HETERODIENE SYNTHESES .20. 4-ARYLIDENE-5-PYRAZOLONES AND YNAMINES - [2+2]CYCLOADDITION FOLLOWED BY ELECTROCYCLIC RING-OPENING, IN COMPETITION WITH A [4+2]CYCLOADDITION - INFLUENCE OF THE SUBSTITUENTS ON THE INTERMEDIATE

被引：7

作者：

DESIMONI, G ^{[1
]}

RIGHETTI, P ^{[1
]}

TACCONI, G ^{[1
]}

OBERTI, R ^{[1
]}

机构：

[1] CNR,CTR STUDIO CRISTALLOG STRUTT,PAVIA,ITALY

来源：

JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1 | 1979年 / 04期

关键词：

D O I：

10.1039/p19790000856

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

4-Arylidene-5-pyrazolones (1) react with NN-diethylaminomethylacetylene to give a mixture of pyrano[2,3-c]-pyrazoles (3), in accordance with a [4 + 2]cycloaddition, and 4-(3-aryl-1-diethylamino-2-methylpropenylidene)-pyrazol-5- ones (5) which are formed by electrocyclic ring opening of the [2 + 2]cycloadducts (4). The configuration of the open-chain compounds (5) permits the deduction of that of the originally formed cyclobutene adducts. The reason for the choice between a [4 + 2] and a [2 + 2]cycloaddition can be rationalized in terms of the effect of both the substituents and the configuration of the substrate.

引用

页码：856 / 862

页数：7

共 36 条

[1]

BROUWER AC, 1976, TETRAHEDRON LETT, P209

[2]

BUSING WR, 1962, ORNLTM305 REP

[3] CRYSTAL AND MOLECULAR-STRUCTURE OF UNSOLVATED MU-OXO-BIS-[N,N'-ETHYLENEBIS(SALICYLALDIMINATO)IRON (III)] [J].