Investigation of the Interaction of 5-Aryl-2,3-dihydro-2,3-furandiones with Compounds Containing C=N and C≡N Bonds Simultaneously

Abstract

method in [4 + 2] cycloaddition.It is known that thermolysis of 5-aryl-2,3-dihydro-2,3-furandiones (benzene, 80°C) is accompanied by the elimination of carbon monoxide and leads to 3-aroyl-6-aryl-4-hydroxy-2H-pyran-2-ones [1]. The formation of substituted pyrans in this reaction is explained by the dimerization of aroylketenes, the primary thermolysis products. The fact of forming aroylketenes as a result of thermal decarbonylation of furandiones was reliably confirmed in [2].It was shown previously that aroylketenes generated in a similar way react with compounds containing a C=N bond and an activated C≡N bond with the formation of [4 + 2] cycloaddition products, 6-substituted 3,4-dihydro-2H-1,3-oxazin-4-ones [3][4][5] or 4H-1,3-oxazin-4-ones [6-8] respectively. Many of the 1,3-oxazines obtained in this way display biological activity [9], which makes it expedient to study these reactions further.In the presence of compounds with an unactivated cyano group (MeCN, PhCN) aroylketenes are dimerized [7].The interaction of 5-aryl-2,3-dihydro-2,3-furandiones with compounds containing C=N and C≡N bonds simultaneously, and also activated and unactivated C≡N bonds is practically unstudied. It is known only that as a result of the reaction of 5-aryl-2,3-dihydro-2,3-furandiones with methylenaminoacetonitrile, a compound containing isolated C=N and C≡N bonds (toluene, 110°C, 1.5 h), the latter reacts as an azomethine by a [4 + 2] cycloaddition reaction with the resulting aroylketenes. In the course of this reaction 6-aryl-3-cyanomethyl-3,4-__________________________________________________________________________________________

Synthesis of azoles and azines and their condensed derivatives based on N-cyano-S-alkylthioureas (Review)

“…With "hot" aroylketenes, generated during the thermolysis of 6-aryl-2,2-dimethyl-1,3-dioxin-3-ones, the reaction takes place at the C═N bond of the reagent, while the aroylketenes formed from 5-aryl-2,3-dihydrofuran-2,3-diones at lower temperature react through the cyano group. 2,3-Dihydro-1,3-oxazin-4-ones 30 were isolated from the reaction mixture in the first case [32], and 1,3-oxazin-4-ones 31 in the second [33]. The difference in the reactivity of the isothiourea 2 is probably due to the different temperature at which the aroylketenes are formed.…”

Direct heterocyclization of [3,4-dihydroisoquinolin-1(2H)-ylidene]acetamides with aroylketenes. Crystal and molecular structure of (Z)-3-(4a-methyl-1,3,4,4a,5,10b-hexahydrophenanthridin-6(2H)-ylidene)-4-phenylpyridine-2,6(1H,3H)-dione

“…5-Arylfuran-2,3-diones are known to undergo a thermal decarbonylation with generation of aroylketenes 1,2 which can readily participate in the intermolecular cycloaddition reactions 3,4 and can acylate weak nucleophiles to give aroylacetyl derivatives 3,5 . At the same time 5-arylfuran-2,3-diones themselves can acylate nucleophiles yielding aroylpyruvoyl derivatives under the temperatures lower than required for the process of aroylketenes generation 3,6 .…”

Acylation of the enamino tautomer of 2-azaspiro[4.5]deca-1,6,9-trien-8-ones with 5-arylfuran-2,3-diones. Crystal and molecular structure of (2Z,5Z)-3-Hydroxy-5-(6,9-dimethoxy-3,3-dimethyl-8-oxo-2-azaspiro[4.5]deca-6,9-dien-1-ylidene)-1-phenylpent-2-ene-1,4-dione

“…Thermal decarbonylation of 5-arylfuran-2,3-diones generates aroylketenes capable of reacting with active dienophiles according to the Diels-Alder pattern [1,2] and acylating weak nucleophiles with formation of aroylacetyl derivatives [1,3]. On the other hand, furandiones themselves can react with nucleophiles to produce aroylpyruvoyl derivatives at a temperature below that required for generation of aroylketenes [1,4].…”