RU2254339C1 - Method for preparing 2,2-dimethyl-4-alkoxy-5,5-dimethyl-1,3,2-oxazasilols - Google Patents

Abstract

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention describes a method for preparing substituted 1,3,2-oxazasilols of the general formula:

wherein R is C₂H₅, i-C₃H_7, C₄H₉. Method involves interaction of alkyl-(2-methyl-2-hydroxy)-propaneimidate with dimethyldichlorosilane in the presence of triethylamine in dehydrated benzene medium and in the mole ratio alkyl-(2-methyl-2-hydroxy)-propaneimidate : dimethyldichlorosilane : triethylamine = (1-1.05):(1-1.01):(2.1-2.2), respectively, at temperature 10-15°C. Invention provides expanding assortment of chemical compounds and preparing new substituted 1,3,2-oxazasilols with the yield 65%, not less.

EFFECT: improved method for preparing.

3 ex

Description

The invention relates to the chemistry of silicon-containing organic compounds, and in particular to a new method for producing substituted 1,3,2-oxazasilol-3-ins, of the general formula

where R = C ₂ H ₅ , iC ₃ H ₇ , C ₄ H ₉ ;

which are new in structure silicon-containing heterocyclic compounds and can serve as starting materials in the preparation of biologically active compounds for the needs of medicine and agriculture.

A known method of the interaction of C-phosphorylated imidates with dimethyl dichlorosilane in an inert solvent (diethyl ether, benzene) at 18-25 ° C in the presence of triethylamine. As a result, N-silicon-containing C-phosphorylated imidates were obtained [V.E. Shishkin, E.V. Mednikov, E.V. Isakova, B.I. No. Zhokh, 1997, v. 67, issue 7, p. 1219-1220.

The author did not find any substances similar to the synthesized structure in the patent and scientific literature.

The objective of the invention is to develop a one-step method for the synthesis of 2,2-dimethyl-4-alkoxy-5,5-dimethyl-1,3,2-oxazasilines.

The technical result is the expansion of the arsenal of chemical compounds and the production of new substituted 1,3,2-oxazasilines with a yield of at least 65%.

The technical result is achieved by the development of a new method for producing 2,2-dimethyl-4-alkoxy-5,5-dimethyl-1,3,2-oxazasilines of the formula

where R = C ₂ H ₅ , iC ₃ H ₇ , C ₄ H ₉ ,

consisting in the interaction of alkyl (2-methyl-2-hydroxy) propanimidate with dimethyldichlorosilane in the presence of triethylamine in anhydrous benzene medium and with a molar ratio of reactants alkyl (2-methyl-2-hydroxy) propanimidate: dimethyldichlorosilane: triethylamine (1-1.05: 1-1.01: 2.1-2.2), respectively, and a temperature of 10-15 ° C.

The chemical scheme of the proposed method for producing 2,2-dimethyl-4-alkoxy-5,5-dimethyl-1,3,2-oxazasilines

где R=C₂H₅, i-C₃H₇, C₄H₉.

where R = C ₂ H ₅ , iC ₃ H ₇ , C ₄ H ₉ .

When choosing a solvent for the reaction of dimethyldichlorosilane with alkyl (2-methyl-2-hydroxy) propanimidate, we took into account the following requirements: creating a homogeneous reaction mass, maintaining the required temperature and inertness with respect to the reacting components. Benzene meets all these requirements, all reagents are well soluble in it, it is possible to lower the temperature to 10-15 ° C, and it is also absolutely inert with respect to the reagents. It should be noted that the triethylamine hydrochloride formed during the reaction is insoluble in benzene, which also determines its use as a solvent.

At the initial moment of interaction, it is necessary to maintain the temperature to 10-15 ° C, since the reaction is accompanied by a thermal effect, and also this temperature helps to reduce the formation of resins and, accordingly, increase the yield of the target product.

