4-FURANAMIDES AND METHOD FOR THE PRODUCTION THEREOF

Abstract

The present invention relates to 4-furanamides of the general formula (I) and to a method for preparing said compounds and to the use thereof as important precursors for the synthesis of agrochemical and pharmaceutical active ingredients.

##STR00001##

Claims

1. A method for preparing a compound of formula (I) ##STR00006## in which R.sup.1 is COO(C.sub.1-C.sub.4)-alkyl, R.sup.2 is CF.sub.3, CF.sub.2H, C.sub.2F.sub.5, CF.sub.2Cl, CCl.sub.3, comprising reacting the compound of formula (II) ##STR00007## in which R.sup.3 is halogen and R.sup.1 has the definitions stated above, in the presence of a compound of formula (III) R.sup.2CONH.sub.2, a Cu(I) salt, an amine, a base and ascorbic acid.

2. The method according to claim 1, wherein the definitions of the radicals of the compound of formulae (I), (II) and (III) are as follows: R.sup.1 is COOCH.sub.3, COOC.sub.2H.sub.5, R.sup.2 is CF.sub.3, CF.sub.2H, R.sup.3 is Br, Cl.

3. The method according to claim 1, wherein the definitions of the radicals of the compound of formulae (I), (II) and (III) are as follows: R.sup.1 is COOCH.sub.3, R.sup.2 is CF.sub.3, R.sup.3 is Br.

4. The method according to claim 1, wherein the reaction is carried out at 80-90° C.

5. The method according to claim 1, wherein the solvent is dioxane.

6. The method according to claim 1, wherein the copper salt is Cu Br.

Description

DESCRIPTION OF THE METHODS AND INTERMEDIATES

EXAMPLES

[0047] The present invention is elucidated in more detail by the examples which follow, without restricting the invention to these examples.

Method of Measurement

[0048] The products were characterized by .sup.1H-NMR.

Example 1

Methyl 4-[(2,2,2-trifluoroacetyl)amino]furan-2-carboxylate

[0049] 200 ml of dry 1,4-dioxane, a solution of 100 g (0.48 mol) of methyl 4-bromofuran-2-carboxylate (99%) in 100 ml of dry 1,4-dioxane and a solution of 63.2 g (0.53 mol) of trifluoroacetamide (95%) in 100 ml of dry 1,4-dioxane are initially charged in a dry 1000 ml double jacket vessel, equipped with a mechanical stirrer, at 22° C. under nitrogen. To this are added 7.1 g (0.048 mol) of copper(I) bromide (98%), 6.4 g (0.036 mol) of ascorbic acid (99%) and 134.8 g (0.96 mol) of finely powdered potassium carbonate (99%). The inlet opening is rinsed with 90 ml of dry 1,4-dioxane. The vessel is sealed and nitrogen is passed through the stirred suspension for 15 minutes. The reaction mixture is heated to 83-85° C. On reaching a temperature of ca. 70° C., a solution of 8.5 g (0.058 mol) of trans-N,N′-dimethylcyclohexane-1,2-diamine (97%) in 8.5 g of dry 1,4-dioxane are added. The mixture is then stirred at 83-85° C. for 3 hours. The mixture is then cooled to 15° C. and added in portions to a mixture of 250 ml of ethyl acetate and 560 g of hydrochloric acid (10%) cooled to 10° C. The reaction vessel is rinsed with 100 ml of ethyl acetate and 40 ml of hydrochloric acid (10%). The biphasic mixture is stirred at 20° C. for 30 minutes, then the phases are separated. The aqueous phase is re-extracted with 150 ml of ethyl acetate. The combined organic phases are washed twice with 300 ml each time of hydrochloric acid (1%). At a jacket temperature of 50° C. and at 200 mbar, ca. 500 ml of solvent are distilled off from the organic phase. Then, 250 ml of toluene are added, whereupon product may precipitate. Ca. 150 ml of solvent are distilled off at 50° C. jacket temperature and down to 115 mbar pressure. 50 ml of methanol are added to the residue, whereupon a clear solution forms at 50° C. Ca. 100 ml of solvent are distilled off therefrom at 50° C. and 115 mbar, whereupon product crystallizes out. Finally, the mass of the residue is ca. 200 g. The residue is cooled to 0° C. over 2 hours and stirred for 1 hour. The solid is filtered off and washed with 3 100 ml portions of cold toluene. The moist product is dried at 40° C. and 10 mbar.

[0050] This gives 72 g of methyl 4-[(2,2,2-trifluoroacetyl)amino]furan-2-carboxylate (99%) in 62% yield.

[0051] .sup.1H-NMR (600 MHz, DMSO): δ 3.85 (s, 3H), δ 7.30 (s, 1H), δ 8.32 (s, 1H), δ 11.80 (br s, 1H)

[0052] .sup.13C-NMR (600 MHz, DMSO): δ 52.05 (s), δ 111.89 (s), δ 112.79, 114.69, 116.59, 118.5 (qa), δ 124.60 (s), δ 137.21 (s), δ 142.40 (s), δ 153.54, 153.79, 154.04, 154.29 (qa), δ 158.04 (s).