CS196927B1 - Process for preparing 2-substituted 1-/5-nitro-2-furyl/ethylenes - Google Patents

Description

The present invention provides a process for the preparation of 2-substituted 1- (5-nitro-2-furyl) ethylenes.

The preparation of the 2-substituted 1- (5-nitro-2-furyl) ethylene derivatives has hitherto been addressed in the following five ways:

1. Condensation of 5-nitro-2-furaldehyde, its acetate, resp. acetal with alkyl heterocycles whose alkyl group has acidic hydrogens (Ueno, S., Shimogo, E., Kawasaki, T., Immaru, D., Osaki, Y., Jap., U.S. Pat. No. 71,167,790 (1971), Chem. Abstr. 74, 424949 (1971)).

2. Condensation of 5-nitro-2-furaldehyde with heteroarylacetic or phenylacetic acids and subsequent decarboxlation of the resulting product (Hirao I., Kitamura Y., Furuno M .: Nippon Kagaku Zasshi 84, 940 (1984), Chem. Abstr. 61, 14) 617 (1964).

3. Direct cyclization of reactive 3- (5-nitro-2-furyl) acrylic acid derivatives (Lanquist J.K .: English patent 1028 152 (1966), Chem. Abstr. 65, 2 273 (1966)).

4. Condensation of 2-furaldehyde in a basic medium with alkali salts of alkyl heterocycles of heterocycles and subsequent nitration of the resulting product (Breuer, H., Germany 2135 171 (1972), Chem. Abstr. 77, 5 485 (1972)).

5. Wittig reaction of 5-nitro-2-furyldehyde with heterocyclic ylides (Tanaka A., Yoshina S .: Jap. Pat. 69 13 505 (1969), Chem. Abstr. 71, 124 210 (1969)), respectively. . by the reaction of 5-nitro-2-furfurylidene phosphorans (Saikachi H., Nakamura S .:

Yakugaku Zasshi88, 110 (1968), Chem. Abstr. by 5-nitro-2-furfuryl phosphate (Jurasek A., Kovac J., Prousek J .: Chem. Zvěsti 29, 234 (1975)) with carbonyl compounds of heterocycles.

A disadvantage of these methods of preparation is the low yields of the final product. Some methods of preparation are demanding because of the synthesis of intermediates and thus the increased number of preparation steps.

The process for the preparation of the 2-substituted 1- (5-nitro-2-furyl) ethylenes of formula I is substantially eliminated by these drawbacks.

O _and M - ( ^Q ₎ -CH 3 CH-R _[L] wherein R is phenyl, 4-methylphenyl, 4-hydroxyphenyl, 4-methoxyphenyl, 2-thienyl, 2-naphthyl, wherein: bromo-1- (5-nitro-2-furyl) ethylene is treated with aromatic compounds which are substituted with electron-donating substituents such as benzene, toluene, phenol, anisole, thiophene, naphthalene under the catalytic action of aluminum chloride in an organic solvent environment such as nitrobenzene , nitromethane, carbon disulfide, 1,2-dichloroethane, dichloromethane at 0 ° C to the boiling point of the solvent.

An advantage of the process for the preparation of 2-substituted-1- (5-nitro-2-furyl) ethylenes according to the invention is higher yields than processes (1-4) and approximately the same as process (5), but it is difficult to prepare intermediates ( Shigetaka Y., Akira T., Katsumi Y .: Yakugaku Zasshi 88, 65 (1968J, Chem. Abstr. 69, 27 134 (1968); Tanaka A., Yoshina S .: Jap. Pat. 69 04, 975 (1969) , Chem., 70, 114, 996 (1969), Hirao I., Kitamura, Y .: Nippon Kagaku Zasshi 85, 506 (1964), Chem., 62, 11 756 (1965), Krkoška P., Jurášek A Advantages of the process according to the invention are the simple preparation of the intermediate 2-bromo-1- (5-nitro-2-furyl) ethylene, which is prepared from 3- {5-nitro-2- furyl) acrylic acid (Vegh D., Kovac J., Hasova B .: Collect. Czech, Chem. Commun. 41, 614 (1976)), which is commercially available.

Substituted 1- (5-nitro-2-furyl) ethylenes substituted in the 2-position by aromatic or heteroaromatic compounds have widespread use in medicine and the food industry for their high antibacterial activity and low toxicity.

The invention is illustrated but not limited by the following examples.

The organic layer was separated, washed with water, 5% potassium carbonate solution and dried with anhydrous calcium chloride. The solvent was removed in vacuo and the residue was chromatographed on Al 2 O 3. Yield 1.04g (45.5%) of 2- (4-methylphenyl) -1- (5-nitro-2-furyl) ethylene (m.p. 1.120-121 ° C, crystallized from n-heptane).

