CS271983B1 - (2,2,6,6-tetramethyl-4-piperidyl)-2-propanon and method of its preparation - Google Patents

Abstract

The solution relates to / 2,2,6,6 ^ tetramethyl- And 4-piperidyl / 2-propanone by catalytic hydrogenation 2,2,6,6-tetramety1-4-piperidylidénacetónu in an atmosphere of hydrogen, in an organic environment solvents, at 20 to 120 ° C, at atmospheric! pressure or pressure to 5 MPa, in the presence of a hydrogenation catalyst, for 1 to 72 h or reduction 2,2,6,6-tetramety1-4-piperidylidénacetónu complex hydride, in pyridine medium, at 20 to 100 ° C for 3 to 8 h. Processes can be performed discontinuously or continuously. 2,2,6,6-tetramethyl- -4-piperidyl / -2-propanone can be used as an intermediate for high performance production luminous polymer stabilizers and biologically active substances, including drugs.

Description

The invention relates to (2,2,6,6-tetramethyl-4-piperidyl) -2-propanone of the formula I

CH ₂ - C - CH ₃

and the method of its preparation. [2,2,6,6-Tetramethyl-4-piperidyl] -2-propanone is an intermediate for the preparation of high-performance light stabilizers for polymers and biologically active substances, including drugs.

2,2,6,6-Tetramethyl-4-piperidone (triacetonamine) is known from the literature and from industrial practice as the main starting product for the industrial production of polymer light stabilizers as well as a whole range of polyalkylpiperidine-based drugs. 3eho synthesis is in the literature / □. Am. Chem. Soc. 79, 5444, 1957; SU 520 357; DE 3525 385; OP 1627 (1972) / described in detail.

A new tetramethylpiperidine derivative, (2,2,6,6-tetramethyl-4-piperidyl) -2-propanone of the formula I and a process for its preparation by catalytic hydrogenation of 2,2,6,6-tetramethyl-4-piperidylideneacetone under a hydrogen atmosphere have now been identified. , in an organic solvent medium, at a temperature of 20 ° to 120 ° C, at atmospheric pressure or at a pressure of up to 5 MPa, in the presence of a hydrogenation catalyst, for 1 to 72 hours, or by reduction of 2,2,6,6-tetramethyl-4- piperidylidénacetónu complex hydride in a pyridine, at a temperature of 20 ⁰ to 100 C, for 3 to 8 hours. Examples of hydrogenation catalysts which can be used are Raney-Nickel, _{Ni / Al 2} O ₃ , Ni / Cr 2 O 3, supported palladium, supported platinum, PtO ₂ or other catalysts used for this purpose. Suitable complex hydrides are, for example, LiAlH 2, Na BH 3, or NaAlH 2 / OCH 2, CH 2 OCH 2 / ". Processes can be run batchwise or continuously.

The [2,2,6,6-tetramethyl-4-piperidyl] -2-propanone of the formula I according to the invention can be used as an intermediate for the production of light stabilizers suitable for thermoplastic polymeric substrates such as polyolefins, polyesters, polyethers, polyurethanes, polystyrenes, possibly 8 more. 3e is also suitable as an intermediate for the production of biologically active substances, including drugs.

The following examples illustrate but do not limit the scope of the invention.

Example 1

19.5 g (0.1 mol) of 2,2,6,6-tetramethyl-4-piperidylideneacetone dissolved in 150 ml of diethyl ether were weighed into a hydrogenation flask with a magnetic stirrer. 1.5 g of Pd / Al "O" with a Pd content of 5% were added to the solution and the reaction mixture was stirred vigorously under a hydrogen atmosphere for 72 h at room temperature. After completion of the reaction, the catalyst was filtered off. After evaporation of diethyl ether, the crude product was distilled under reduced pressure to collect a fraction boiling at 71-2 ° C (150 Pa), from which [2,2,6,6-tetramethyl-4-piperidyl] -2-propanone was obtained as pale yellow liquid.

CS 271983 01

Elemental analysis for C ₁₂ H ₂₃ NO: 7.10% N Calculated: 73.04% C, 11.75% H, Found: 73.14% C, ¹ H-NMR spectrum in CDCl ₃ : (ppm) 2.27 11.59% H, group -ch ₂ -co- 7.03% N I 2 H M d 2.11 -co-ch ₃ 3 H with 1.17 . ^ch ₃ ax. 6 H with 1.04 ^{S CH} 3 eg. 6 H with 1.75 to 0.33 ' , -CH ₂ -, • ^ CH - circle 6 H m IR spectrum, solution in CCl2) / C = O / - 1735 cm- ¹ , 4 ^: ( ^NH ) free 3330 cm ¹ , Γ / CH óyn.as. "

430 cm ¹

1380, 1365 cm- ¹ , \) / NH /.

