxydiphenylEther.--A solution of 1.O g . of p-rnethoxyphenol in 50 ml. of 0.1 ;1/1 sodium hydroxide was shaken with 1.95 g. (3.80 mmoles) of 3-nitro-4’-methoxydiphenyliodonium tosylate. The oil which formed was extracted with methylene chloride, and shaken with 5% sodium hydroxide and with uater. The solvent was evaporated and the residue flash distilled a t 1 m m . The fraction collected below 100” was identified as p-iodoanisole, 0.74 g. (83%). Above 150°, a yellow oil distilled which solidified on cooling. Recrystallization from aqueous methanol gave 0.53 g. (577,) of 3-nitro-4’-methoxydiphenyl ether, m .p. 73-74”. Anal. Calcd. for C13HllN04: C, 63.67; H , 4.52; S, 5.71. Found: C,63.81; H,4.61; N,5.56. 3,3’-Dinitrodiphenyl Ether.-A solution of 1.0 g. of mnitrophenol in 50 ml. of 0.1 A4 sodium hydroxide was shaken with 2.0 g. (3.9 mmoles) of 3-nitro-4’-methoxydiphenpliodonium tosylate. The oil which formed was extracted as described in the preparation of 3-nitro-4’-niethoxydiphenyl ether. Distillation at 1 mm. gave 0.85 g. (93%) of p-iodoanisole, and a t 150-200” there distilled an oil which crystallyzed a t room temperature. Recrystallization from aqueous ethanol gave pale yellow needles of 3,3’-dinitrodiphenyl ether, 0.54 g. (50%), m.p. 124-125’. Anal. Calcd. for C1?H&J”Oj: C, 55.49; H, 3.09; N, 10.77. Found: C, 55.60; H, 3.16; N, 10.71. Isolation of Products from Hydrolysis.-The products mere extracted continuously from aqueous solution with ether. Unreacted iodoniurn salt was precipitated from aqueous solution as the bromide. Phenols were separated from neutral products by shaking the ether extracts with 570 sodium hydroxide solution. The basic extracts were acidified and continuously extracted with ether. In initial runs, the ethrr was rvaporateti and the products in the rcsiduc
[CONTRIBUTIONFROM
Diaryliodonium Salts.
THE
IX.
AND
SOhlMER
Vol. 8 1
were separated by fractionation through a Holzmann column and identified as the pure compounds. In subsequent runs, the products were flash distilled at 1 mm., and the composition of the distillate was determined by means of infrared analysis. The ether extracts of neutral products were worked up in the same way as the acidic extracts; the products wcrc similarly identified by separation into the pure compounds and the composition was determined by infrared analysis. I n the case of 3-methyldiphenyliodonium tosylate the coniposition of the neutral products was found by the method of refractive indices. In the hydrolysis of 3-nitrodiphenyliodoniuni fluoride and 3-nitro-4’-methoxydiphenyliodoni~1m tosylate, the phenols were not equimolar with the iodo conipounds. Additional high boiling neutral products were observed which were identified from their infrared spectra a 5 diary1 ethers. Hydrolysis in the presence of fluoroboric or p-toluenesulfonic acids considerably reduced the a~nountof ether formation. The ethers from the hydrolysis of 3-nitro4’-methoxydiphenyl iodonium tosylate were identified as 3nitro-4’-methoxy- and 3,3’-dinitrodiphenyl ethers. Kinetic Experiments.-The water emplo>-edin the kinetic runs was doublpdistilled. The dioxane was purified according t o Fieserls; 9570 ethanol was fractionally distilled before use. Reagent grade chemicals, p-toluenesulfonic acid, cupric chloride and cuproin were used without further purification. Aqueous solvents mere prepared by tnixing equal volumes of water and the organic solvent (dioxane or ethanol) at 25’. Sodium p-toluenesulfonate solutions were prepared by neutralization of standard p-toluenesulfonic acid with standard sodium hydroxide, and then tlilution to the required volume. Ten-milliliter portions of a standard iodoniurn salt solution were sealed in Pyrex test-tubes and immersed in an oilbath maintained a t 100.1 i 0.05”. Tubes were withdrawn a t various intervals and cooled. The contents were titrated with 0.1 N sodium hydroxide from a 10-nil. niicroburet using brom cresol green-methyl red i~idicator.’~ (18) L. Fieser, “Experiments in Organic Chemistry,” second ed.,
D. C. R e a t h and Co., h-ew York, N. Y., 1941, p. 308. (19) I. bf. Kolthoff and E . B. Sandell, “Textbook of Quantitative Inorganic Analysis,” reviswl eel,, T h e LIacmillnn Co., New York, N. Y., 1913, p. 451. 1’ASADEYA, C A L I l ~ .
