A study of 2‐aminofurans

Abstract

Catalytic reduction of 2‐nitrofurans 2 gives low yields of 2‐aminofurans 1 which are not isolated but are trapped using ethyl ethoxymethylenecyanoacetate (6) or ethoxymethylenemalononitrile (7). In these reactions 2‐aminofuran (1a) behaves like a dieneamine with substitution occurring at position 5 of the ring. When the 5‐position is substituted reaction takes place at position 3 and thermal cyclisation of the product gives furo‐[2,3‐b]pyridine derivatives 16. An AM1 calculation of the properties of 2‐aminofuran (1a) is reported and the results are consistent with observed properties.

Application of the Gould–Jacobs reaction to 4-amino-2,1,3-benzoselenadiazole

“…Amine 4 obtained by this procedure is stable enough and can be stored under air for a long time without any decomposition ((hetero)aromatic amines are generally unstable in air). 18 A disadvantage of this synthesis is the use of not so readily available 2,6-dinitroaniline (1), which was replaced by the already mentioned easily available 4-nitrobenzoselenadiazole 5. The latter was reduced with stannous chloride dihydrate under the same reaction conditions as described for dinitroaniline 1 to afford dihydrochloride 2 in 68% yield.…”

“…Nonetheless, yields of the final amine 4 were unsatisfactorily low (15e20%). One of the possible explanations is that the decay of triamine 3 occurred during the hydrogenation, which took more than 24 h. 18 Next dinitroaniline 1 was subjected to reduction with stannous chloride dihydrate in concentrated hydrochloric acid according to Avendano et al 19 with slight a modification in the procedure to yield free triamine 3. The triamine was liberated from its dihydrochloride 2 by sodium hydroxide solution (Scheme 1).…”

Nitro and aminobenzimidazoles

“…2). Amines and especially heterocyclic ones are readily oxidized in air which complicates their study (Lythgoe et al, 1993). 5( 6)-Aminobenzimidazoles were found to form stable hydrates (Kada et al, 1974).…”

13C and 15N NMR spectra of aminobenzimidazoles in solution and in the solid state

“…Notice that these compounds are readily oxidized under open atmosphere similarl to related compounds, making their study difficult. [21] Results and Discussion…”