Aryne chemistry. Part XXXVI. Approaches to the synthesis of 5,6,7,8-tetrahalogeno-1,4-dihydro-2-nitroso-1,4-ethenonaphthalenes (2-nitrosotetrahalogenobenzobarrelenes)

摘要

1974 2695Aryne Chemistry. Part XXXVL1 Approaches to the Synthesis of 5,6,7,8-Tetrahalogeno-l,4-dihydro-2-nitroso-1,4-ethenonaphthalenes (2-Nitroso-tetra halogeno benzo barrelenes)By P. Christopher Buxton, Harry Heaney," Kenneth G. Mason, and John M. Sketchley, Department ofThe reactions of arynes, generated by aprotic diazotisation of the corresponding anthranilic acids, with nitroso-arenes gave N- hydroxycarbazole derivatives. 1.4- Dihydro-2-nitroso-1.4-ethenonaphthalene derivatives wereimplicated in reactions of 3-brorno-3.4-dihydro-1,4-ethenonaphthalen-2(1 H ) -one oximes with triethylamine,which led to the expected naphthalene derivatives.Chemistry, The University of Technology, Loughborough, Leicestershire LE11 3TUDURING earlier work2 we showed that the aproticdiazotisation of tetrabromoanthranilic acid in certainalkylbenzenes led to the formation of alkyltetrabromo-naphthalenes.Thus, for example, in the presence oftoluene we obtained 1,2,3,4-tetrabromo-6-methylnaph-thalene (2) in addition to the expected products. Itwas also shown that the naphthalene (2) arose from5,6,7,8-tetrabromo-l,4-dihydro-2-methyl-1,4-etheno-naphthalene (2-methyltetrabromobenzobarrelene) (1).The conversion of benzobarrelene derivatives intonaphthalenes by retro-Diels-Alder reactions is wellknown,3 but these reactions normally proceed only attemperatures around 400". Furthermore the acetylenewhich is lost preferentially is normally the most sub-stituted. We tentatively suggested a mechanism in-volving attack by the nitrosonium ion and formation ofa nitrosobenzobarrelene.2We have now verified the involvement of the nitro-sonium ion by obtaining low yields of the naphthalene(2) from the benzobarrelene derivative (1) in the presenceof various nitrosating agents (Scheme 1).Whereas thedecomposition of the benzobarrelene (1) was onlycomplete after ca. 3 days when pentyl nitrite was usedat 80deg;, when we used nitrosyl chloride reaction wasrapid, and with trifluoroacetyl nitrite reaction wasinstantaneous at room temperature. The yield of thenaphthalene (2) varied from 4 to 17 and was lowestwhen the most powerful nitrosating agent was used.Although the naphthalene derivatives were isolatedwithout difficulty, none of the other products wereidentified.They were very polar4 and could not beresolved by t.1.c.The disproportionation reaction was not observedwith the parent tetrahalogenobenzobarrelenes or with,for example, the adduct of tetrabromobenzyne with 9-xylene. This suggested that the attack on a disub-stituted double bond required the presence of an alkylgroup (or alkyl groups) on the homoconjugated doublebond in order to stabilise the cationic centre (Scheme 1).The formation of similar cations, as a result of homo-conjugation in benzobarellenes, has been suggestedPart XXXV, H. Heaney and S. V. Ley, preceding paper.H. Heaney, K. G. Mason, and J. M. Sketchley, J . Chem. SOC.