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The PPA induced Fischer indolization of 4-acetonyl-2,6-piperidinediones 4 takes place both at the methylene and the methyl carbons, although the latter regioisomer (3) undergoes a further cyclization of the imide moiety upon the indole 3-position followed by ring-opening of the resulting intermediate 9 to give tetrahydrocarbazolone 8. Fragmentation of the two possible regioisomers 3 and 7 to 2-methylindole occurs at higher temperatures. This process is more pronounced when using 4-acetonyl-3,4-dihydro-2(1H)-pyridone 13 as the substrate for the indolization. The use of N-acetylphenylhydrazone derivatives leads to similar results as a consequence of the deacylation of the initially formed indole derivatives. In this case, an additional C-acylation of the indole ring also occurs. 相似文献
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The heat of formation (H
f) of unsymmetrical ketone phenylhydrazones and their enehydrazine tautomers was calculated by the semi-empirical quantum-chemical AM1 method. It is concluded that from H
f values it is possible to judge the regioselectivity of indolization of unsymmetrical ketone phenylhydrazones.Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 220–221, January, 1993. 相似文献
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Phenylhydrazones containing hydroxy, alkoxy and acyloxy groups are synthesized from aromatic aldehydes of vanillin series by reaction with phenylhydrazine. 相似文献
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Thomas Zimmermann 《Journal of heterocyclic chemistry》2000,37(6):1571-1574
N‐Substituted N‐phenylhydrazines 1, α‐branched ketones 2 and perchloric acid react in boiling ethanol to give via the in situ formed hydrazones 3 1,2,3,3‐tetrasubstituted 3H‐indolium perchlorates 4. The scope and limitations of this facile synthesis of 3H‐indolium derivatives which combines the hydrazone formation and the Fischer indolization to an one‐pot procedure are discussed. 相似文献
7.
The indolization of deoxybenzoin ,, (Me, MeO, Cl), -NO2 and -EtO-phenylhydrazones (1) by the above reaction has been examined. All the reactions are carried out at room temperature and high yields of the corresponding indoles (2) are obtained even when -NO2 substituent is present. In this case longer reaction time is necessary. Alkoxyphenylhydrazones give the corresponding indoles (2) in high yields without showing collateral reactions which indeed are present in several Fischer routes on these derivatives. -Substituted phenylhydrazones (1) give a mixture of 4- and 6-substituted indoles in which the 6-isomer is always prevalent, a feature not inherent in the Fischer reactions. The regioselectivity is enhanced by the substituent steric hindrance increasing. The reaction can be also carried out at 0°C with a further improvement of its regioselectivity. 相似文献
8.
Gerhard W. Fischer 《Journal of heterocyclic chemistry》1993,30(6):1517-1519
Tetrazolyl-substituted enamino ketones 1 react with various amidines 2 to give 5-(1-phenyl-1H-tetrazol-5-yl)pyrimidines 3 . In the case of the chloroacetyl enamine 4 4-(N,N-dimethylaminomethyl)-substituted tetra-zolylpyrimidines 5 were obtained. Subsequent hydrolysis of the 4-trifluoromethyl derivatives 3b, 3d and 3g afforded the corresponding 5-(1-phenyl-1H-tetrazol-5-yl)pyrimidine-4-carboxylic acids 6 . 相似文献
9.
Raju R. Kale Virendra Prasad Divya Kushwaha Vinod K. Tiwari 《Journal of carbohydrate chemistry》2013,32(2):130-142
A facile, simple, and high-yielding synthetic protocol for novel glycosyl tetrazoles has been devised from different carbohydrate-containing amides using benzotriazole methodology under mild reaction condition. 相似文献
10.
Gerhard W. Fischer 《Journal of heterocyclic chemistry》1994,31(6):1529-1534
The acid-catalyzed reaction of 1-aryl-5-(2-dimethylaminovinyl)-1H-tetrazoles 2 with arylamines suitably functionalized in the ortho-position resulted in Z-configurated transamination products which were cyclized to novel 3-tetrazolylquinolines by the action of sodium ethoxide. Thus, on reacting 2 with 2-aminoacetophenone or 2-aminobenzophenone, respectively, the 2-[2-(1-aryl-1H-tetrazol-5-yl)vinyl-amino]aryl ketones 3a-g were obtained, the cyclization of which gave 4-substituted 3-(1-aryl-1H-tetrazol-5-yl)quinolines 4 . In the case of the transamination products 3h-1 , prepared from 2 and methyl anthranilate, the ring closure afforded 3-(1-aryl-1H-tetrazol-5-yl)-1H-quinolin-4-ones 5 . Starting from 2 and anthranilonitrile 4-amino-3-(1-aryl-1H-tetrazol-5-yl)quinolines 10 were obtained via the corresponding intermediates 9 . 相似文献
11.
