Maatman, Hendrik

Oltay, Ernst

Penninger, Johannes M.L.

University of Twente Research Information

cipitate is filtered off and the filtrate is evaporated to remove solvent ; the oily residue is distilled at 14O0C/O.4 torr [yield of (6) : 0.20g (64%); colorless stable oil]. Received: July 6, 1972 [Z 683b IE] German version: Angew. Chem. 84, 993 (1972) 111 Immonium Chemistry, Part 5.-Part 4: H. G .  Viehe, Th. van Vyue, and Z .  Janousek, Angew. Chem. 84,991 (1972). Angew. Chem. internat. Edit. 11,916 (1972). [2] J .  H. Ottenheym and J .  W. Garritsen, British Pat. 901 169, (1962); Chem. Abstr. 58, 6810, (1963); H. Ulrich: The Chemistry of Imidoyl Halides. Plenum Press, New York 1968 p. 207. [ 3 ]  H .  G.  Viehe, Lecture at the Nottingham Symposium on Acetylenes, July 1971 ; E .  Golfin and I: Legrand, Dissertations, Universite de Louvain, in preparation. Synthesis of the First Oxide of Tetrasulfur Tetranitride By Herbert W. Roesky and Olaf Petersen''] We reported recently the synthesis of S,N,O,Cl, the S,S,S'-trioxide of a six-membered sulfur-nitrogen ring"]. We have now succeeded in isolating the first oxide of the S,N, ring. N,N'-Bis(trimethylsily1)sulfur diimide reacts with the anhydride of fluorosulfuric acid with cleavage of trimethyl- fluorosilane and trimethylsilyl fluorosulfate to give S,N,O, (2). 2 (CH3)3Si-N=S=N-Si(CH& + 2 FSOz-O-SOzF - ( 1 )  o\ A 4% 40 + 2 (CH3)&F + 2 (CH3)3SiOSOzF A O4 'N* 4N 0 S (2) is a yellow solid which sublimes at 8&90°C under oil-pump vacuum. Decomposition point : 11 5 to 120°C. The compound is not formed on reaction of ( I )  with S0,C12. In the presence of moisture it decomposes with loss of SO, and turns brown in color. The given structure follows from complete elemental analysis and the MS and IR data. The mass spectrum contains the molecular ion at rnje = 248 with a relative intensity of only 0.1%. This is accompanied by the following characteristic ions: m/e = 216, S,N,02 124, S3N, (4%); 110, S,N (1.5%); 92, S2N, (8%); 78, S,N (14%); 64, SO, (17%); 48, SO (16%);46, NS (100%); 32, S (16%);184,S4N4(1%);170,S,N,O2(13%);138,S3N3(1 %I; (9%); 28, N2 (17%). In the IR spectrum absorptions occur at (cm-'): 1420 (s), 1400 (s), 1328 (vs), 1280 (w), 1218 (m), 1202 (m), 1175 (s), 1137 (vs), 1115 (vs), 1072 (w), 1018 (w), 980 (w), 895 (w), 850 (w), 830 (w), 715 (s), and 704 (s). The bands at 1420 and 1400 cm-' are assigned to asymmetric S=O stretching vibrations. [*I Prof. Dr. H W. Roesky and Dipl.-Chem. 0 Petersen Anorganisch-chemisches Institut I der Universitat 6 Frankfurt, Robert-Mayer-Strasse 7-9 (Germany) Experimental. To a solution of ( I )  (0.1 mol) in CCl, (200 ml) in a 500-ml two-necked flask fitted with dropping funnel is added drop- wiseover3hasolutionofFzS,0, (0.1 mol)inCC14(100ml). The mixture is then boiled under reflux for 4h and the sol- vent and volatile products subsequently removed by eva- poration and condensation into a trap under vacuum. The residue remaining in the flask is sublimed under oil-pump vacuum. Four sublimations are required for complete purification of the product. Yield 2.5 g (5%). Received: July 18,1972 [Z 685 IE] German version: Angew. Chem. 84.946 (1972) [l] H. W. Roesky, Angew. Chem. 83, 253 (1971); Angew. Chem. internat. Edit. 10, 266 (1971). 121 U.  Wannagat and H .  Kuckertz, Angew. Chem. 74, 117 (1962); Angew. Chem. internat. Edit. /, 113 (1962). Side-Chain Alkylation of Toluene with Ethylener'] By Ernst Oltay, Johannes M .  