( C ) , 1971, 567.J. P. N. Brewer, I. F. Eckhard, H. Heaney, and B. A. Mar-ples, J . Chem. SOC.( C ) , 1968, 664; H. Heaney and J. M. Jab-lonski, ibid.. p. 1895.Cf. S. J. Dominianni and P. V. Demarco, J . Org. Chem., 1971,36, 2534.previously.6 The stabilisation of the carbocation ispresumably sufficient to allow some proton loss ratherthan complete scavenging by nucleophiles. Deproton-ation of the carbocation would give a nitrosobenzo-barrelene, which would afford the naphthalene andnitrosoacetylene. Unsaturated nitroso-compounds,X AI ( 1 ) R =Me,X=BrNO9X X( 2 ) R = Me, X = B rSCHEME 1other than nitrosoarenes, are not well known6 and asfar as we are aware l-nitrosohex-l-yne and 3,3-dimethyl-l-nitrosobut-l-yne are the only examples of their typeto be well e~tablished.~We studied two approaches to the synthesis of 2-nitrosobenzobarrelenes. The cycloaddition reaction ofbenzyne with nitrosobenzene has been reported to affordN-phenylcarbazole.8 However, many reactions of thetetrahalogenobenzynes with substituted arenes result incycloaddition to the arene r e ~ i d u e .~ It was hoped thatthe presence of electron-releasing substituents on thearene residue would facilitate such cycloadditions. Wecarried out a number of reactions of nitrosoarenes withboth tetrabromo- and tetrachloro-benzyne and in eachI. N. Vorozhtsov, E. I. Berus, B. G. Derendyaev, and V. A.Barkhash, J . Gen. Chem. ( U . S . S . R . ) , 1969, 39, 2264; T. P.Lobanova, E. I. Berus, and V. A. Barkhash, ibid., p. 2269;T. P. Lobanova, N. M. Slyn'Ko, B. G. Derendyaev, and V. A.Barkhash, J .Org. Chem. (U.S.S.R.), 1971, 7, 2485.6 H. Feuer, ' The Chemistry of the Nitro and Nitroso Groups,'ed. S. Patai, Interscience, New York, 1969.E. Robson, J. M. Tedder, and D. J. Woodcock, J . Chem.SOC. ( C ) , 1968, 1324.G. W. Steinhoff and H. C. Henry, J . Org. Chem., 1964, 29,2808.H. Heaney, Fortschr. Chem. Forsch., 1970, 16 (l), 352696 J.C.S. Perkin Icase we isolated the corresponding iV-hydroxycarbazole(Scheme 2). In the previous report of the reaction ofnaphthalene derivatives (14) and (15) in 38 and 470,;yields, respectively.These results clearly implicate the intermediacy ofX NO (R*) nitrosobenzobarrelene derivatives. But nitrosoacetylene+ O R 3 - x amp; - n R 1 has remained undetected even in the presence ofthebaine, which is well known as a good substrate bothfor conventional dienophiles and for C-nitroso-com-OH pounds.12 Thus the presence of electron-withdrawing2-substituents in benzobarrelene derivatives leads totheir ready fragmentation., R2 x bsol; R2 X bsol;X R' x I R3( 3 ) x = H, ~1~ ~2 = ~3 = H(4) x = CI, RI = R2 = R3 = HSCHEME 2benzyne with nitrosobenzene the benzyne was generatedfrom benzothiadiazole 1, l-dioxide.We generated thearynes from arenediazonium-2-carboxylates and alsoobtained X-hydroxycarbazole (3) in very low yield fromthe reaction of benzyne with nitrosobenzene. Theisolated yields of N-hydroxycarbazoles in reactions withtetrahalogenobenzynes ranged from 9 to 30. Nonaphthalene derivatives were detected. No productswere isolated from an attempted reaction between tetra-chlorobenzyne and nitrosomesitylene.The