Alkyl (2-methyl-2-hydroxy) propanimidate and dimethyldichlorosilane are taken in an equimolar ratio, since an excess of hydroxyimidate can lead to the formation of linear products, and an excess of dimethyldichlorosilane leads to the formation of oligomers, which can lead to a decrease in the formation of substituted 1,3,2 -oxazasilol.

Triethylamine is supplied in a small excess in order to completely bind the hydrogen chloride formed during the reaction.

The method is as follows.

For the synthesis of 2,2-dimethyl-4-alkoxy-5,5-dimethyl-1,3,2-oxazasilines, dimethyldichlorosilane dissolved in anhydrous benzene at a temperature of 10-15 ° C was added dropwise with stirring an alkyl mixture (2- methyl 2-hydroxy) propanimidate and triethylamine, also dissolved in dried benzene, with a molar ratio of the reactants alkyl (2-methyl-2-hydroxy) propanimidate: dimethyldichlorosilane: triethylamine (1-1.05: 1-1.01: 2 , 1-2.2). The synthesis was carried out for 50-60 minutes After that, the temperature of the reaction mixture was raised to room temperature, triethylamine hydrochloride was filtered off, and the solvent was distilled off from the filtrate in a vacuum of a water-jet pump. The final purification was carried out by column adsorption chromatography on silica gel grade μLC 5/40. Product purity was monitored by thin layer chromatography on Silufol plates. The yield of 2,2-dimethyl-4-alkoxy-5,5-dimethyl-1,3,2-oxazasilol was not less than 65%. Identification of the synthesized compounds was carried out according to molecular refraction, IR, mass spectroscopy. For a better understanding of the essence of the proposed technical solution, specific examples of syntheses are given.

Example 1. 2,2-Dimethyl-4-ethoxy-5,5-dimethyl-1,3,2-oxazasilol.

2.1 (0.0162 mol) of dimethyldichlorosilane dissolved in 50 ml of anhydrous benzene was charged into a reactor equipped with a stirrer and a thermometer. Then, 2.09 g (0.016 mol) of ethyl (2-hydroxy-2-methyl) propanimidate and 3.4 g (0.0336 mol) of triethylamine dissolved in 70 ml of benzene were added dropwise. The synthesis was carried out at a temperature of the reaction mixture of 10 ° C. The reagent ratio is ethyl (2-hydroxy-2-methyl) propanimidate: dimethyldichlorosilane: triethylamine (1: 1.01: 2.1). After 50 minutes, the temperature of the reaction mixture was raised to room temperature, the precipitated triethylamine hydrochloride was filtered off, benzene was distilled off from the filtrate in a vacuum of a water-jet pump. Purification of the obtained product was carried out by column adsorption chromatography on silica gel, grade μLС 5/40, eluent: diethyl ether: methanol (1: 3, v / v). Yield 69%, n ²⁰ _D 1.4415, d ²⁰ ₄ 1.0013, MR _D 49.30, calc. 50.01, R _f 0.42. IR spectrum, ν, cm ^-1 : 810 [Si (СН ₃ ) ₂ ], 1043 (CO-Si), 1675 (C = N), 1175 (С-О-С), 1345 [С (СН ₃ ) ₂ ]. Mass spectrum (70 eV), m / z (I,%): 187 (12.4) [M] ⁺ , 172 (31.6) [M-CH ₃ ] ⁺ , 142 (10.1) [MC ₂ H ₅ O] ⁺ , 129 (4.5) [M-C ₃ H ₇ O] ⁺ .

Example 2. 2,2-Dimethyl-4-isopropoxy-5,5-dimethyl-1,3,2-oxazasilol.

