Nitroimidazoles: Part VIII. 2-Amino-1-methyl-5-nitroimidazoles & derivatives

Abstract

Treatment of 1-methyl-2-methylsulphonyl-5-nitroimidazole (3) with liquid ammonia gives 2-amino-l-methyl-5-nitroimidazole(2). With sodamide and 3, the major product is the sulphone(4). 2 is transformed by isocyanates into ureas(5a-c), while with 2-chloroethyl isocyanate, imidazolidinone (6) and aminooxazolinone (7) are obtained. 2 is less reactive towards isothiocyanates and gives under forcing conditions, thioureas (8a, b) and guanidines (9a, b). Amides (lOa-c) are obtained from 2 by acylation and lOd-g from sulphone(3) by displacement reactions as also sulphamides(lla-c). Cyclic anhydrides and 2 lead to imides (13-15). 2 is transformed into schiff bases (16a-k), some of them being reduced by sodium borohydride to aralkyl amines (17a-c). The ethoxymethylene derivative (18) of 2 is transformed into a large number of formamidines (19a-r), (20a-c) and 21, some of them being further converted into the dichloroacetyl derivatives (22a-c). Reaction of 18 with sodium borohydride affords the ethoxymethylamine (23b) and methylamine derivative (23a). The latter is available from 2 along with dimethylamine (23c) by alkylation with methyl iodide. A less satisfactory route for 23a and 23c is displacement of sulphone group from 3 by appropriate amine. Analogous displacements on 3 provide the derivatives 23d, e and 24. The product from the reaction of 3 with sodium azide is the azido derivative (25). The aziridine (27) undergoes iodide-catalysed ring opening to form 29a and does not rearrange to the imidazoline (28). The amirioethanol derivative (29b) results from 27 by an acid-catalysed reaction.