Ring transformations of 5-nitropyrimidine via inverse diels-alder reactions

✍ Scribed by Valery N. Charushin; Henk C. van der Plas

• Publisher: Elsevier Science
• Year: 1982
• Tongue: French
• Weight: 214 KB
• Volume: 23
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)87756-4

✦ Synopsis

SuImkWyz 5-Nitropyrlrmdme undergoes lIlverse Diels-Alder cycloaddltlons w1t.h ketene-N,N-, -O,Cacetals and enanunes resulting 111 pyrl&ne derlvatlves. The 'H NMR evidence for the I-N,N-diethylmopropyne cycloadduct formation 1s presented mng transformations of s-tetrazmes proceeding via an inverse electron demand Diels-Alder reaction followed by a retrograde process are well established and have recently been rev=ewed.2 Also anumber of reports on slrmlar ring transfonnatlons of 1,2,4-triazmes have appeared m the last decade. 3

However, no example of a Diels-Alder cycloaddltlon on the pyrlnudlne ring has been reported so far.

In this cormnunlcatlon we wish to show that the pyrlrmdlne ring when activated by a strong electron acceptor as the nltro group 1s able to undergo [4+21 cycloaddltlon reactlons 111 which electron-rich ethylenes or acetylenes react as a dlenophlle and the pyrlrmdlne ring as an electron-deflclent diene.