L. Penninger, and Hendrik Maatman"' In the presence of metallic Na or K as a catalyst, with or without promoter, the three hydrogen atoms of the methyl group in toluene can be stepwise alkylated with ethylene, the most highly alkylated product formed being 3-ethyl- 3-phenylpentane12-41. In the presence of butyl-Li and a di-tertiary amine, toluene reacts with ethylene to give a straight-chain homologous series". 'I. We have found that toluene reacts with ethylene in the absence of a catalyst even at as low a temperature as z 400°C and a pressure of 50 atm to give alkylbenzenes having straight alkyl chains (for instance, n-propylbenzene and n-pentylbenzene). The reaction proceeds via free radicals. Compounds yielding benzyl radicals catalyze the reaction. Thus the conversion of toluene and the selectivity of the side-chain alkylation to give straight-chain alkylbenzenes are favored by addition of benzyl chloride and benzyl bromide (Table 1). All compounds were isolated by preparative gas chroma- tography and identified by NMR, IR, and MS, as well as by their gas-chromatographic retention times. The new reaction is of general applicability. ['I Prof. Dr. E. Oltay, Dr. ir. J. M. L. Penninger, and H. Maatman Technische Hochschule Twente, Laboratory for Industrial Chemistry Enschede, Postbus 217 (Netherlands) 918 Angew. Chem. internat. Edit. 1 VoL I 1  (1972) 1 No. I0 Table 1 .  Side-chain alkylation of toluene with ethylene. Cr-Ni-Mo steel autoclave (314 cm'), 20 g (217 mmol) toluene, 7 g (250 mmol) ethylene. 380 C. 55 atm, 2 h. C ,  H,CH,Br Toluene Yield [mol-";,I all straight [ w1:y J conversion n-propyi- ,~-pentyl- chain alkyl- C%1 benzene benzene benzenes ~ 10.6 32.7 12.4 45 1 0.1 13.3 42 1 25.1 67.2 0.5 [7] 19.3 56.7 25 5 82.2 1 .o 24.0 60.9 14.5 75.4 Received: July 17, 1972 [Z 686 IE] German version: Angew. Chem. 84,  947(1972) [ I ]  Side-Chain Alkylation of Alkylbenzenes with Olefins, Part I .  [2] H .  Pines, J A.  Veselj. and V.  N .  Ipariefl. J.  Amer. Chem. SOC. 77,554 (1955); H .  P i n a a n d  V.  N .  !parief, US-Pat. 2721887 (1955). [3] Sr. E. Volrz. J. Org. Chem. 22.48 (1957). [4] J .  P. Napolirano and R. D. Clossen. US-Pat. 3449455 (1969). [5] G. G .  Eherhardr, Belg. Pat. 633482 (1963). [ 6 ]  G. G. Eherhardt and W .  A. Bur&, J. Org. Chem. 29,2928 (1964). 171 We obtained almost identical results with an  equivalent amount of benzyl chloride. The Mechanism of the Bischler-Napieralski Reaction"] By Gabor Fodor, J .  Gal, and B. A .  Phillips['] The fragmentation of cyclic benzamides of type (1) upon the action of phosphorus pentabromideI2' leads to a,  o- dibromoalkanes and benzonitrile. Our recent studies have revealed that the first step of this reaction is in fact the formation of the a-bromoiminium tribromide (2a)  which can be in more than 90% yield. Reduction of this compound with an olefin (e .g .  cyclohexene) results in the quantitative formation of the monobromide (2b)I"I. Mild heating of (26) gave the N-(a-bromoalky1)imidoyl bromide (with n = 5 )  which was also synthesized via its hydrobromide from N-(5-bromoamyl)benzamide and car- bony1 bromideI4] (or phosphorus pentabromide) followed by reduction of Br,- to Br-, and mild heating. Imidoyl bromides-unlike imidoyl chIoride~[~~-have not been previously known in pure form. We have found that imidoyl bromides equilibrate with nitrilium bromides ( 4 )  and hence are the intermediates which occur after the bromoiminium bromide in the degradation of the amide ( I )  [61. [*] Prof. Dr. G Fodor. Dr. J.  