SU888496A1 - Process for producing 2,2-dimethoxy-4,4-diphenyl-5-substituted-1,3,2-oxazaphosph-2-enes - Google Patents

Description

The invention relates to the chemistry of organophosphorus compounds, specifically to a method for producing 2,2-dimethoxy-4,4-diphenyl'5-substituted-1,3,2-oxazaphosphol-2-enes of the general formula

where R —C ₆ H ₅ —or —C (CH ₃ ) ₃ .

These compounds can be used as intermediates in the synthesis of physiologically active substances.

A known method of producing oxazaphospholenes by the interaction of dimethylisocyanatophosphite with nitrile of trimethylpyruvic acid [1].

There is also a method of producing oxazaphosph.olens by the interaction of diethylisocyanatophosphite with aldehydes [2].

The disadvantages of this method include hydrolytic instability of the target products, as well as their low yield (8-13%). However, 2,2-dimethoxy-4,4-diphenyl-5-substituted-1,3,2-oxazaphosphol-2-enes and the method for their preparation are not described in the literature and are new.

The aim of the invention is to develop an affordable method for producing 2,2-dimethyl si-4,4-diphenyl-5-substituted-1,3,2-oxazaphosphol-2-enes.

The goal is achieved by implementing the proposed method for producing 5 2,2-dimethoxy-4,4-diphenyl - 5 - substituted

1,3,2-oxazaphosphol-2-enes of the general formula (1), which consists in the fact that dimethyl diphenylmethyleneamidophosphite of the formula _{) o} (CH ₃ O) ₂ P — N = C (C ₆ H ₅ ) ₂ is reacted with nitrile α -ketocarboxylic acid of the general formula RC (O) CN, where R —C ₆ H ₅ —or —C (CH ₃ ) ₃ , at an equimolar ratio of the reactants in an inert gas atmosphere at 35–45 ° С.

In the described method, for the first time, the reaction of dimethyl pdphenylmethyleneamidophosphite with nitriles of a-ketocarboxylic acids was carried out and stable oxazaphospholenes were obtained as individual compounds. These are the first data on the reactions of dimethyldiphenyl methyleneamidophosphites with carbonyl compounds activated by electron withdrawing substituents. The interaction begins with the nucleophilic attack of the phosphorus atom on the carbon of the carbonyl group, followed by phosphonate-phosphate rearrangement π by the closure of the five-membered cycle.

The optimal conditions for the implementation of the method are the use of equimolar amounts of the starting reagents; the use of an excess of one or another reagent complicates the purification of the target products); carrying out the reaction in a stream of dry gas to prevent oxidation and hydrolysis of the final products; the implementation of the method at a temperature of 35-45 ° C (lowering this temperature slows down the reaction, and an increase leads to the decomposition of dimethyldiphyl 11-yl methyleneamidophosphite) ·.

When using the proposed method for producing substituted oxazaphospholenes, the following efficiency is ensured:

the possibility of synthesizing substituted oxazaphospholenes based on dimethyldiphenylmethyleneamidophosphites used for the first time in reactions with nitriles of a-ketocarbopic acids;

simplicity of the technology of the method (the method is carried out in one stage), reliable reproduction of the results, availability of starting reagents, good yield of products (47-50%).

The structure of the obtained compounds is confirmed by the data of elemental analysis, and K - and PMR spectroscopy.

The IR spectra contain (V, cm- ¹ ) bands: 1040 (Р – О – С), 1620, 3070 (С ₆ Н ₅ ), there are no absorption bands characteristic of С = О, C = N, Р = О groups. The PMR spectrum of 2,2-dimethyl-4,4-diphenyl-5 cyano-5-phenyl - 1,3,2 - oxazaphosphol-2-ene contains signals (CF ₃ COOH, 60 MHz): ύ (OCH ₃ ) 3 , 89 and 4.09 [3 1рн. 12 Hz], complex multiplet of phenyl protons δ 6.9, 7.50 ppm.

Preparation of 2,2-dimethoxy-4,4-diphenyl5-cyano-5-phenyl-1,3,2-oxazaphosphol2-ene.

5.9 g (0.045 mol) of benzoyl formic acid nitrile are added dropwise to 12.3 g (0.045 mol) of dimethyldiphenylmethyleneamidophosphite in an argon atmosphere at 40–45 ° С. After a day, crystals precipitate in the reaction mixture and are washed repeatedly with ether (47%), mp. 164 ° C.

Found,%: C 67.97; H 5.29; P 7.85.

C23H21N2O3P.

