Synthetic studies on indoles and related compounds. XXV. The Friedel-Crafts acylation of ethyl 1H-indole-2-carboxylate. (2).

Tani, Masanobu; Aoki, Tsuyoshi; Ito, Sadao; Matsumoto, Shokei; Hideshima, Mami; Fukushima, K.; Nozawa, R.; Maeda, T.; Tashiro, M.; Yokoyama, Yuusaku; Murakami, Yasuoki

doi:10.1248/cpb.38.3261

Cited by 23 publications

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“…In most cases, a mixture of regioisomers was obtained [10]. In our hands the F-C acylation of indolyl-2-carboxylic acid esters with maleic anhydride/AlCl 3 proceeds regioselectively on aromatic ring.…”

Section: Synthesis Of Oxobutenoic Acids 1-4mentioning

confidence: 74%

Indolyl substituted 4-oxobut-2-enoic acids. Synthesis and aza-Michael additions

et al. 2007

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Abstract:The synthesis of three new substituted 4-hetereoaryl-4-oxobut-2-enoic acids with indole ring substitutedin positions 3-, 5-and 7-is described. The addition of these Michael acceptors to 4-(1-phenylsulphonylpyrrol-3-yl)-4-oxobut-2-enoic acid in conjugate addition was explored using both racemic and chiral amines. In tandem with the crystallization-induced asymmetric transformation (CIAT) protocol the effective methodology for the synthesis of enantiomerically highly enriched substituted 2-amino-4-heteroaryl-4-oxobutanoic acids as multifunctional homotryptophan analogues was developed.

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Section: Synthesis Of Oxobutenoic Acids 1-4mentioning

confidence: 74%

Indolyl substituted 4-oxobut-2-enoic acids. Synthesis and aza-Michael additions

et al. 2007

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“…Friedel-Crafts reaction of 2, 3-unsubstituted-1-acylindoles with chloroacetyl chlorides gives the corresponding 1,6-diacylindoles [4] in excellent yields. The acylation of indoles bearing electronwithdrawing substituents (ethoxycarbonyl at C2 [5,6], or iminium at C3 [7]), under certain conditions, leads to substitution of the benzene part of the heterocycle especially at C5. However, when carrying out acylation of 2-ethoxycarbonylindole or 3-methylindole with dichloromethyl methyl ether the products were 3-formyl-or Nformyl-derivatives, respectively, in good yields [6].…”

Section: Introductionmentioning

confidence: 99%

“…The acylation of indoles bearing electronwithdrawing substituents (ethoxycarbonyl at C2 [5,6], or iminium at C3 [7]), under certain conditions, leads to substitution of the benzene part of the heterocycle especially at C5. However, when carrying out acylation of 2-ethoxycarbonylindole or 3-methylindole with dichloromethyl methyl ether the products were 3-formyl-or Nformyl-derivatives, respectively, in good yields [6]. The Vilsmeier-Haack formylation of indole on the benzenoid ring has seldom preparative value because of the lack of regioselectivity.…”

Section: Introductionmentioning

confidence: 99%

“…In this paper we reveal our results on the facile preparation of ethyl 4-, 6-and 7-formyl-1H-indole-2-carboxylates (10, 11, 12) from ethyl 4-, 6-chloromethyl-1H-indole-2-carboxylates (4, 5) [14a] The hydrolysis of (chloromethyl)indoles (4, 5, 6) took place under different conditions depending on the position of the chloromethyl group. While the 4-and 6-(chloromethyl)indoles (4, 5) required one hour in water-dioxane at 50° to complete hydrolysis, 7-(chloromethyl)indoles (6) reacted with water at 0° instantaneously, just as 5-(chloromethyl)indoles did [13]. The (hydroxymethyl)-indoles (7,8,9) can be isolated in 61-84% yields simply by evaporation of the solvents.…”

Section: Introductionmentioning

confidence: 99%

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A facile synthesis of 4-, 6- and 7-formyl-1H-indole-2-carboxylates: The CH₂SO₃H functionality as a masked formyl group