3.3 g (0.023 mol) of isopropyl (2-hydroxy-2-methyl) propanimidate and 4.4 g (0.044 mol) of triethylamine were added dropwise to 2.8 g (0.022 mol) of dimethyldichlorosilane dissolved in 50 ml of anhydrous benzene. dissolved in 80 ml of benzene. The reagent ratio isopropyl (2-hydroxy-2-methyl) propanimidate: dimethyldichlorosilane: triethylamine (1.05: 1: 2.2). The synthesis was carried out at a temperature of 15 ° C. After 60 minutes, the temperature of the reaction mixture was raised to room temperature, the precipitated triethylamine hydrochloride was filtered off, benzene was distilled off from the filtrate in a vacuum of a water-jet pump. Purification of the obtained product was carried out by column adsorption chromatography on silica gel, grade μLС 5/40, eluent: diethyl ether: methanol (1: 3, v / v). Yield 67%, n ²⁰ _D 1.4847 d ²⁰ ₄ 1.0249, MR _D 52.95, calc. 53.05, R _f 0.35. IR spectrum, ν, cm ^-1 : 825 [Si (СН ₃ ) ₂ ], 1050 (CO-Si), 1675 (C = N), 1175 (С-O-С), 1345 [С (СН ₃ ) ₂ ]. Mass spectrum (70 eV), m / z (I,%): 201 (15) [M] ⁺ , 186 (3.4) [M-CH ₃ ] ⁺ , 158 (9.1) [M-C ₃ H ₇ ] ⁺ , 145 (8.5) [M-C ₃ H ₇ O] ⁺ .

Example 3. 2,2-Dimethyl-4-butoxy-5,5-dimethyl-1,3,2-oxazasilol.

5.1 g (0.0354 mol) of butyl (2-methyl-2-hydroxy) propanimidate and 7.2 g of triethylamine dissolved in 100 were added dropwise to 4.5 g (0.035) of dimethyldichlorosilane dissolved in 45 ml of benzene. ml of benzene. The synthesis was carried out at a temperature of 12 ° C. The reagent ratio of butyl (2-hydroxy-2-methyl) propanimidate: dimethyldichlorosilane: triethylamine was (1: 1.01: 2.1). After 55 minutes, the reaction mixture was heated to 45 ° C in order to complete the reaction. After the reaction mixture was cooled to room temperature, the precipitated triethylamine hydrochloride was filtered off, benzene was distilled off from the filtrate in a vacuum of a water-jet pump. Purification of the obtained product was carried out by column adsorption chromatography on silica gel, grade μLC 5/40, eluent-diethyl ether: methanol (1: 3, v). Yield 65%, n ²⁰ _D 1.4554, d ²⁰ ₄ 1.0291, MR _D 59.02, calc. 59.77, R _f 0.35. IR spectrum, ν, cm ^-1 : 824 [Si (СН ₃ ) ₂ ], 1045 (CO-Si), 1670 (C = N), 1125 (С-О-С), 1340 [С (СН ₃ ) ₂ ]. Mass spectrum (70 eV), m / z (I,%): 215 (5.08) [M] ⁺ , 200 (34) [M-CH ₃ ] ⁺ , 186 (3.1) [M-C ₂ H ₅ ] ⁺ , 142 (18.5) [M-C ₄ H ₉ O] ⁺ .

The proposed method allows to obtain new heterocyclic compounds, namely 2,2-dimethyl-4-alkoxy-5,5-dimethyl-1,3,2-oxazasilol from hydroxyimidates by reacting the latter with dimethyldichlorosilane in the presence of triethylamine. The advantage of the proposed method is the simplicity of the technology, as well as the possibility of obtaining new heterocyclic compounds containing a silicon atom.

Claims (1)

The method of obtaining 2,2-dimethyl-4-alkoxy-5,5-dimethyl-1,3,2-oxazasilines of the formula

where R = C ₂ H ₅ , iC ₃ H ₇ , C ₄ H ₉ , consisting in the interaction of alkyl (2-methyl-2-hydroxy) propanimidate with dimethyldichlorosilane in the presence of triethylamine in anhydrous benzene medium and with a molar ratio of reactants alkyl (2-methyl-2-hydroxy) propanimidate: dimethyldichlorosilane: triethylamine (1-1.05: 1-1.01: 2.1-2.2), respectively, and a temperature of 10-15 ° C.