Molecules 2013, 18(2), 1869-1880; doi:10.3390/molecules18021869
Article

Silica-Supported Polyphosphoric Acid in the Synthesis of 4-Substituted Tetrahydroisoquinoline Derivatives

Department of Organic Chemistry, University of Plovdiv, 24 Tzar Assen str., 4000 Plovdiv, Bulgaria
* Author to whom correspondence should be addressed.
Received: 19 December 2012; in revised form: 21 January 2013 / Accepted: 22 January 2013 / Published: 1 February 2013
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Abstract: We report herein an application of an α-amidoalkylation reaction, as an alternative efficient synthesis of 4-aryl- and 4-methyl-1,2,3,4-tetrahydroisoquinoline derivatives. The amides required for this purpose would result from reaction of aminoacetaldehyde dimethylacetal with different substituted benzenes in polyphosphoric acid, followed by acylation of the obtained amines with different acid chlorides or sulfochlorides. We compared the cyclisation step using conventional (milieu of acetic-trifluoracetic acid = 4:1) and solid supported reagents (SiO2/PPA), as recovered, regenerated and reused without loss of its activity catalyst. We found that in comparison to conventional methods, the yields of the reaction are greater and the reaction time is shorter.
Keywords: 4-substituted tetrahydroisoquinoline; cherylline analogues; α-amidoalkylation reaction; silica-supported polyphosphoric acid (SiO2-PPA)

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MDPI and ACS Style

Manolov, S.; Nikolova, S.; Ivanov, I. Silica-Supported Polyphosphoric Acid in the Synthesis of 4-Substituted Tetrahydroisoquinoline Derivatives. Molecules 2013, 18, 1869-1880.

AMA Style

Manolov S, Nikolova S, Ivanov I. Silica-Supported Polyphosphoric Acid in the Synthesis of 4-Substituted Tetrahydroisoquinoline Derivatives. Molecules. 2013; 18(2):1869-1880.

Chicago/Turabian Style

Manolov, Stanimir; Nikolova, Stoyanka; Ivanov, Iliyan. 2013. "Silica-Supported Polyphosphoric Acid in the Synthesis of 4-Substituted Tetrahydroisoquinoline Derivatives." Molecules 18, no. 2: 1869-1880.

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