structuresof the AT-hydroxycarbazoles (4)-(9) were proved byelemental analysis and spectroscopic methods, and in thecase of the compound (5) by conversion into the N-methoxy-derivative.The second approach to the preparation of nitroso-benzobarrelenes involved the dehydrobromination ofa-bromo-oximes. l-Nitrosocyclohexene has recentlybeen prepared in this way from 2-chlorocyclohexanone.10We were unable to brominate tetrabromo- or tetra-chloro-benzobarrelenone with either AT-bromosuccinimideEXPERIMENTALThe general methods used are given in ref. 11.Reactions of 5,6,7,8-Tetrabromo-1,4-dihyd~o-2-methyZ-1,4-ethenonaphthalene (1) with Nitrosating Agents.-(a) Pentylnitrite.The ethenonaphthalene (1) (500 iiig) and pentylnitrite (1 ml) were dissolved in benzene (10 nil) and stirredat 60", and acetic acid ( 5 drops) was added. After 16 11t.1.c. indicated the presence of starting material, and morepentyl nitrite (1 ml) and acetic acid ( 5 drops) were added.The reaction was monitored by t.1.c. and after 3 days nostarting material was detected. The solution was washedwith aqueous sodium hydrogen carbonate, dried, andevaporated. The residue was placed on a column of silicagel; elution with light petroleum gave 1,2,3,4-tetrabromo-6-methylnaphthalene (2) (80 nig, 2704), 1n.p. and mixed1ii.p. 120-122" (lit.,2 121deg;), identical (i.r., u.v., and lHn.m.r. spectra) with authentic niateriaL2 Further elutionwith more polar solvents gave unidentified oils.(b) Nitrosyl chloride.The ethenonaphthalene (1) (50nig) in carbon tetrachloride (30 nil) was treated withnitrosyl chloride (ca. 0.1 g) and the solution was stirred a troom temperature for 30 h. Conventional work-up andpreparative layer chromatography gave 1,2,3,4-tetrabronio-6-methylnaphthalene (2) (4 mg, 8), identical with thematerial described in (a).The ethenonaphthalene ( 1)(500 mg) was dissolved in carbon tetrachloride (10 ml) atroom temperature and trifluoroacetyl nitrite (200 mg) wasadded. An instantaneous green colour was produced and(c) Tri,fluoroacetyl n i t ~ i t e . 1 ~(10) R1=H, R2=Me(11 1 R1=OMe,R2 = H(12) R1 = HI R2=Me(13) R1= OMe,R2=H( 1 4 ) R1 = H,R2=Me(15) R1 = OMe, R2=HSCHEME 3 Reagents : i, HONH,+Cl-; ii, Et,N-Me,NCHOor dimethyl dibromohydantoin.However, 3-bromo- the solvent was removed. The residue was triturated with5,6,7,8-tetrahalogeno-3,4-dihydro-l,4-ethenonaphthalen- light petroleum and the insoluble material was removed.2( 1H)-one derivatives are available from the reactions of Preparative layer chromatography gave 1 2,3,4-tetrabromo-tetrahalogenobenzynes with suitable 2-bromoanisole 6-methYlnaPhthalene (2), identical with the materialderivatives.11 The ketones (10) and (11) were con-verted into the comesPonding Oximes (12) and ( 1 3 ) 9described in (a) (19 mg, 4). The fraction insoluble inlight petroleum showed almost no lH n.m.r. absorption, andpetroleum-soluble fraction were unsuccessful^benzyne with nitrosobenzene.Tetrabromoanthranilic acidattempts to isolate further products from the light- which were heated a t ca. 100" in dimethylformamidein the presence Of triethylamine and aff Orded the Reactions of Arynes with Nitrosoarenes.