Example 3

Preparation of 2- (4-hydroxyphenyl) -1- (5-nitro-2-furyl) ethylene

0 _t N

CH = CH-1

OH

To a mixture of 2.18 g (0.01 mol) of 2-bromo-1- (5-nitro-2-furyl) ethylene, 2 g (0.015 mol) of anhydrous aluminum chloride in 10 ml of 1,2-dichloroethane at 0 ° 4.7 g (0.05 mol) of phenol in 10 ml of 1,2-dichloroethane are added with stirring. The reaction mixture was stirred at 20 ° C for 0.5 h, poured onto a mixture of 20 g of ice and 20 mL of conc. hydrochloric acid. The organic layer was separated, washed with water, 5% potassium carbonate solution and dried with anhydrous calcium chloride. The solvent was distilled off in vacuo and the residue was chromatographed on Al 2 O 3. Yield 1.33 g (57.6%) of 2- (4-hydroxyphenyl) -1- (5-nitro-2-furyl) ethylene (m.p. 208-210 ° C, crystallized from benzene).

Example 1

Preparation of 2-phenyl-1- (5-nitro-2-furyl) ethylene

To yield 2.18 g (0.01 mol) of 2-bromo-1- (5-nitro-2-furyl) ethylene, 2g (0.015 mol) of anhydrous aluminum chloride in 10 ml of dry 1,2-dichloroethane at 0 ° 3.9 g (0.05 mol) of benzene in 10 ml of 1,2-dichloroethane are added with stirring. The reaction mixture is heated at the boiling point of the solvent for 0.5 h, then poured onto a mixture of 20 g of ice and 20 ml of conc. hydrochloric acid. The organic layer was separated, washed with water, 5% potassium carbonate solution and dried with anhydrous calcium chloride. The solvent was distilled off in vacuo and the residue was chromatographed on Al 2 O 3. Yield 0.9 g (42%) of 2-phenyl-1- (5-nitro-2-furyl) ethylene (m.p. 110-111 ° C, crystallized from n-heptane).

Example 4

Preparation of 2- (4-methoxyphenyl) -1- (5-nitro-2-furyl) ethylene w //

0, N

chsch

-OOCH «

Using the procedure of Example 3, 2-bromo-1- (5-nitro-2-furyl) ethylene, 2 g (0.015 mol) of anhydrous aluminum chloride and 5.4 g (0.05 mol) of anisole are prepared. 2- (4-methoxyphenyl) -1- (5-nitro-2-kuryl) ethylene in a yield of 1.43 g (58.2 proc.) (Mp 144-145 ° C, crystallized from n-heptane).

Example 2

Preparation of 2- (4-methylphenyl) -1- (5-nitro-2-furyl) ethylene

Example 5

Q _and N

CH »CH— '' CH _S

Preparation of 2- (2-naphthyl) -1- (5-nitro-2-furyl) ethylene

To a mixture of 2.18 g (0.01 mol) of 2-bromo-1- (5-nitro-2-furyl) ethylene 2g (0.015 mol) of anhydrous aluminum chloride in 10 ml of dry 1,2-dichloroethane at 0 ° C was added at 0 ° C. with stirring 4.6 g (0.05 mol) of toluene in 10 ml of 1,2-dichloroethane are added. The reaction mixture is heated at the boiling point of the solvent for 0.5 h, then poured onto a mixture of 20 g series and 20 ml conc. hydrochloric acid.

Following the procedure of Example 3, 2-bromo-1- (5-nitro-2-furyl) ethylene, 2g (0.015 mol) of anhydrous aluminum chloride and 6.4 g (0.05 g) were prepared from 2.18 g (0.01 mol). mole) of naphthalene 2- (2-naphthyl) -1- (5-nitro-2-furyl) ethylene in a yield of 1.97 g (74.3%) (mp 102.5-104 ° C, crystallized from n-heptane) ).

Example 6

Preparation of 2- (2-thienyl) -1- (5-nitro-2-furyl) ethylene ^{AGH CH} ^ ^S ^

Following the procedure of Example 3, 2-bromo-1- (5-nitro-2-furyl) ethylene, 2 g (0.015 mol) of anhydrous aluminum chloride and 4.2 g of (2-bromo-1- (5-nitro-2-furyl)) are prepared. 0.05 mol of thiophene 2- (2-thienyl) -1- (5-nitro-2-furyl) ethylene in 1.49 g (67.6 proc.) Yield (mp 117.5-119 ° C, crystallized) from n-heptane).

Claims (1)

Process for preparing 2-substituted 1- (5-nitro-2-furyl) -ethylenes of formula I M CH 2 CH-R (i) wherein R is phenyl, 4-methylphenyl, 4-hydroxyphenyl, 4-methoxyphenyl, 2-thienyl, 2-naphthyl, characterized in that on 2-bromo-1- (5-nitro- 2-furyl) ethylene of formula (II) is treated with aromatic compounds which are substituted with electron-donating substituents such as benzene, toluene, phenol, anisole, tlofen, naphthalene under the catalytic action of aluminum chloride in an organic solvent environment such as nitrobenzene, nitromethane, carbon disulphide, 1,2-dichloroethane, dichloromethane at 0 ° C to the boiling point of the solvent.