Gal. and B A Phillips Department of Chemistry, West Virginia University Morgantown, West Virginia 26506 (USA) However, if unlike in the amide degradation there is an internal nucleophile present, it should react with the carbon of the nitrilium group. This is the case in the Bischler-Napieralski ring closure reaction of N -  acyl-2- arylethylamines (5) under the influence of P,O,, POCI, or  ZnC1, to give the 3,4-dihydroisoquinolines (8 ) .  To prove this we have converted N-[2-(3,4-dimethoxyphenyl)- ethyllbenzamide (5a) at room temperature with phospho- rus pentachloride in CCI, into the crystalline hydrochloride of the benzimidoyl chloride (6a)  (80% yield). This salt loses hydrogen chloride slowly at room temperature (more rapidly at SSOC) and gives quantitatively the cyclized prod- uct, i. e. 6,7-dimethoxy-l-phenyl-3,4-dihydroisoquinoline hydrochloride (8a). c=o I (5) C6H5 - 'V;@ R c The reaction can be followed with NMR using CDCI, as solvent: (6a)  shows a singlet a t  3.82 ppm for the six meth- oxy protons which is converted to two singlets at 3.80 and 4.09 ppm as the cyclization to (8u) proceeds. The aromatic region is also informative in that the original peak at 6.82 ppm integrating for three protons changes to two singlets a t  6.94 and 7.13 ppm which integrate for one proton each. Addition of a Lewis acid (ZnCI,, SnCl,, etc.) enhanced the rate of cyclization. This could be explained through a push-pull displacement of chlorine from the imide carbon in ( 6 )  by the nucleophilic arene carbon, synchronously with attack of the Lewis acid upon the chloride ion. Alternatively, one can suppose intermediary formation of the nitrilium ion (7a) ,  which could then react very f a d 7 ]  with the aromatic carbon. In order to slow down the cyclization, and detect the nitrilium ion, N-(2-phenylethyl)benzamide (5b )  was con- verted into the crystalline imidoyl chloride hydrochloride18] and then into the base (6b), which was distilled at 132"C/ 0.045 torr. If stannic chloride is added to a solution of (66)  in a NMR tube, the triplet a t  4.02 ppm of the methylene adjacent to nitrogen disappears and a new CH, triplet appears a t  4.68 ppm, indicating nitrilium ion (76)  forma- tion. Upon standing at 25 "C this triplet is slowly (faster upon heating) displaced to 4.20 ppm, which is the chemical shift of the methylene protons at  C-3 in the hydrochloride of the 3,4-dihydroisoquinoline (8b). Moreover, the N-(2- phenylethy1)benzonitrilium ion could also be trapped as the crystalline hexafluoroantimonate. I t  reacts subsequent- ly in solution to give the dihydroisoquinolinium hexa- fluoroantimonate. N-(2-Phenylethyl)benzonitrilium complexes have previous- ly been obtained from a metal halide complex of the nitrile and 2-phenylethyl chloride['], reminiscent of the Ritter reactionr"! The product was also cyclized into the Angew. Chem. internal. Edit. 1 Vol. I 1  f1972) 1 No.  10 919 

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Side-Chain Alkylation of Toluene with Ethylene

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Side-Chain Alkylation of Toluene with Ethylene

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