Fischer indolization of ethyl pyruvate 2-methoxyphenylhydrazone (1) with p-toluene-sulfonic acid in benzene in the presence of an enolizable dicarbonyl or an indolic compound gave either an indole product having an active methine group at C6 or a novel type of 3,6′-biindole compound. Structures of the products were established by NMR spectra and chemical evidence. 相似文献
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Two naturally occurring 6-substituted indoles, 6-(3-methylbuta-1,3-dienyl)indole (2) and 6-(3-methyl-2-butenyl)indole (5), were synthesized by using an advanced Fischer indolization of a 2-methoxyphenylhydrazone derivative. 相似文献
14.
Caterina Canu Boido Vito Boido Federica Novelli Fabio Sparatore 《Journal of heterocyclic chemistry》1998,35(4):853-858
On the basis of previous occasional findings, the Fischer indole cyclization of ten ketone phenylhydrazones containing moieties of increasing bulkiness was investigated in order to isolate eventual side products. In the cases of the three 2-, 3- and 4-acetylpyridine phenylhydrazones the corresponding 2-pyridylindoles were the sole compounds so far isolated. In all the remaining cases, beside the indoles a mixture of basic compounds was obtained. In all cases aniline and a 2-substituted (2-methyl or 2-phenyl)benzimidazole were formed, the last resulting through an apparent ortho-semidinic rearrangements of phenylhydrazones. Starting from methyl isopropyl ketone phenylhydrazone a compound of formula C11H15NO was also isolated, to which the structure of 3-(4-aminophenyl)-3-methylbutanone was assigned on the basis of ir, nmr spectra and of the chemical reactivity. The formation of this compound seems related to a para-benzidine-like rearrangement of phenyl hydrazone. 相似文献
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The synthetically interesting processes available for indolization reactions are discussed and illustrated in tabular form and particular emphasis is placed on the more recent methods. 相似文献
17.
Gordon L. Bundy Theresa M. Schwartz John R. Palmer Lee S. Banitt William Watt 《Journal of heterocyclic chemistry》2000,37(6):1471-1477
The high‐yield synthesis of the 2,4‐diaminopyrrolo[2,3‐d] pyrimidine 4 (PNU‐87663) via a Bischler‐like alkylation‐cyclization sequence was reported earlier. We describe herein an alternative synthesis of this potent antioxidant and several analogs based on the thermal Fischer indolization, starting from hydrazino substituted pyrimidines 5 and 13. In several cases where the thermal Fischer indolization failed, attempts to catalyze the reaction with Lewis acids, especially ytterbium triflate, led to the surprising and unprecedented formation of pyrazolo[3,4‐d]pyrimidines, e.g. 1‐methyl‐3‐phenyl‐4,6‐di‐1‐pyrrolidinyl‐1H‐pyrazolo[3,4‐d]pyrimidine (24), with the loss of the elements of methane. Mechanistic details of this transformation remain to be investigated. 相似文献
18.
M. A. Yurovskaya A. V. Karchava Yu. G. Bundel' 《Chemistry of Heterocyclic Compounds》1992,28(9):1000-1003
A study has been made of the influence of solvents on the process of indolization of the methiodide of sym-3-nitrocollidine by the action of the N-methylimine of methyl ethyl ketone. An inversely proportional relationship has been found between the content of the 3,7-unsubstituted indole in the indole fractions and the donor strength of the solvent.For Communication 9, See [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, 1187–1190, September 1992. 相似文献
19.
以甲酰基二茂铁6为原料, 通过与NH4OH•HCl的缩合反应得到二茂铁肟7, 再经脱水剂脱水得到二茂铁腈8, 最后在(n-C4H9)3SnCl的作用下与NaN3反应生成新化合物二茂铁四唑(9). 以甲酰基二茂铁为原料, 在对甲苯磺酸(PTSA)的催化作用下与原甲酸三甲酯反应生成二甲基二茂铁缩醛(10), 然后与(R)-(-)-3-氯-1,2-丙二醇反应得到新的二茂铁缩醛衍生物12, 12再与NaN3发生取代反应得到新的二茂铁缩醛衍生物13. 而新的二茂铁缩醛衍生物15的合成则是先由(R)-(-)-3-氯-1,2-丙二醇与CH3OH在NaOH的作用下生成(R)-(-)-1-甲氧基-2,3-丙二醇(14), 再由14与二甲基二茂铁缩醛(10)反应得到的. 所合成的新化合物都用MS, 1H NMR和IR谱确证了它们的结构. 相似文献
20.
3-(Trialkylstannyl)propyl aryl sulphides (R3SnCH2CH2CH2SR′; R = Me, Et, Bu; R′ = Ph, p-tolyl) were prepared by the addition of arenethiols to allyltrialkyltin compounds. Preferential cleavage of the allyl group by the reaction R3SnCH2CHCH2+R′SH→R3SnSR′+CH3CHCH2 occurred when R = R′ = Bu and R = R′ = Ph. Diallyltin dibromide and benzenethiol gave stannous bromide. Mössbauer parameters of the products are recorded. 相似文献