Condensation Reactions of 2-Amino-N-acylphenethylamines and 2-Amino-β-acylaminostyrenes

1973 ◽  
Vol 51 (6) ◽  
pp. 881-884 ◽  
Author(s):  
F. M. F. Chen ◽  
T. P. Forrest
Keyword(s):  
Trans Isomer ◽  
Molecular Sieves ◽  
Condensation Reaction ◽  
Major Product ◽  
Fischer Indole Synthesis ◽  
Condensation Reactions ◽  
Phosphorous Oxychloride ◽  
Indole Synthesis

Molecular sieves have been used to catalyze the condensation reaction of cis-β-(o-acetotoluidino)-2-aminostyrene (4) to yield 2-methyl-3-(o-tolyl)-3H-1,3-benzodiazepine (11). A second major product from the reaction was 2-(o-toluidino)-N-acetylindole (13), an example of the type of compound presumed to be an intermediate in the Fischer indole synthesis. The formation of N-acetylindole from 13 occurred on treatment of 13 with silica or alumina.The trans isomer, 5, and the reduced analog, 6, were unreactive with molecular sieves but 6 could be converted to 4,5-dihydro-2-methyl-3-(o-tolyl)-3H-1,3-benzodiazepine by reaction with phosphorous oxychloride.

scholarly journals Convenient Synthesis of 6,7,12,13-Tetrahydro-5H-Cyclohepta[2,1-b:3,4-b’]diindole Derivatives Mediated by Hypervalent Iodine (III) Reagent

Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 960 ◽  
Author(s):  
Lei Peng ◽  
Xiaofei Zhang ◽  
Chunhao Yang
Keyword(s):  
Oxidative Coupling ◽  
Biological Activities ◽  
Condensation Reaction ◽  
Large Family ◽  
Membered Ring ◽  
Hypervalent Iodine ◽  
Fischer Indole Synthesis ◽  
Convenient Synthesis ◽  
First Time ◽  
Indole Synthesis

Bisindolyl alkaloids represent a large family of natural and synthetic products that display various biological activities. Among the bisindole compounds, 6,7,12,13-tetrahydro-5H-cyclohepta[2,1-b:3,4-b’]diindoles have received little attention. Only two methods have been developed for the construction of the 6,7,12,13-tetrahydro-5H-cyclohepta[2,1-b:3,4-b’]diindole scaffold thus far, including the classical Fischer indole synthesis conducted by reacting indole-fused cycloheptanone and hydrazines, and the condensation reaction to build the seven-membered ring. Here, we report for the first time a new route to synthesize 6,7,12,13-tetrahydro-5H-cyclohepta[2,1-b:3,4-b’]diindoles through intramolecular oxidative coupling of 1,3-di(1H-indol-3-yl)propanes in the presence of PIFA, DDQ and TMSCl with moderate to excellent yields.

Theoretical insights into the sites and mechanisms for base catalyzed esterification and aldol condensation reactions over Cu

2017 ◽  
Vol 197 ◽  
pp. 59-86 ◽  
Author(s):  
Matthew Neurock ◽  
Zhiyuan Tao ◽  
Ashwin Chemburkar ◽  
David D. Hibbitts ◽  
Enrique Iglesia
Keyword(s):  
Density Functional ◽  
Aldol Condensation ◽  
Condensation Reaction ◽  
Experimental Studies ◽  
Acid Sites ◽  
Major Product ◽  
Experimental Results ◽  
Esterification Reaction ◽  
Condensation Reactions ◽  
Theoretical Results

Condensation and esterification are important catalytic routes in the conversion of polyols and oxygenates derived from biomass to fuels and chemical intermediates. Previous experimental studies show that alkanal, alkanol and hydrogen mixtures equilibrate over Cu/SiO2 and form surface alkoxides and alkanals that subsequently promote condensation and esterification reactions. First-principle density functional theory (DFT) calculations were carried out herein to elucidate the elementary paths and the corresponding energetics for the interconversion of propanal + H2 to propanol and the subsequent C–C and C–O bond formation paths involved in aldol condensation and esterification of these mixtures over model Cu surfaces. Propanal and hydrogen readily equilibrate with propanol via C–H and O–H addition steps to form surface propoxide intermediates and equilibrated propanal/propanol mixtures. Surface propoxides readily form via low energy paths involving a hydrogen addition to the electrophilic carbon center of the carbonyl of propanal or via a proton transfer from an adsorbed propanol to a vicinal propanal. The resulting propoxide withdraws electron density from the surface and behaves as a base catalyzing the activation of propanal and subsequent esterification and condensation reactions. These basic propoxides can readily abstract the acidic Cα–H of propanal to produce the CH3CH(−)CH2O* enolate, thus initiating aldol condensation. The enolate can subsequently react with a second adsorbed propanal to form a C–C bond and a β-alkoxide alkanal intermediate. The β-alkoxide alkanal can subsequently undergo facile hydride transfer to form the 2-formyl-3-pentanone intermediate that decarbonylates to give the 3-pentanone product. Cu is unique in that it rapidly catalyzes the decarbonylation of the C2n intermediates to form C2n−1 3-pentanone as the major product with very small yields of C2n products. This is likely due to the absence of Brønsted acid sites, present on metal oxide catalysts, that rapidly catalyze dehydration of the hemiacetal or hemiacetalate over decarbonylation. The basic surface propoxide that forms on Cu can also attack the carbonyl of a surface propanal to form propyl propionate. Theoretical results indicate that the rates for both aldol condensation and esterification are controlled by reactions between surface propoxide and propanal intermediates. In the condensation reaction, the alkoxide abstracts the weakly acidic hydrogen of the Cα–H of the adsorbed alkanal to form the surface enolate whereas in the esterification reaction the alkoxide nucleophilically attacks the carbonyl group of a vicinal bound alkanal. As both condensation and esterification involve reactions between the same two species in the rate-limiting step, they result in the same rate expression which is consistent with experimental results. The theoretical results indicate that the barriers between condensation and esterification are within 3 kJ mol−1 of one another with esterification being slightly more favored. Experimental results also report small differences in the activation barriers but suggest that condensation is slightly preferred.

