Issue 19, 2016

Peculiarities of 2-amino-3-R-4-aryl-4H-pyranes multicomponent synthesis derived from 1H-2,1-benzothiazin-4(3H)-one 2,2-dioxide

Abstract

The new 2-amino-3-R-4-aryl-6-ethyl-4,6-dihydropyrano[3,2-c][2,1]benzothiazine 5,5-dioxides were synthesized via three-component interaction of 1H-2,1-benzothiazin-4(3H)-one 2,2-dioxide with arylcarbaldehydes and active methylene nitriles. Depending on the nature of an active methylene nitrile and an arylcarbaldehyde this interaction can lead either to the target 2-amino-4H-pyrans or to the stable triethylammonium salts of bis(1H-2,1-benzothiazin-4(3H)-one 2,2-dioxides) (bis-adducts). The latter is a completely new product of such interaction. The structure of the bis-adduct was confirmed by single crystal X-ray diffraction. Actually, the formation of stable triethylammonium salts (as the process competitive with the 2-amino-4H-pyrans formation) appeared to be reversible and their interaction with active methylene nitriles led to the formation of 2-amino-4H-pyrans. The extended and adjusted mechanism of the three-component interaction, that includes the bis-adducts formation stage, was proposed. Taking into account the peculiarities of the mechanism, we were capable to control the reaction selectivity.

Graphical abstract: Peculiarities of 2-amino-3-R-4-aryl-4H-pyranes multicomponent synthesis derived from 1H-2,1-benzothiazin-4(3H)-one 2,2-dioxide

Supplementary files

Article information

Article type
Paper
Submitted
19 Nov 2015
Accepted
22 Jan 2016
First published
29 Jan 2016

RSC Adv., 2016,6, 16087-16099

Author version available

Peculiarities of 2-amino-3-R-4-aryl-4H-pyranes multicomponent synthesis derived from 1H-2,1-benzothiazin-4(3H)-one 2,2-dioxide

D. A. Lega, N. Yu. Gorobets, V. P. Chernykh, S. V. Shishkina and L. A. Shemchuk, RSC Adv., 2016, 6, 16087 DOI: 10.1039/C5RA24566D

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