Furan derivatives. ЬХХП. Synthesis and some properties of l-(5-nitro-2-furyl)- -2- (5-aryl-2-furyl)ethylenes

Wittig reaction has recently been applied also in the preparation of 5-nitrofuran derivatives of ethylene [1—5]. The quoted syntheses were accomplished starting either from 5-nitrofurfuryl halides which were converted into 5-nitrofurfurylidenephosphoranes and subsequent condensation of the latter with carbonyl compounds [1—4], or the intermediate phosphoranes were prepared from other furfuryl halides and these were condensed with 5-nitro-2-furaldehyde [5]. The reported yields were most of the time low and sometimes not given a t all. The present work describes the synthesis of the basic olefin-forming reagent, namely 5-nitrofurfurylphosphate (/), and its use in t h e synthesis of hitherto un­ known l-(5-nitro-2-furyl)-2-(5-aryl-2-furyl)ethylenes under the conditions of Wittig reaction as modified by Horner. This modification is known to give better yields, is simpler as to the isolation of the produced olefins and has not yet been applied in t h e synthesis of 5-nitrofuran derivatives of ethylene.