DEPARTMENT O F CHEMISTRY, POLYTECHNIC INSTITUTE
OF
BROOKLYX.]
The Synthesis of Substituted Diphenyliodonium Salts1
BY F.MARSIIALL BERINGER, ROBERT-1.FALK, MARILYN KARNOL,IRVING LILLIEN,GIULIOMASULLO, MARVIN MAUSNER AND ERWINSO~IMER RECEIVEDJULY 7, 1958 This paper reports the synthesis of numerous diphenyliodonium salts bearing nitro, 11 alogeno, methanesulfonyl, carboxyl alkyl, cycloalkyl, acetoxyl, acetamido, succinimido and methoxyl substituents.
The first paper2 of this series surveyed the synthesis of diphenyliodonium salts and reported improved methods. These methods have been used and extended in the present work to prepare diphenyliodonium salts bearing nitro, halogen^,^-^ (1) This paper is taken from t h e Ph.D. dissertations of Robert A Falk, Irving Lillien and Marvin Mausner a n d from t h e M.S. theses of Marilyn Karniol, Giulio Masnllo and Erwin Sommer; see also Acknowledgments. Irving Lillien was an Alfred P. Sloan Foundation Fellow, 1956-1959. (2) F. M. Beringer, M. Drerler. E. M , Gindler and C. C . Lumpkin, THISJOURNAL, 75, 2705 (1953). (3) C. Willgerodt and E . H. Wikander, Ber., 40, 4066 (1907). (4) I.. W. Wilkinson, ibid., 28, 99 (1895). ( 5 ) F. G. Benedict, Dissertation, Heidelberg, 1896; see C. Willgerodt “Die organischen Verbindungen mit mehrwertigen Jod,” F. Enke, Stuttgart, Germany, 1914, p. 192. (6) C. Willgerodt and G. McP. Smith, Ber., 3 1 , 1311 (190-4). (7) C. Willgerodt and P. Lewino, J. punkr. Chem., 69, 321 (1904).
methanesulfonyl, carboxyl, cycloalkyl acetoxy, acetarnido, 1 3 , 1 4 succinimido and methO X ~ ~substituents. ~ J ~ The methods are listed below and then discussed in connection with the experimental results. (A) Coupling of two aromatic compounds with iodyl sulfate in sulfuric acid (Table I) (8) J. McCrar, Ber., 28, 97 (1895). (9) H. Peters, J . Chem. Soc., 81, 1350 (1902). ( I O ) C. Willgerodt and H. Rogratz, J. p r a k t . Chem., 61, 423 (1900). (11) P. Willgerodt and E. Rampacher, Ber., 34, 3666 (1901). (12) C. Willgerodt and T. Umhach, Ann., 327, 2139 (1903). (13) C. Willgerodt and W. Xageli, Ber., 40, 4070 (1907). (14) H. Abbes, ibid., 28, 84 (1895). (15) R . A. Mastropaolo, A n d e s asoc. guim. Argentina, 28, 101 (1940); C. A , , 35, 734 (1941). (16) R. B. Sandin, M. Kulka and R. RfcCready, Tars J O U R N A L , 6 8 , 157 (1936).