Modular Counter-Fischer–Indole Synthesis through Radical-Enolate Coupling

2021 ◽  
Vol 23 (3) ◽  
pp. 1096-1102
Author(s):  
Hyunho Chung ◽  
Jeongyun Kim ◽  
Gisela A. González-Montiel ◽  
Paul Ha-Yeon Cheong ◽  
Hong Geun Lee
Keyword(s):  
Fischer Indole Synthesis ◽  
Indole Synthesis

Investigation of the effect of ring size on the product distribution for the Schiff base reaction of 2-acetylcycloalkanones with diamino alkanes

1995 ◽  
Vol 73 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Raul G. Enriquez ◽  
Juan M. Fernandez-G ◽  
Ismael Leon ◽  
William F. Reynolds ◽  
Ji.-Ping Yang ◽  
...  
Keyword(s):  
Schiff Base ◽  
Condensation Reaction ◽  
2D Nmr ◽  
Product Distribution ◽  
Major Product ◽  
Ring Size ◽  
Amino Group ◽  
Amino Groups ◽  
Similar Product ◽  
Acetyl Group

The Schiff base condensation reaction of 1,2-diaminoethane with a series of 2-acetylcycloalkanones (from cyclopentanone to cyclooctanone) has been investigated and the products characterized by two-dimensional nuclear magnetic resonance. The site of attack of the amino groups, i.e., ring ketone or acetyl ketone, is determined primarily by ring size. 2-Acetylcyclohexanone yields two products in ca. 9:1 ratio, the major product where the two amino groups attack at the ring ketones of two different cyclohexanone molecules, and the minor product where one amino group attacks one ring carbonyl of one cyclohexanone while the second amino group attacks the acetyl group of another. 2-Acetylcyclopentanone yields all three possible products with the major product involving attack at the acetyl groups of two different cyclopentanones. The corresponding reactions for 2-acetylcycloheptanone and 2-acetylcyclooctanone each give a single product corresponding to attack at the acetyl groups of two different cycloalkanones. Similar product distributions are observed for the reactions of the different 2-acetylcycloalkanones with 1,4-diaminobutane. Keywords: Schiff base reactions, diketones, 2D NMR.

A continuous flow microwave-assisted fischer indole synthesis of 7-Ethyltryptophol

2017 ◽  
Vol 121 ◽  
pp. 144-148 ◽  
Author(s):  
Jianguo Xu ◽  
Jiangang Yu ◽  
Yi Jin ◽  
Jie Li ◽  
Zhiqun Yu ◽  
...  
Keyword(s):  
Continuous Flow ◽  
Microwave Assisted ◽  
Fischer Indole Synthesis ◽  
Indole Synthesis

scholarly journals Polyphosphate Ester as a Synthetic Agent. V. The Fischer Indole Synthesis with Polyphosphate Ester

1966 ◽  
Vol 14 (9) ◽  
pp. 934-939 ◽  
Author(s):  
Yuichi Kanaoka ◽  
Yoshio Ban ◽  
Koichi Miyashita ◽  
Kimiko Irie ◽  
Osamu Yonemitsu
Keyword(s):  
Fischer Indole Synthesis ◽  
Indole Synthesis

One-Pot Reactions Involving the Fischer Indole Synthesis and Friedel–Crafts Reactions

2018 ◽  
Vol 61 (7-8) ◽  
pp. 685-688 ◽  
Author(s):  
Hien Vuong ◽  
Samantha Duarte ◽  
Douglas A. Klumpp
Keyword(s):  
One Pot ◽  
Fischer Indole Synthesis ◽  
Indole Synthesis
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