Pete

Szöllősy

Szokol

2006

Journal of Heterocyclic Chemistry

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The valuable new synthetic intermediates, ethyl 4-, 6-and 7-formyl-1H-indole-2-carboxylates (10, 11, 12) were prepared from 2-ethoxycarbonyl-1H-indole-4-, 6-and 7-methanesulfonic acids (1, 2, 3), respectively. The transformation of sulfomethyl group to formyl function was accomplished through elimination of SO 2 to yield ethyl 4-, 6-and 7-chloromethyl-1H-indole-2-carboxylates (4, 5, 6), hydrolysed to ethyl 4-, 6-and 7-hydroxymethyl-1H-indole-2-carboxylates (7, 8, 9), then oxidized to aldehydes (10, 11, 12). Protection at N1 of indole was not necessary. A marked increase in the rate of hydrolysis of 7-chloromethyl-indoles compared to that of 4-and 6-(chloromethyl)indoles was observed.

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“…Alkylation and acylation of indoles at their 3-position are the most important reactions of indole chemistry, and numerous methods have been reported. [7][8][9][10][11][12][13][14] Especially, the acylation of indoles at the 3-position has been the subject of considerable interest for a long time because their derivatives are key compounds in natural products syntheses and they have important biological activities. [15][16][17][18] However, among these, acylation using nitriles as reagents has been rarely reported.…”

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confidence: 99%

A New Methodology for Functionalization at the 3-Position of Indoles by a Combination of Boron Lewis Acid with Nitriles

Mizoi

Mashima

Kawashima

et al. 2015

CHEMICAL & PHARMACEUTICAL BULLETIN

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We discovered that a reagent comprising a combination of PhBCl 2 and nitriles was useful for syntheses of both 3-acylindoles and 1-(1H-indol-3-yl)alkylamine from indoles. The reaction proceeded selectively at the 3-position of indoles providing 3-acylindoles in moderate to high yields on treatment with the above reagent. Furthermore, the reaction provided the corresponding amine products in moderate to high yields after the intermediate imine was reduced by NaBH 3 CN. These reactions proceeded under mild conditions and are applicable to the formation of indoles functionalized at the 3-position.Key words boron Lewis acid; nitrile; indole; 3-acylindole; 1-(1H-indol-3-yl)alkylamine Sugasawa et al. reported that aniline underwent FriedelCrafts type acylation with nitrile in the presence of BCl 3 .

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Synthetic studies on indoles and related compounds. XXV. The Friedel-Crafts acylation of ethyl 1H-indole-2-carboxylate. (2).

Cited by 23 publications

References 0 publications

Indolyl substituted 4-oxobut-2-enoic acids. Synthesis and aza-Michael additions

Indolyl substituted 4-oxobut-2-enoic acids. Synthesis and aza-Michael additions

A facile synthesis of 4-, 6- and 7-formyl-1H-indole-2-carboxylates: The CH₂SO₃H functionality as a masked formyl group

A New Methodology for Functionalization at the 3-Position of Indoles by a Combination of Boron Lewis Acid with Nitriles

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Synthetic studies on indoles and related compounds. XXV. The Friedel-Crafts acylation of ethyl 1H-indole-2-carboxylate. (2).

Cited by 23 publications

References 0 publications

Indolyl substituted 4-oxobut-2-enoic acids. Synthesis and aza-Michael additions

Indolyl substituted 4-oxobut-2-enoic acids. Synthesis and aza-Michael additions

A facile synthesis of 4-, 6- and 7-formyl-1H-indole-2-carboxylates: The CH2SO3H functionality as a masked formyl group

A New Methodology for Functionalization at the 3-Position of Indoles by a Combination of Boron Lewis Acid with Nitriles

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A facile synthesis of 4-, 6- and 7-formyl-1H-indole-2-carboxylates: The CH₂SO₃H functionality as a masked formyl group