343
SUBSTITUTED DIPHENYLIODONIIJM SALTS
Jan. 20, 1959
TABLE I SYMMETRICAL DIPHENYLIODONIUM SALTSBY REACTION A"qb Substituents
Anion
%
Solvent
M.P., "C.
T,
Ea.
O C .
Ref.
(hr.)
2 *C 72 F 5-10 (2) ...... 208-209 c 0-5 ( l ) , 20 (21) 65d G Methanol 209 2* 10 (2), 20 (144) 25 F Water 165-167' 2*, v 42 178-179 V 10 (a), 20 (144) F 39 Methanol 193-194e 24 Water-DMF 217" Exptl. F 54 Methanol 10 ( 2 ~ 2 0(241, 194-199 V, exptl. 45 (36) 17 ...... 177-1 78 2* F 5-10 (8), 20 (15) 53 Methanol 154-156' 5-10 (l), 20 (45) 65d G Methanol 232-233 84d Methanol 226-227 18, exptl. 60 G 5 ( l ) , 20 (12) Methanol 190 4, V,exptl. 7 Acetonitrile, then D h l F 211f 45 (2) F 91 15 (2), 20 (48) 4, v Methanol 204-205 15 (2), 20 (48) 68 F 4, v Methanol 171 5, v 62d G Ethanol-ether 203 5 (I), 20 (24) lgd DMF-methanol 208" 71d*" G Formic acid-acetic acid 5 (11, 20 (68) 198-199 46 F . .... 211-214 5 (31, 20 (33) 7 ...... 206 32 F Both: 5 (1) Water 152-1 53 20 (24), 50 (3) 34 G 153-155 Water the yields are ada Headings of Tables I-V: Salts paired with braces were obtained from the same reaction mixture; ditive. The heading Ref. signifies another source of information on this material-Tables (Roman numerals), footnotes in text (arabic numerals), footnote in same table (small letter), Experimental section (Exptl.). The asterisk signifies that the data are those of the reference and are included for comparison. Each melting point is the highest observed for the salt prepared in this way and may be crude or, if solvent is given, for recrystallized material; solvent abbreviations: D M F (dimethylformamide), DMS (dimethyl sulfoxide). Yields are calculated on unrecrystallized material unless otherwise specified. The heading Eq. refers to a relevant preparative equation in text. Ratio refers to the mole ratio of reactants and is specifically defined in other tables. Reaction conditions are those for the condensation reaction; temperatures are followed M.p. of 210' reported See equation in text and details in Experimental section. by the number of hours, in parentheses. Yield after one crystallization. e M.p.'s reported by M. 0. Forster and J. H. Schaeppi, J . Chem. Soc., 101, 382 (1912). (ref. 3): HSOl-, 168.5'; C1-, 214". I-, 130.5". f Anal. Calcd. for C12HoIN~0&3:C, 30.78; H , 1.93; N, 5.98; S, 6.85; H + , 0.213. Found: C, 30.57; H, 5.08; N, 5.58; S, 6.72; H + , 0.210. 0 This m.p. was obtained by recrystallization of material of m.p. 120' previously reported (ref. 2). Anal. Calcd. for C12HsClFZI: C1-, 10.0. Found: C1-, 9.81; ' Anal. Calcd. for C12H8BrF21: Br-, 20.2. Found: Br-, 20.0. j M.p.'s reported (ref. 4): C1-, 202'; Br-, 190"; I-, 163 . Anal. Anal. Calcd. for C1B8Br2ClI: C1-, Calcd. for CI2HgBr2IO4S:neut. equiv., 536. Found: neut. equiv., 535 andd36. 7.50. Found: C1-, 7.46. " M.p.'s reported (ref. 5): C1-, 209'; Br-, 194 ; I-, 160'. Anal. Calcd. for CI2H8BrI3: Br-, 13.0. Found: Br-, 12.8 and 13.1. p-Diiodobenzene, m.p. and mixed m.p. 130°, also formed (16%). p Anal. Calcd. for QOH&lIO&: C1-, 7.08. Found: C1-, 6.96 and 7.04.