* 'vxaz

Example 2

19.5 g (0.1 mol) of 2,2,6,6-tetramethyl-4-piperidylacetone were weighed into a 100 ml pressure vessel of an autoclave equipped with a stirrer, a thermometer and a manometer, 45 ml of methanol and 0.6 g of Raney catalyst were added. -Nickel. After sealing, the autoclave vessel was purged with hydrogen, the reaction mixture was heated to 120 ° C and stirred at a hydrogen pressure of 5.0 MPa for 1.5 h. After completion of the reaction, the catalyst was filtered off, the solvent was distilled off at atmospheric pressure, and the crude product was distilled off under reduced pressure to obtain a fraction having a boiling point of 83-5 ° C / 400 Pa. A slightly colored clear liquid of the product [2,2,6,6-tetramethyl-4-piperidyl] -2-propanone was obtained.

Elemental analysis for ^C ₁₂ ^H 23 ^NO:

Calculated: 73.04% C

Found: 72.87% C

11.75% H

11.53% H

7.10% N

7.03% N

- NMR spectrum in CDCl 3 and IR - spectrum in CCl. were the same as in Example 1. Π ó T ·

Example 3

A 0.5 m long flow hydrogenation reactor with an internal diameter of 25 mm was charged with 100 g of Ni-Cr ₂ O ₃ catalyst containing 60% Ni. After activating the catalyst with hydrogen, a 30% solution of 2,2,6,5-tetramethyl-4-piperidylideneacetone in 2-propanol was metered into the reactor in an amount of 250 g. h ¹ , at a temperature of 70 ° C and a hydrogen pressure of 3.5 MPa. After distilling off the solvent, the crude product was distilled off under reduced pressure, and a fraction boiling at 71-2 DEG C./150 mm was collected, from which [2,2,6,6-tetramethyl-4-piperidyl] -2-propanone was obtained as slightly colored liquid.

CS 271983 Bl

Elemental analysis for C ₁₂ H ₂₃ NO:

Calculated: 73.04% C .11.75% H 7.10% N

Found: 73.11% C 11.54% H 7.06% N ¹ H-NMR and IR-spectrum as in Example 1.

Example 4

_{3.8 g (0.1 mol) of NaBH 4} were weighed into a 250 ml three-necked flask equipped with a stirrer, a thermometer and a dropping funnel, and 150 ml of pyridine were added. After dissolving NaBH 4 in pyridine, 4.9 g (0.025 mol) of 2,2,6,6-tetramethyl-4-piperidylideneacetone was added dropwise to the solution over 1 h. The reaction mixture was then stirred at 100 ° C for an additional 2 h. _{After completion of the reaction, a 5% NaHCO 3} solution was added to the reaction mixture at room temperature, and after separating the pyridine layer, the aqueous layer was further extracted with n-hexane. After drying the combined organic solutions, n-hexane was distilled off in vacuo, pyridine under slightly lower pressure and the crude product was distilled under reduced pressure to collect a fraction boiling at 69-70.5 ° C at 100 Pa, from which / 2,6,6-tetramethyl-4-piperidyl] -2-propanone as a colorless liquid.

Elemental analysis

Calculated: 73.04% C 11.75% H 7.10% N

Found: 72.87% C 11.68% H 7.06% N ¹ H - NMR and IR spectrum as in Example 1

Claims (3)

OBJECT OF THE INVENTION 1. (2,2,6,6-Tetramethyl-4-piperidyl) -2-propanone of the formula I H ₂ C - C - CH ₃ H (I) 2. A process for the preparation of [2,2,6,6-tetramethyl-4-piperidyl] -2-propanone according to item 1, characterized in that 2,2,6,6-tetramethyl-4-piperidylideneacetone is subjected to catalytic hydrogenation in a hydrogen atmosphere, in an organic solvent medium, at a temperature of 20 to 120 ° C, at atmospheric pressure or at a pressure of up to 5 MPa, in the presence of a hydrogenation catalyst, for 1 to 72 h. CS 271983 Bl 3. A process for the preparation of (2,2,6,6-tetramethyl-4-piperidyl) -2-propanone according to item 1, characterized in that 2,2,6,6-tetramethyl-4-piperidylideneacetone is treated with a complex hydride. , in the environment of pyridine, at a temperature of 20 to 100 ° C, for 3 to 8 hours.