A convenient synthesis of (z)-3-(α-alkoxycarbonyl-α-cyanomethylene)-2-oxo-1,2,3,4-tetrahydroquinoxalines and related compounds
✍ Scribed by Yoichi Yamada; Heinosuke Yasuda
- Publisher
- Journal of Heterocyclic Chemistry
- Year
- 1998
- Tongue
- English
- Weight
- 485 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0022-152X
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✦ Synopsis
Abstract
(Z)‐3‐(α‐Alkoxycarbonyl‐α‐cyanomethylene)‐2‐oxo‐1,2,3,4‐tetrahydroquinoxalines 3 and (Z)‐3‐(α‐alkoxycarbonyl‐α‐cyanomethylene)‐3,4‐dihydrobenzo[g]quinoxalin‐2(1__H__)‐ones 5 possessing various alkoxycarbonyl groups were prepared in good yields directly from the reaction of dialkyl (E)‐2,3‐dicyanobutendioates 1 with o‐phenylenediamine (2) or with 2,3‐diaminonaphthalene (4), respectively. Furthermore, 2,3‐diaminopyridine (6) and 3,4‐diaminopyridine (7) were reacted with the diethyl ester 1b to give (Z)‐2‐(α‐cyano‐α‐ethoxycarbonylmethylene)‐1,2‐dihydro‐4__H__‐pyrido[2,3‐b]pyrazin‐3‐one (8) and (Z)‐3‐(α‐cyano‐α‐ethoxycarbonylmethylene)‐3,4‐dihydro‐1__H__‐pyrido[3,4‐b]pyrazin‐2‐one (9), respectively. The structural studies of 3, 5, 8, and 9 were carried out by nmr experiments in some details.
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## Abstract Chemoselective synthesis of 4‐oxo‐2‐aryl‐4,10‐dihydropyrimido[1,2‐__a__][1,3]benzimidazol‐3‐yl cyanides from three‐component reactions of 2‐aminobenzimidazole, aldehydes, and ethyl cyanoacetate __via__ [3+3] atom combination is reported. The effect of different base catalysts such as so