None
Br
f
.
.
.
.
.
*
4ArH
+ (1O)zSOa + 3H~S04-+2ArzI+
(A)
(B) Coupling of two aromatic compounds with an iodate in acetic acid-acetic anhydridesulfuric acid (Table 11) 2ArH
+ IO3- f 2H2S04+ 2Ac20 -+ ArJ+ + 2HS04- + 4AcOH + [O]
(B)
(C) Coupling of two aromatic compounds with an iodine(II1) acylate in the presence of an acid (Table 111)l7 0
2ArH
0
/I I/ + I(OCR)3 + H X -+- ArzI+X- + 3RCOH
(C)
(D) Condensation of an iodoso compound, an iodoso diacetate or an iodoxy compound with another aromatic compound in the presence of an acid (Table IV) l7 ArIO
+ Ar'H + HzSOl +
ArI +Ar' HOSO3-
ArI(OAc)z
+ Ar'H + H z S O ~+
ArI+Ar'HOS03-
+ HzO
+ 2AcOH
+ Ar'H +ArI+Ar' FICCOOH + FlCC03- + 2AcOH ArIOz f Ar'H + HzS04 ArI+Ar' HOSO3- + HzO + [O] ArI(OAc)2
+ 2H30' + 4HS04-
(D-1) (D-2)
(17) These methods recently have been used to prepare 2,2'-dithienyliodonium and phenyl-2-thienyliodonium salts: F. M. Beringer, H. E. Bachofner, R. A . Falk and M. Leff, THIS JOURNAL, 80, 4279 (1958).
(D-3)
--f
(D-4)
I n some cases i t has been possible to oxidize an iodo compound in situ and then to condense i t with another aromatic compound (Table IV). ArI
oxidation
Ar'H
ArI+Ar' HOSO3-
P
HzSOa
(D-5)
Reaction A,-Masson and co-workers,l8 who first used reaction A, reported that iodyl sulfate could be prepared either by the thermal decomposition of iodine pentoxide in sulfuric acid or by interaction of iodine pentoxide in sulfuric acid 212
f 3120s + 5HzS04 ----f
5(IO)zSOa
+ 5Hz0
(E)
while later Beringer and co-workers2 used iodine with an iodate. While this last reaction has been 212
+ 6NaI03 + 11H2SO4
----f
5(10)2S04
+ 6NaHS04 + 8 H 2 0
(F)
frequently used in the present work, i t also has been found that iodine in sulfuric acid may be (18) I. Masson, Nature, 139, 150 (1937): I. Masson and E. Race, J . Chem. Soc., 1718 (1937); I. Masson and W. E. Hanby. ibid., 1699 (1937); I. Masson and C. Argument, i b i d . , 1702 (1938).
344
LILLIEN,hfASULLO,
E E R J N G B R , F A L K , I(AKNIOI,,
Vol. 81
R I A U S N E R A N D SOSIMYIER
TABLE 11 SYMMETRICAL DIPHENYLIODONIUM SALTS BY REACTION Banb Substituents
None
4,4'- (CIia)a
Anion
M.p., "C.