-(a) Tetrabromo-l2 P. Horsewood and G. W. Kirby, Chem. Comm., 1971, 1139.l3 D. E. Rice and G. H. Crawford, J . Org. Chem., 1963,28, 872.lo G. Just and W. Zehetner, Chem. Comm., 1971, 81.l1 P. C. Buxton, N. J. Hales, B. Hankinson, H. Heaney, S. V.Ley, and R. P. Sharma, J.C.S. Perkin I , 1974, 26811974 2697(4.5ti g, 0.01 mol) in acetonitrile (170 nil) was addcd con-currently with a solution of pentyl nitrite (1.36 nil, 0.01 mol)in acetonitrile (170 ml), during 45 min, to a solution ofnitrosobenzene (4.3 g, 0.04 mol) in acetonitrile (50 ml)which was maintained at 50-55". The stirred solutionwas maintained a t 50-55" for a further 45 niin, thesolvent was removed, and the residue was placed on acolumn of neutral alumina (activity I; 100 g).Elutionwith benzene-light petroleum (1 : 1) gave (a) azoxybenzene(220 mg) and (b) nitrosobenzene (420 mg). Elution withbenzene gave, as a pale yellow solid, 2,3,4,5-letvabro?izo-;'I'-hydroxycarbazole ( 5 ) (1.27 g, 25), m.p. 216-217" (frombenzene-light petroleum) (Found: C, 28.95; HI 1 . 1 ; N,2.5; iV?-, 499. C,,H,Br,NO requires C, 28.9; H, 1-0;N, 2.8; 499); T -1.90 (lH, s, exchangeable), 1.32-1-55 (IH, In), and 2-20-2-87 (3H, ni); vmas. (KBr) 3425cm-l; ?,my. (EtOH) 222 (log E 4.58), 250 (4-72), 260 (4-67),272 (4.54), 295 (4.13), 304 (4.17), 339 (3.75), and 352(3-78) nm.A sample of compound (5) (250 mg) in dimethyl sulph-oxide (40 nil) was stirred with a suspension of potassiumhydroxide (100 mg) and methyl iodide (200 nig) a t roomtemperature during 16 11.Water (200 nil) was added;the precipitate gave 2,3,4,5-tetrabromo-N-nzetlroxycarbazole(105 mg, 41y0), m.p. 170-172" (from benzene-methanol(Found: C, 30.75; H, 1-5; N, 2.75; fV?, 513.C,,H,Br,NO requires C, 30.45; H, 1-4; N, 2.750,;; LW,513); 7 1-20-1.43 (lH, m), 2.43-2-90 (3H, ni), and 5.90(3H, S ) ; Lx. (EtOH) 224 (log E 4-48), 253 (4.59), 263 (4*58),272 (4-53), 297 (4.06), 304 (4.05), 347 (3.66), and 360(3.70) nm.By an analo-gous procedure this gave 2,3,4,5-tetrachloro-hT-hyd~~oxy-carbazole (4) (20y0), ni.p.17A175O (from benzene-light petroleum) (Found: C, 44-75; H, 1.65; N, 4.35;iW?, 321. C,,H,CI,NO requires C, 44-9; H, 1.55; N,4.35; -11, 321); -r 1.50-1.80 (lH, m) and 2.25-2.90(3H, i n ) ; vmx. (KBr) 3450 cm-l; L,,. (EtOH) 248 (log E4-54), 255 (4-48), 265 (4.33), 302 (4~01)~ 337 (3.62), and 350(3.50) nm.(c) Benzyne with nitrosobenzene. By an analogousprocedure this gave N-hydroxycarbazole (3) (1 yo), m.p.219-220" (from benzene-light petroleum) (Found: C ,79.15; H, 5-05; N, 7.75; M?, 181. C12H,N0 requiresC, 78.65; H, 4.9; N, 7.6; M , 181); -r 1*70-2-00 (2H,ni) and 2.30-3.00 (6H, in); vlnaX. (KBr) 3430 cni-l;A,,,,,. (EtOH) 233 (log E 4-65), 244 (4*41), 257 (4-33), 293(4.26), 324 (3.65), and 337 (3-61) nm.(d) Tetrabrovnobeizzyne with p-nitrosot~Zuene.~* This gave2,3,4,5-tetrabro~no-N-hydroxy-7-methylcarbazole (6) ( 29(y0),m.p.219-221" (from methanol) (Found: C, 30.7; H,1.5; N, 2.7 ; fWt, 513. C,,H,Br,NO requires C, 3045;H, 1.4; N, 2.75; M , 513); Yn/e 492.7305 ( i W - 16;C,,H,7BBr,N requires 492.7295) ; T 1-72br (IH, s), 1.5!)br(2H, q, 111 8.9 Hz), and 7.55 (3H, s); v,,,. (KBr) 3460 cm-l;l4 E. H. Bartlett, C. Eaborn, and D. R. M. Walton, J . C h ~ w .SOC. ( C ) , 1970, 1717.