Calculated,%: C 68.31; H 5.19; P 7.67.

Preparation of 2,2-dimethoxy - 4,4 - diphenyl ⁵ 5-cyano-5-tert-butyl-1,3,2-oxazaphosphol-2ene.

To 2.4 g (0.008 mol) of dimethyldiphenylmethyleneamidophosphite, 0.98 g (0.008 mol) of trimethylpyruvic acid 10 nitrile nitric acid are added dropwise in an argon atmosphere under

35-40 ° C. Crystals are isolated from the reaction mixture, which are washed repeatedly with ether (50%), mp. 138 ° C.

Found,%: C 65.52; H 6.50; P 7.62.

C2iH2sN2O ₃ P.

Calculated,%: C 65.62; H 6.51; P 8.07.

Claims (2)

The optimal conditions for the implementation of the method are the use of equimolar amounts of the initial reagents (the use of an excess of one or another reagent makes it difficult to purify the target products); carrying out the reaction in a stream of dry gas to prevent oxidation and hydrolysis of the final products; carrying out the process at a temperature of 35-45 ° C (a decrease in this temperature slows down the reaction, and an increase leads to the decomposition of dimethyldifimeylmethylene amidophosphite) -. When using the proposed method for producing zlaften oxazaphospholeps, the following efficiency is ensured; the possibility of synthesizing substituted oxazaphospholenes based on dimethyldiphenylmethylene amidophosphites, used for the first time in reactions with nitrites of a-ketocarbopic acids; simplicity of the method (method is implemented in one stage), reliable reproduction of the results, availability of initial reagents, good yield of products (47-50%). The structure of the obtained compounds is confirmed by elemental analysis, IR and PMR spectroscopy. In the IR spectra there are bands (V, cm-1): 1040 (P-O-C), 1620, 3070 (CbNb), there are no absorption bands characteristic of the C O, C N, P 0 groups. In the PMR spectrum of 2,2-dimethyl-4,4-diphenyl-5 cyano-5-phenyl-1,3,2-oxazaphosphol-2-ene, there are signals (CP3COOH, 60 MHz): S (OCH3) 3.89 and 4.09, 3 IPPL 12 Hz, multiplet of phenyl protons b 6.9, 7.50 ppm. Production of 2,2 - dimethoxy - 4,4 - diphenyl5-cyano - 5 - phenyl - 1,3,2 - oxazaphosphol2-ene. 5.9 g (0.045 mol) of benzoyl formic acid nitrile in an atmosphere of argon at 40-45 ° C are added dropwise to 12.3 g (0.045 mol) of dimethyldiphenylmethylene amidophosphite. After one day, crystals fall out in the reaction mixture, which are washed several times with ether (47%), mp. 164 ° C. Paydeno,%; C, 67.97; H 5.29; R 7.85. CzsHaiNsOgP. Calculated,%: C 68.31; H 5.19; R 7.67. Preparation of 2,2-dimethoxy-4,4-diphenyl-5-cyano-5-tert-butyl-1, 3,2-oxazaphosphol-2ene. To 2.4 g (0.008 mol) of dimethyldiphenylmethylene amidophosphite, 0.98 g (0.008 mol) of trimethylpyruvic acid nitrile in an atmosphere of argon at 35–40 ° C are added dropwise. Crystals were separated from the reaction mixture and washed repeatedly with ether (50%), m.p. 138 ° C. Found,%: C 65.52; H 6.50; R 7.62. С21Н25М20зР. Calculated,%: C 65.62; H 6.51; R 8.07. The claims of the method for producing 2,2-dimethoxy-4,4-diphenyl-5-substituted - 1,3,2-oxazaphosphol 2 -enes of the general formula (eHaU where R is CeHs-or -C (CH3) s, that dimethyldife 11 orm. of m of etheram of iodophosphite (CH3O) (CbH5) 2 is reacted with a-ketocarboxylic acid nitrile of general formula RC (0) CN, where K. has the indicated values, at an equimolar ratio of reagents in an inert gas atmosphere at 35-45 ° C. Sources of information taken into account during the examination 1.Konovalova I.V. and others. On the interaction of dialkylphosphorous acid isocyanates t with nitrile trimethylpyruvic acid. -XOX, 1978, 48, No. 5, pp. 1013. 2. Tarasov, R.I., et al. The product of 1,3-cycloaddition of p-nitrobenzaldehyde to isocyanatodiethylphosphite and its hydrolysis in solution.- JOH 1980, 50, No. 3, p. 538.