Solvent
7%
Iiefertuces
c1 €IS04 NO3 C1 Ur
228-229 167-169" 149-1 51 1DO-191d
Methanol Methanol Water Methanol Methanol Methanol-water Methanol Methanol
63
20 * 22, exptl. 21,* V 2, 8, 9, I, exptl. 2,8, 111, exptl. 2, 8, 111, exptl. 2, 8, 9, I, exptl. 2, 8, 9, I , exptl. 10, v 11, exptl., I
I
c1'
2,2',4,4',6,6'-(CH,), 4,4'-(t-B~ty1)2
c1" Br' I Br' I' Br"" I Br I Br
4,4'-(~-Clz~~23)2
4,4 '-D icyclohexyl 4,4'-(CH30)2 4,4'-(CH3CONH)z
.,.'-(5
O\C---CH2 'C-CHZ I
)
I" c1*
1i1-17Zdo
171-173d~" 163 1F2- 1G3d58 1468 195< , 184-185' dae
...... Acetone Acetone Acetone Acetone Acetone Acetone Acetoue Methanol Methanol bI ethanol
161; 93-96 99-103 175 159-1 GO 202
190" 215" 173'
......
51 63 39 5tj 00 53 64 3; 38 35 32 37 42 35 38 9 9 20 48
11
V 2,15, V 13
2*, 13, 14
Formic acid 44 Exptl. Formic acid88 Exptl. 2 acetic acid See equation in text and details in Experimental section; For explanation of column headings see Table I, footnote a. e M.p. of 153-154" reported (ref. 22). M.p.'s reported: C1-: 178' (ref. 8), 193" (ref. 9); Br-: 178" (ref. 8), 205-207 Runs by independent (ref. 2 ) ; I-: 143-156', depending on the rate of heating (ref. 9), 146" (ref. S), 172-174" (ref. 2). workers; previously reported m.p.'s (ref. 2), now believed incorrect. f Anel. Calcd. for C18H22ClI: C1-, 8.85. Found: Anal. Calcd. for CZOH&~I:C1-, 8.3. Found: C1-, 8.3. ' M.p.'S reC1-, 8.89. M.p. of 146' reported (ref. 10). ported (ref. 11): C1-, 157'; Br-, 144'; I-, 142'. i Anal. Calcd. for CzJIz~BrI: C, 50.76; H, 5.54. Found: c , 50.49; H, 5.75. Anal. Calcd. for Ca6H68BrI: Br-, 11.46. Found: Br-, 11.70. Anal. Calcd. for C3&&: I-, 17.04. Found: I-, 17.16. nz Anal. Calcd. for CZ4HsoBrI:C, 54.87; H, 5.76; Br-, 15.2. Found: C, 54.83; H, 5.77; Br-, 15.1. lL M.p.'s reported: 179-182' (ref. 2 ) , 180' (ref. 15). Satisfactory analysis reported (ref. 2). p M.p.'s reported: Br.-, 165' (ref. 1 3 ) ; I-, 176.5" (ref. 13) and 173" (ref. 14). q Anal. Calcd. for C2(,H~~ClI?;20~: C, 47.03; H, 3.16; h', 5.48; C1-, 6.91. Found: C, 46.88; H, 3.37; N, 5 . 5 i ; C1-, 6.85. I
207 184-185
TABLE I11 C" SYMMETRICAL DIPHBSYLIODONIUM SALTSBY REACTIOX Substituents
Anion
i\Z.p., ' C .
7%
Solvent
HX HX/I+3
'
I', O C . (hr.)
Kef.
