Molecules 2007, 12(11), 2546-2558; doi:10.3390/12112546
Article

Hantzsch Synthesis of 2,6-Dimethyl-3,5-dimethoxycarbonyl-4-(o-methoxyphenyl)-1,4-dihydropyridine; a Novel Cyclisation Leading to an Unusual Formation of 1-Amino-2-methoxycarbonyl-3,5-bis(o-methoxyphenyl)-4-oxa-cyclohexan-1-ene

1 BELUPO Pharmaceuticals, Inc. R&D, Danica 5, 48000 Koprivnica, Croatia 2 Institute Ruđer Bošković, Bijenička c. 54, 10002 Zagreb, Croatia
* Author to whom correspondence should be addressed.
Received: 9 November 2007; in revised form: 22 November 2007 / Accepted: 23 November 2007 / Published: 26 November 2007
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Abstract: Hantzsch condensation of two equivalents of methyl-3-aminocrotonate with (m-and p)-methoxybenzaldehyde afforded the expected products 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(m-methoxyphenyl)-1,4-dihydropyridine and 2,6-dimethyl-3,5-dimethoxycarbonyl-4-(p-methoxyphenyl)-1,4-dihydropyridine, whereas o-methoxy-benzaldehyde produced mainly 1-amino-2-methoxycarbonyl-3,5-bis(o-methoxy-phenyl)-4-oxa-cyclohexan-1-ene. The structure of the product, not previously reported in theliterature, was determined by 1D and 2D NMR spectra and its MS fragmentation. This isthe first example of cyclisation leading to a substituted pyran rather than 1,4-DHP undertypical Hantzsch reaction conditions. A plausible mechanism for its formation ispostulated.
Keywords: Hantzsch condensation; intramolecular Michael addition; deprotonation; substituted pyrane.

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MDPI and ACS Style

Filipan-Litvić, M.; Litvić, M.; Cepanec, I.; Vinković, V. Hantzsch Synthesis of 2,6-Dimethyl-3,5-dimethoxycarbonyl-4-(o-methoxyphenyl)-1,4-dihydropyridine; a Novel Cyclisation Leading to an Unusual Formation of 1-Amino-2-methoxycarbonyl-3,5-bis(o-methoxyphenyl)-4-oxa-cyclohexan-1-ene. Molecules 2007, 12, 2546-2558.

AMA Style

Filipan-Litvić M, Litvić M, Cepanec I, Vinković V. Hantzsch Synthesis of 2,6-Dimethyl-3,5-dimethoxycarbonyl-4-(o-methoxyphenyl)-1,4-dihydropyridine; a Novel Cyclisation Leading to an Unusual Formation of 1-Amino-2-methoxycarbonyl-3,5-bis(o-methoxyphenyl)-4-oxa-cyclohexan-1-ene. Molecules. 2007; 12(11):2546-2558.

Chicago/Turabian Style

Filipan-Litvić, Mirela; Litvić, Mladen; Cepanec, Ivica; Vinković, Vladimir. 2007. "Hantzsch Synthesis of 2,6-Dimethyl-3,5-dimethoxycarbonyl-4-(o-methoxyphenyl)-1,4-dihydropyridine; a Novel Cyclisation Leading to an Unusual Formation of 1-Amino-2-methoxycarbonyl-3,5-bis(o-methoxyphenyl)-4-oxa-cyclohexan-1-ene." Molecules 12, no. 11: 2546-2558.

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