4-Chlorobenzoyl chloride → HCID 18424281, compound

HRID 1973678Notes

Reaction equation

HRID 1973678 reaction equation
[H][H].[Al+3].[Cl-].[Cl-].[Cl-].[Cl:7][C:8]1[CH:16]=[CH:15][C:11]([C:12](Cl)=[O:13])=[CH:10][CH:9]=1.[CH3:17][N:18]1[CH:22]=[CH:21][CH:20]=[C:19]1[CH2:23][C:24]#[N:25]>>[Cl:7][C:8]1[CH:16]=[CH:15][C:11]([C:12]([C:22]2[N:18]([CH3:17])[C:19]([CH2:23][C:24]#[N:25])=[CH:20][CH:21]=2)=[O:13])=[CH:10][CH:9]=1

Participants

5

Reactant 4

HCID 85014-Chlorobenzoyl chlorideHCID 905011H-Pyrrole-2-acetonitrile, 1-methyl-HCID 6451240Aluminum(III) ChlorideHCID 178418361HCID 178418361, compound

Product 1

HCID 18424281HCID 18424281, compoundYield 21%

Procedure

The uncatalyzed aroylation process of this invention surprisingly affords better yields of the product, 4-R1 -1-loweralkyl-5-aroylpyrrole-2-acetic acid ester or nitrile. Moreover, when R1 is hydrogen, the usual alpha to beta ratio of product in acylation reactions, that is, the distribution of α-aroylated and β-aroylated isomers, is very greatly shifted in favor of the α-substituted product. For example, in the AlCl3 catalyzed Friedel Crafts reaction of p-chlorobenzoyl chloride with 1-methylpyrrole-2-acetonitrile, a 21% yield of the α-product, 5-(p-chlorobenzoyl)-1-methylpyrrole-2-acetonitrile, is obtained and the ratio of this α-isomer to the corresponding β-isomer, 4-(p-chlorobenzoyl)-1-methylpyrrole-2-acetonitrile, is about 2.5:1; and in the similarly catalyzed reaction of p-toluoyl chloride with 1-methylpyrrole-2-acetonitrile, a 25% yield of the α-product, 5-(p-toluoyl)-1-methylpyrrole-2-acetonitrile, is obtained with an alpha to beta isomer ratio of 3.7:1 [see Carson et al., J. Med. Chem., 14, 646 (1971)]. In contrast, the uncatalyzed reaction of p-chlorobenzoyl chloride with 1-methylpyrrole-2-acetonitrile in refluxing xylene for about 24 hours affords 46% of the corresponding α-product with an α/β ratio of about 440:1; and the uncatalyzed reaction of p-toluoyl chloride with 1-methylpyrrole-2-acetonitrile in refluxing o-dichlorobenzene for about 4 hours affords 55% of the corresponding α-product with an α/β ratio of about 180:1.

Workup

  1. customThe uncatalyzed aroylation process of this invention surprisingly affords better
  2. customyields of the product

Sources & evidence

ORD record
ord-56a8d09a7504432c9c0d68b4eac20ca7
Source dataset
uspto-grants-1976_12
Patent number
US03998844

Reaction notes

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