The Preparation of 3-Bromoindole

Piers, K.; Meimaroglou, C.; Jardine, R. V.; Brown, R. K.

doi:10.1139/v63-353

Cited by 50 publications

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“…The success in removing neutral nitrogen compounds was explained in terms of hydrogen bonding between the chloride ion and the neutral nitrogen-containing compounds, such as carbazole, which acted as proton donors . However, it should be noted that pyridinium halide perhalide in pyridine was reported to be a good halogenation agent for indole, , and the removal by the pyridinium chloride-containing resin might also have involved halogenation.…”

Section: Adsorptionmentioning

confidence: 99%

Nitrogen Removal from Oil: A Review

2016

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The selective removal of nitrogen-containing compounds from oil and oil fractions is of interest because of the potential deleterious impact of such compounds on products and processes. Problems caused by nitrogen-containing compounds include gum formation, acid catalyst inhibition and deactivation, acid−base pair-related corrosion, and metal complexation. A brief overview of the classes of nitrogen compounds found in oil is provided. The review of processes to remove nitrogen from oil emphasizes studies that investigated denitrogenation of industrial feedstocks, such as refinery fractions, heavy oils, and bitumens. The main topics covered are hydrotreating, liquid−liquid phase partitioning, solvent deasphalting, adsorption, chemical conversion followed by separation, and microbial conversion. Chemical conversion processes include oxidative denitrogenation, N-alkylation, complexation with metal salts, and conversion in high-temperature water. There are many processes for denitrogenation by separation of the nitrogen-rich products from oil without removing the nitrogen group from the nitrogencontaining compounds. As a consequence, most of these processes are viable mainly for removal of nitrogen from low-nitrogencontent oils, typically with <0.1 wt % N. At present, hydrodenitrogenation appears to be the only industrially viable process for nitrogen removal from oils with high nitrogen content.

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Section: Adsorptionmentioning

confidence: 99%

Nitrogen Removal from Oil: A Review

2016

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“…Distillation gave 1acetoxyindole as an orange oil, b.p. 75-77 "C a t 0.015 Torr (6.8-12.6 g), m/e 176 (lo%), 175 (50), 147 ( l l ) , 146 (lo), 145 (12), 144 (13), 135 (lo), 134 (32), 133 (84), 132 (48), 131 (84), 130 (86), 129 (22), 128 (24), 127 (26), 119 (lo), 118 (94), 117 (loo), 116 (86), 115 (18), 114 (12), 105 (36), 104 (68), 103 (as), 102 (30), 101 ( l o ) , 93 (16), 92 (lo), 91 (60), 90 (72), 89 (66), 88 (28), 87 (27), 86 (20), 85 (lo), 78 (60), 77 (72), 76 (36), 75 (29), 74 (26), 66 (lo), 65 (42), 64 (60), 63 (77), 62 (68), 61 (28), and 60 (40); vmX. 1810s, 1450m, 1368111, 1321m, 1220w, 1 170s, 1 120m, 1075m, 1032m, 835m(br), and 740s, best results being obtained when the distillation was carried out in minimum light, and when the aldehyde had been prepared by ozonolysis.…”

Section: -1 49 "C 5-methoxy-2-nitrophenyla~etaldehyde [5-meo-(2)mentioning

confidence: 99%

The synthesis, reactions, and spectra of 1-acetoxy-, 1-hydroxy-, and 1-methoxy-indoles

Acheson¹,

Hunt²,

Littlewood³

et al. 1978

J. Chem. Soc., Perkin Trans. 1

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Reduction of 2-nitrophenylacetaldehyde gave the unstable 1hydroxyindole, trapped as 1 -acetoxyindole. Concurrent alkaline hydrolysis with methyl iodide present yielded 1 -methoxyindole which was substituted by electrophiles a t position 3. The 3-carbaldehyde, from a Vilsmeier reaction, was converted into 1 -methoxy-NN-dimethyltryptamine. 1.5-Dirnethoxyindole underwent the Mannich reaction forming the 3-dimethylaminomethyl derivative. 1 -Acetoxyindole with dimethylforrnamide and phosphoryl chloride yielded 2-chloroindole-3-carbaldehyde and 1 -hydroxyindole-3-carbaldehyde, while (1 -hydroxyindol-3-y1)glyoxylic acid with hydroxylarnine gave 3-cyano-1 -hydroxyindole or indole-3-nitrile oxide. The u.v., i.r., n.m.r.. and mass spectra of the 1 -hydroxyindole derivatives are discussed.RECENT interest in 1-hydroxyindole derivatives has been stimulated by the isolation from plants of five l-methoxyindole derivatives, 1,5-dimethoxygrarnine [5-Me0-( 8)] ,l 1 -met hox y-NN-dime t h yl t ryp t amine (28), 1 -met hoxyindole-3-acetonitrile (10) ,3 a derivative of l-methoxyindole-3-acetic acid called neoglu~obrassicin,~ and oxaline, the major alkaloid of PeniciZZium oxalicum, which is a complex 2,3-dihydro-l-metho~yindole.~ As secondary aliphatic amines can be oxidised to hydroxylamines by peroxy-acids and in mammals,' the possibility that Nhydroxylation of indoles could occur in vivo needs to be explored, and the biological properties of l-hydroxyand similar analogues of tryptophan, serotonin, etc. can hardly fail to be of interest. An investigation of the synthesis of compounds of these types has therefore been started, syntheses of l-acetoxy-and l-methoxy-indoles have been developed, and the first syntheses of 1,5dimethoxygramine, briefly reported,8 and l-methoxy-NN-dimet hox y trypt amine are described. RESULTS AND DISCUSSIONl-Hydroxyindole (3) was first obtained by Mousseron-Canet and Bocas by the hydrolysis with sulphuric acid2) (a hydrolysis which has been described as ' tres difficile ' and which we have failed to reproduce), followed by a reliable, carefully controlled reduction with zinc-ammonium chloride. Although