CFaC02 134-130 Benzene 49 3 . ~ - I~O t o o (121, 20 (3) V, exptl. 3.3d -15 to 0 (12), 20 (3) Benzene 36 CZFSCOZ 144-145 3.3d -15 t o 0 (12), 20 (3) Benzene 31 * CaF,CO, 148-151 Dioxane 11 CI18COe 190-191 3.5d 0 (16), 25 (4) 4,4'-(CHdz Rr 206-211' Water, methanol 58 1.25d -10 to 25 (12) 2,I1 4,4'-(CHaC02)2 C1' 239-241 Methanol 15 1 . 2 j d -15 t o 0 (12), 20 (48) V The The column headings have the same meanings as in Table I ( q . v . ) . See also footnotes to individual headings. iodine(II1) acylate and the catalyzing acid contain the same acylate group as the salt isolated. Iodine(II1) trifluoroacetate The mole ratio of catalyzing acid to iodine(II1) acylate. a A sample crystallized from was used with sulfuric acid. water had a m.p. of about 170°, close to values in Table 11. However, more thorough drying and/or recrystallization from methanol raised the m.p. to 206-211', in agreement with the value of 205-207" reported in ref. 2. This may be a case of polymorphism. See, however, the discussion under Melting Points in the ExperimenCdl section. f Anal. Calcd. for C16H,40JC1: C, 44.41; H, 3.26. Found: C, 44.47; H , 3.39. 4,4'-(CHaO)z
(I
conveniently oxidized to iodyl sulfate with nitric acid. 12
+ 3HNOs + 8HzS04 --+
( I O ) ~ S O+~ 3 ~ 0 + + 4 H 3 0 ++ 7
~
~
0 ~ (G)
In the present work symmetrical iodonium salts were prepared by reaction A from benzene, the halogenobenzenes, nitrobenzene, p-nitroanisole and rnethyl +tolyl sulfone (Table I). The yields were over 5070 except with the last compound. The structures and purities of the products and the formation of isomers wi!l be discussed after the presentation of the various synthetic methods. As reaction A was initially rapid and exothermic, addition of the aromatic compound to the iodyl
-
sulfate suspension was best done with cooling a t about 5". The first phase of the reaction may correspond to the conversion of the aromatic compound to the conjugate acid of an iodoso 2 h H 4- (I0)2SOa 4- H2SO4 --j 2ArI +OH
+ 2HS04-
(H)
compound. The slower second phase of the reaction corresponds to the formation' of the diaryliodoniu1n cation. ArH
+ ArI+OH --+
ArSI+
+ HzO
(1)
It has been reported that various mono-, di- and trialkylbenzenes have been coupled to give iodonium salts by this procedure when various amounts
SUBSTITUTED DIPHENYLIODONIUM SALTS
Jan. 20, 1959
345
of water were added to the suspension of iodyl yield of 4-nitrodiphenyliodonium salts was obtained. It was found that this same reaction could sulfate in sulfuric acid.l9 Reaction B.-Benzene, alkylbenzenes, lga acetani- be run with 4-nitroiodoxybenzene instead of the lide and succinanil were coupled to symmetrical iodoso compound. Here it may be that the iodonium salts with an iodate in acetic acid-acetic iodoxy compound was reduced to the iodoso comanhydride-sulfuric acid (Table 11). The reaction pound, which then coupled. with anisole went in poor yield and was not reguIn most of the above cases the iodoso (or iodoxy) larly reproducible; see reaction C below. lQb Though compounds were first prepared from iodo comboth reactions A and B could be used with benzene, pounds via the dichlorides. In some cases a B was the more satisfactory for the isolation of the Clz NaOI1 ArI -+ ArIClz ArIO useful soluble salts, such as the chloride,2~20 nitrate21 and bisulfate.22 NaOC1 If the temperature of a reaction mixture was + ArIOz (L) not kept below 15" during the addition of the sulfuric acid and for some hours thereafter, a vigorous, convenient short-cut was to oxidize the iodo exothermic reaction might occur. It may be that compound in situ to an iodoso or iodoxy compound, in such instances the iodate was effecting a deep- which could then undergo the coupling reaction. Barium peroxide and potassium persulfate were seated oxidation of the aromatic compound. Reaction C.