Synthesis and some transformations of 5-(N-tosylaminomethyl)furfuryl alcohols

Abstract

Preparative methods were developed for the synthesis of 5-(N-tosylaminomethyl)furfuryl alcohols, and their behavior during the action of acidic catalysts was studied. It was established that the furan ring of these compounds is stable in the presence of orthophosphoric acid in glacial acetic acid and that their hydroxyl and N-tosylaminomethyl groups are involved in the transformations.Among the various furan derivatives furan alcohols (furylmethanols), which are widely used in fine organic synthesis, are of great interest. There are two main transformation paths for these compounds, i.e., with retention of and with opening of the furan ring.One transformation of the first type often encountered in the literature is the self-condensation of furylmethanols, leading to the formation of symmetrical difurylmethane structures [1][2][3][4].The reactions of furan alcohols taking place with opening of the heterocycle have found considerably wider application. Numerous papers have been devoted to intramolecular Diels-Alder reactions in which the furan acts as 1,3-diene [5, 6]. Such approaches have been used actively for the construction of the carbocyclic frameworks of natural compounds and their synthetic analogs [7,8] and also for the formation of condensed heterocyclic systems [9].The oxidative opening of the furan ring in 2-furylmethanols (the Akhmatovich reaction) has been used successfully in the synthesis of heterocycles [10][11][12][13]. The reaction products are derivatives of pyranoneconvenient precursors for the production of sugars [14] and various biologically active compounds [15][16][17][18][19].Examples of the protolytic opening of the furan ring are not so numerous, and this is probably explained by the well-known acidophobic nature of furan compounds and also by the possibility of self-condensation of furfuryl alcohols and the formation of difurylmethane structures [1,3,5]. With the fortuitous choice of conditions, however, the transformation provides a convenient method for the synthesis of heterocyclic systems [20].