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“…The reaction was carried out a t room temperature in the presence of 72y0 perchloric acid (0.10 mole) over 30 min (13). (12) Pyridinium bromide perbromide was used in pyridine solution a t room temperature over 1 h (15). (i) The sodium hypobromite solution was prepared by dissolving bromine in 40 ml 6 N aqueous sodium hydroxide.…”

Section: Isolatio~z Of Brorninalion Productsmentioning

confidence: 99%

Pyrrole Chemistry: Iv. The Preparation and Some Reactions of Brominated Pyrrole Derivatives

Anderson¹,

Lee²

1965

Can. J. Chem.

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IVIethyl 2-pyrrolecarboxylate and 2-pyrrolecarboxaldehyde have been brominated under a variety of conditions and the isomer ratios determined. The products have been identilied as the 4-bromo, 5-bromo, and 4,5-dibromo derivatives and their structures proved. I t has been sho~vn that the bromine group in these products is not easily displaced by nucleophiles although this has been accomplished with the cyanide ion. The bromine has been removed easily by catalytic hydrogenation.In our survey of the reactions of relatively simple pyrrole derivatives (1) it appeared likely that broinination might prove both useful and interesting. A selection of types of brominating agents including molecular bromine, the bromonium ion, and the bromine atom is available (2). In turn it might prove possible to replace the broinine group by others such as cyanide or methoxyl as has been done in the thiophene and furan series (3, 4, 5). The most satisfactory starting materials appeared t o be methyl 2-pyrrolecarboxylate and 2-pyrrolecarboxaldehyde. The electron-withdrawing groups would provide a 4-directing effect. Thus a mixture of 4-and 5-isomers would be formed (1, 6 ) which might be made to favor one or the other position by a choice of the type of brominating agent. In addition, both ester and aldehyde can be converted to the acid group which then might be removed by decarboxylation. Finally, the deactivation of an electronwithdrawing group would be necessary to allow the isolation of monobrominated products in reasonable yields (7). From the reaction products we isolated 4-bromo, 5-bromo, and 4,5-dibromo derivatives for both the 2-ester and the 2-aldehyde. A small amount of the 3,4,5-tribromo-2-ester (8) was also found in one reaction, i\4ethyl 4,5-dibroino-2-pyrrolecarboxylate (9) has been reported previously. ' Identification of the monobroininated-2-esters (I) was accomplished by a series of reactions. First, nucleophilic displacement of the bromine group was carried out using cuprous cyanide in hot dimethyl sulfoxide. The yields of methyl 4-and 5-cyano-2-pyrrolecarboxylate (11) were not good but in each case a single product was obtained and characterized. Then methyl 2-pyrrolecarboxylate was forinylated by the Vilsmeier-Haack technique (3) producing a mixture (111), containing mostly the 4-formyl-2-ester along with some of the 5-formyl-2-ester. Pinder (10) has formylated the corresponding ethyl ester but obtained a considerably greater proportion of 5-forinylation. Each formyl-2-ester was then subjected to two operations. First, it was oxidized (IV) and esterified (V) to the known methyl 2,5-or 2,4-pyrroledicarboxylate ( l l ) , thus proving the orientation of substituents. A second portion of each forn~yl-2-ester was converted to the oxime (VI), dehydrated t o the corresponding 4-or 5-cyano-2-ester and used for mixed melting point and comparison of infrared spectrum with the products (11) obtained above. Further

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The Preparation of 3-Bromoindole

Abstract: The few reports in the literature describing attempts a t the direct halogenation of indole in the pyrrole ring, with bromine, chlorine, or iodine (1-3), indicate that a vigorous reaction does indeed occur. However, only in the case of iodination, and then only in

Cited by 50 publications

References 0 publications

Nitrogen Removal from Oil: A Review

Nitrogen Removal from Oil: A Review

The synthesis, reactions, and spectra of 1-acetoxy-, 1-hydroxy-, and 1-methoxy-indoles

Pyrrole Chemistry: Iv. The Preparation and Some Reactions of Brominated Pyrrole Derivatives

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