-This reaction is closely related to successful oxidants. While no intermediates were reaction B and involves the symmetrical coupling isolated, the oxidations to iodoso compounds may of two reactive aromatic compounds with an iodine- be (111) acylate and an added acid.17 While anisole ArI BaO2 3H2S04-+ ArI(OSO3H)Z 2H2O Bas04 (M) yielded a product with iodine(II1) acetate and acetic acid, most work has been done with iodine- ArI K2S2084- 2H2SO4 + ArI(OSOaH)~ 2KHSOI (N) (111) trifluoroacetate. This reaction makes readily While this work was in progress, Sandin and coavailable 4,4'-dimethoxydiphenyliodonium salts, recently used in the synthesis of t h y r o x i ~ i e . ~workersz4 ~ ~ ~ ~ ~ reported a similar oxidation (with perWhile in this case added trifluoroacetic acid was acetic acid) and condensation of iodaryl compounds where n ranged added to allow the reaction to proceed a t a useful (of the type 2-IC6H4(CH2)nC~H6, rate, with less reactive compounds, such as toluene, from 0 to 3) to give cyclic iodonium salts. Salts Prepared by Metathesis.-From the salts a stronger acid such as sulfuric acid was needed; see prepared by condensation reactions others were Table 111. Results to date do not distinguish between the prepared by metathesis and are reported in Table V. protonated iodine(II1) acylate and the related As the solubility of the iodonium halides in water decreases with increasing atomic number of the iodonium ion as the effective electrophilic species. halide ion, the bromide and iodide salts easily could 0 OH 0 0 be prepared from the chloride.2f20 Other salts prepared in the same way from the chloride are the picratej2 perchlorate,26 tetraphenylborate2e HX xRCOzH Xand 2,4,6-tribroinobenzenesulfonate. 27 Diphenyliodonium benzenesulfonateZ8and tosyReaction D.-This reaction comprises various condensations of an iodoso compound or an iodoxy late28a29and 4-nitrodiphenyliodonium tosylate, , ~ ~ ~pre~~ compound with another aromatic compound in convenient for studies of s o l v o l y ~ i s were pared by metathesis of iodonium halides with the the presence of an added acid; see Table IV. In general, when the iodoso compound had elec- soluble lead salts of the sulfonic acids. A similar tron-withdrawing groups, the reaction proceeded metathesis with silver fluoroborate give the presatisfactorily in sulfuric acid, while if electron- viously reported diphenyliodonium f l u o r ~ b o r a t e ~ ~ releasing groups were present in either reactant, and with silver nitrate gave the nitrates. Structures of the Iodonium Salts.-The structhe reaction proceeded better in acetic acid-acetic tures of many iodinium salts have been proved by anhydride-sulfuric acid. Condensations with anisole and with thiophenell were catalyzed with the thermal decomposition of iodide salts to iodo compounds.2f20I n the present work the only trifluoroacetic acid. heat A difficult condensation to effect was that of 4Ar*I+I2ArI (0) nitroiodoso-benzene with benzene. As previously (24) J. D. Collette, D. McGreer, R . Crawford. F. Chubb and R . B. reported, all early attempts gave the reduction Sandin, THISJOURNAL, 78, 3819 (t956). product, 4-nitroiodobenzene. However, by run(25) E. R. Kline and C. A. Kraus, i b i d . , 69, 814 (1947). (26) (a) G. Wittig and K . Clauss, Ann., 578, 136 (1952); (b) Walter ning the reaction between -30 and -20") a 43% ____f
L
+ +
+
+
+
+
+
+ +
+
(19) (a) D. A. Berry, R . W. Greenlee, W. C. Ellis and Ihl M. Baldwin, Twelfth International Congress of Pure and Applied Chemistry, New York City, September, 1951; Abstracts of Papers, p. 465. (b) The reaction of anisole with iodyl sulfate in acetic acid has been recently reported: J. T. Plati, U. S. Patent 2,839,583 (June 17, 1958). (20) F. M. Beringer, E. J. Geering, I. Kuntz and M . Mausner, J . Phys. Chem., 60, 141 (1956). (21) F. M. Beringer and E . M . Gindler, T a m JOURNAL, 77, 3203 (1955). (22) C. IIarlinnn a n d V. hfcyer. B r r . , 27, 1592 (1894). (23) G . Ilillmann, Z . Nwurforsch, l l b , 419 (1956).
