SU1133273A1 - Process for preparing 3.(2-furyl)-acrylic anhydride - Google Patents

Abstract

SUBSTANCE TO OBTAIN ANHYDRIDE 3-

Description

The invention relates to an improved process for the preparation of 3- (2-furyl) -acrylic acid anhydride, which is used as a reagent for the production of chromophore substrates of enzymes and diagnostic preparations.

A known method for producing 3- {2-uryl) -acrylic acid anhydride by reacting 3- (2-fur 21) -acrylic acid with an excess of acetic anhydride at 110 C. The yield of the desired product is 73% I.

The disadvantages of the known method are the necessity of carrying out the process at a temperature higher than 100 ° C, which complicates the process in the technological aspect and requires additional energy consumption, the use of a large excess of condensing agent (acetic anhydride {Ida) and a relatively low yield of the target product,

The aim of the invention is to simplify the process and improve the yield of the target product.

The goal is achieved in that according to the method of producing 3- (2-furyl) -acrylic acid anhydride by the interaction of 3- (2-furyl) -acrylic acid with acid anhydride, dialkylpyrocarbonate is used as the acid anhydride and the process is carried out in an aprotic organic solvent medium at at room temperature in the presence of a tertiary amine at a molar ratio of 3- (2-furyl) acrylic acid to dialkylpyrocarbonate 1: 0.5-0.57,

Ethyl acetate is preferably used as the aprotic organic solvent.

According to a known method, the formation of a target anhydrite occurs as a result of a reversible reaction, and in this case the ratio of initial reagents plays a decisive role, as the equilibrium shifts towards the formation of the target product using a large excess of condensation agent (acetic anhydride). The proposed method is based on a non-equilibrium process, since the intermediate derivative of carbonic acid formed as a result of the reaction along with the target product disintegrates at ordinary temperature to alcohol and carbon dioxide. In this case, the excess of the condensing agent — dialkylpyrocarbonate — is minimal and approaches the theoretical amount (0.5 M pyrocarbonate per 1 M of the original acid). The excess reagent introduced into the reaction may be spent on side processes (hydrolysis with moisture of a solvent, etc.) and may partially remain unchanged, which is undesirable in principle.

The process chemistry (and economic feasibility) dictates a striving for a minimal excess of pyrocarbonate. This is the boundary condition for the ratio of initial reagents to

The proposed process for the preparation of 3- (2-furyl) -acrylic acid anhydride.

Example 1. The preparation of furilacrylic anhydride from di-tert-butyl pyrocarbonate.

A solution of 3.0 g (21 mm) of 3- (2-furyl) acrylic acid, 2.5 ml (11 mm) of di-tert-butyl pyrocarbonate (1: 0.52 M) and 0.4 ml of pyridine in 15 ml of ethyl acetate stir until the CQj clears (5-7 h), evaporated in vacuo at 40 ° C, the crystalline residue is dissolved in ether, the solution is filtered, evaporated if necessary, and

the residue is crystallized from hexane. The precipitate is filtered off, washed with hexane, dried in vacuum over and get 2.5 g (92%) of anhydride of furilacrylic acid with so pl.

76-77 C. RI 0.61 (Silufol UV-254 plates, solvent system carbon tetrachloride - cyclohexane methyl ethyl ketone 3: 2: 2). Spot detection: visually under a UV lamp, hydroxylamine - ferric chloride.

IR spectrum, kWh: 1780, 1700 (anhydride group).

PRI and M e p 2. Anhydride 3- (2-furyl) -acrylic acid from diethylpyrocarbonate.

A solution of 3.0 g (21 mM) of 3- (2-furyl) acrylic acid (1: 0.57 M), 1 ml of N-methylmorpholine and 2 ml (12 mM) of diethylpyrocarbonate in 15 mp of ethyl acetate is stirred at 20 ° C until termination CIr (about 5 h), evaporated in vacuo. The residue is dissolved in 20 ml of ether, 0.5 g of activated carbon is added, the solution is filtered,

the filtrate is evaporated and the residue is crystallized from petroleum ether. The crystalline precipitate on the filter is washed with hexane, dried and get

one

2.3 g (84%) of the desired product with so pl. 76-77 ° C, all characteristics identical to the product of example 1 ..

Example 3. Anhydride of 3- (2-furyl) -acrylic acid from diisopropylpyrocarbonate.

The reaction is carried out analogously to example 2 with 2 mp of pyrocarbonate (1: 0.5 M) in 1 MP of triethylamine. After the usual treatment, 2.4 g (88%) of the desired product are obtained with a mp. 76-77 C.

PRI me R 4. Obtaining furyl acrylic acid anhydride from di-tert-butyl pyrocarbonate in dimethylformamide.

A solution of 3.0 g of furilacrylic acid, 2.5MP di-tert-butyl pyrocarbonate and 1.5 MP of pyridine in 10 ml of dimethylformamide is stirred until termination;

CO separation (about 1 hour), diluted with 50 MP of ethyl acetate, washed with water (2 x 25 mL), 5% hydrochloric acid, saturated solution

5 NaCj and dried. The solvent is removed in vacuo, the residue is dissolved in ether, the solution is filtered, evaporated, the crystalline residue is triturated in hexane, the precipitate is filtered, washed with hexane and dried. Obtain 2.3 g (84%) of the desired product with so pl. 76-77 C, Rf 0.76.

Thus, the proposed method allows to eliminate the process at elevated temperature and thereby simplify it, as well as to increase the yield of the target product to 84-88%.

Claims (1)

METHOD FOR PRODUCING 3- (2-FURYL) -ACYRIC ACID ACID by reacting 3- (2-furyl) -acrylic acid with acid anhydride, characterized in that, in order to simplify the process and increase the yield of the target product, dialkyl pyrocarbonate and the process is carried out in an aprotic organic solvent at room temperature in the presence of a tertiary amine with a molar ratio of 3- (2-furyl) -acrylic acid to dialkyl pyrocarbonate 1: 0.5-0.57. oo 00 ke m 00>