(b) Tetvachlorobenzyne with nitrosobenzene.innL (EtOH) 223 (log E 4-63), 250 (4*76), 203 (4*72), 270(4-60), 298 (4-21), 307 (4~23)~ 344 (3.78), and 360 (3.80) nni.This gave2,3,4,5-tetrabronzo-N-l~ydroxy-7-~nethoxycarba~oZe ( 7 ) ( 13),m.p. 237-238" (from benzene-light petroleum) (Found :C, 30.2; H, 1.2; N, 2.7 ; M?, 529.C,,H,Br,SO, requiresC, 29.5; H, 1-35; N, 2.65; M , 529); 7 1-lbr (lH, s,exchangeable) 2.00 ( l H , d, 111 2.7 Hz), 2.45 (lH, d, 1118-2 Hz), 2.80 (IH, q, I 8-2 and 2.7 Hz), and 6-17 (3H, s);vmas. (liBr) 3450 cm-l; Lx. (EtOH) 246 (log E 4-84), 256(4.21), 266 (4*20), 277 (4~17)~ 311 (3-80), and 365 (3.39) nm.(f) Tetrabrornobenzyne with o-nitrosoanisole. This gave2,3,4,6-tetvabro~no-N-Iiydroxy-9-nzetho~ycarbazole (8) (1 60/,),n1.p. 198-201" (from benzene-light pctrolcum) (Found:C, 29.55; H, 1.3; X, 2-60,;; iW7, 520); 7 1.82 (lH, q, /I 6-8and 2.7 Hz), 2.58-2.95 (BH, ni), and G-00 (3H, s) ; vnL3u. (KBr)3460 cin-1; iIi,ax. (EtOH) 230 (log E 4-70), 252 (1-78), 293(4.07), and 343 (3.81) nni.(8) Tetmbvoriz obenzyne with m-nitrosotoluene.This gavea mixture of 2,3,4,5-tetrabromo-N-hydrosy-6-mctliyl- and-8-niethyl-carbazoles (9) (Oyo), T 6-95 and 7-50 (Me) in theratio 2 : 1.Prepamtion of 1,2,3,4- Tetrnch loro- 6-nzeth ylnapht hale izefrom ~-BYoMzo-~,~,~, 8-tetrachloro-3,4-cli~iy~~o-9-utiet~iyl- 1,4-etheno~zaplitliale.lz-2( 1H)-one (lO).-The ketone (10) 11 (400nig) and hydroxylamine hydrochloride (200 nig) weredissolved in pyridine (25 nil), lieatecl a t 80" for 2 11, andpoured into ice-water (200 ml). The precipitate gave theoxirize (12) (330 mg, 79y0), m.p. 202-203" (from benzene-methanol) (Found: C, 37.65; H, 2.0; N, 3.3; M i , 415.C,,H,BrCl,XO required C, 37.55; H, 1.5; N, 3.35;The oxinie (12) (300 nig) was heated in diinethylformaniide(20 nil) and triethylamiiie (1 ml) at ca. 100" for 3 11. Thesolution was evaporated in vacuo and the residue waspurified by preparative layer chromatography, giving alower band of unchanged oxime (99 nig) and an upper bandof 1,2,3,4-tetrachloro-6-methylnaplitlialene (14) (65 mg,38y0), 1ii.p. and mixed m.p. 125-127" (from ethanol),identical (u.v., i.r., and lH n.ni.r. spectra) with an authenticsample.llPreparation of 1,2,3,4-Tetraclilovo-5-~izetlro~y~~aplrfl1alenefrom 3-Bromo-5,6,7,8-tetrac~1loro-3,4-d~~iydro-4-~~~et~io~y-1,4-ethenonaphthaZen-2( IH)-one (1 1) .-By an analogous pro-cedure the ketone ( 1 1) was converted into the oxime (13)and thence into 1,2,3,4-tetrachloro-5-metlioxy1iapht1ialeiie(15) (47y0), n1.p. and mixed 1n.p. 134-136" (fromethanol), identical (u.v., i.r., and lH n.1ii.r. spectra) witli anauthentic sample.ll(e) Tetrabronzobenzyne with p-nitrosoanisole. l5A!!, 416).We thank the S.R.C. for research studentships (toP. C. B. and J. M. S.) and for help in obtaining accuratemass measurements (through the P.C.M.U., Harwell).4/1364 Received, 8th July, 19741l5 J. T. Hayes, E. H. De Butts, and H. L. Young, J . Org.Chem., 1966, 32, 153