Maier, B.S. Thesis, Polytechnic Institute of Brooklyn, 1956. (27) Thomas Maggio, B.S. Thesis, Polytechnic Institute of Brooklyn, 1956. (28) Morris Rapoport. M.S. Thesis, Polytechnic Institute of Brooklyn, 1958. (29) Irving Kuntz, Ph.D. Dissertation, Polytechnic Institute of Brooklyn. 1955; see also accompanying papers: F. M. Beringer, E. M. Gindler, M.Rapoport and R. J. Taylor, THISJ O U R N A L , 81, 351 (1959); M. Caserio, D. L. Glusker and J. D. Roberts, ibid., 81, 336 (1959). (30) L. G. Makarova and A. N. Nrsmeyaaov, Buli. acnd. sci,, L'.S.S.K., Closse sci c h i i w . , 017 (1945); C. A , . 40, 4086 (19lii).
TAIILE
Iv
USSYMMETRICAL ~ I P H E h ' Y L I O D O h ' I U M S A L T S BY VARIATIOSS OF
s-
Suhst.~
13r
N(JlW
2-502
Ur" Br I Br
3-r\;0*
I I Bre
'I-"?:
208 207 16l-lt;2 144-145 143 150-151' 102 172-175" 172-175" 197-108 181-182 130h 145-146' 149 127-128 149-150
143-146 Ik 140-142 Ii 151-152 1i 155-160 i 88 143 153 Brk Brk 164' Brk 169 Br" 161'' nrVfL 175 118 (1 107 Br" Bro 18OP 176-177 Bre,' Br' 175 185' Urr 191-198" 1 168-1G93 CFaCOz 164-166 160-lG2 I 155-157 lir 188-189" 1' 1G-3 1"
2-C00I-I 3-COOH 4-COO13 4-F 2-c1 3-C1 4-C1 3-Br 4-Br 2-CI-13 3-CH3 4-CH3q 2-CII30 4-CHsO
4-CH3O
3-CH3C0S1-1 4-CHaCOKH'
3-502-4'CHaCOXlI
1
I"
Solverit
x p . , oc.
172-173
. . . .
il'atcr-acetic acid Methnnol
...... LiTater Methaiiol ..... Water Water LVater
...... ......
1)MF-rnethatlol ......
...... ...... . .,.. ......
\Vatcr-iiictliaiio1 Methanol ......
...... Formic acid Formic acid Formic acid ......
..... ...... \\:ater Water Water Water U-ater Methanol DFM-nicthatiol Benzenc Benzcuc Methanol ...... ..... .
.
.
70
74 54 ci0 10
--( a
01 79 62 96 98 58 19 78 41 > 24 12 53 39 55 69 27 12
-
3-1. 02 50 25 43 1.4 40 52 58 51 72 51
Eq.O
la 4s 1s
0-10 (I), 20 (24)
Is
2 2.1 5s, s 1 2 . 5 Is 2 la 1.8 Is 2 5s,h,I 12.5 5s,51 12.5 5 ~&I , 6.25 1s 2
2
0-10 (3) 0-5 ( l ) , 20 (4)
Ref.
2"
v v
5 (l), 20 (3) 0-5 (l), 20 (4) 20 (2) 20 (3) 20 (2) 20 (3) 10 ( l ) , 20 (1) 10 ( l ) ,20 (1) -20 to -10 (I), 0 (3) -30 (l), 0 (1)
2,*
v
v,
cxptl.
-20 (0.5), 0 (1)
v
v
2,* 2,* Y
v v
v
2, 3, v 2, 3,V v, cxptl. v, exptl. V
6s, N js, N 5s, N
5s, 1s
N
1s 1s 1s
Is 1s
57 40 28 20
la la la la la la la 3t la 5s, ILI la 5s
52
5s, N
83 92
OC. (Iir.)
6.2 8 2.1
Is
4s
I
