CS271984B1 - 2,2,6,6-Tetramethyl-4-piperidylidene / -2-propanol and its method of preparation - Google Patents

Abstract

The solution concerns /2,2,6,6-tetramethyl--4-piperidylidene/-2-propanol and the method of its preparation by reduction of 2,2,6,6-tetramethyl--4-piperidylideneacetone during 1 to 12 n, in an organic solvent environment, at a temperature of °C to 120 °C. Complex hydrides or alkali metals are suitable as reducing agents. 2,2,6,6-Tetramethyl-4-piperidylidene/- -2-propanol can be used as an intermediate product for the production of highly effective light stabilizers of polymers and biologically effective, including pharmaceuticals.

Description

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

OH

(I) and the method of its preparation. [2,2,6,6-Tetramethyl-4-piperidylidene] -2-propanol 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-piperidinol is known from the literature (DE 2754113, CS 236 437) and from industrial practice as a major intermediate for the production of a wide range of esters, diesters and polyesters, which represent an important group of light stabilizers for polymers of the type sterically shielded amines. It is prepared by reduction of 2,2,6,6-tetramethyl-4-piperidinone (triacetaminamine) with complex hydrides or by its catalytic hydrogenation.

A new tetramethylpiperidine derivative, (2,2,6,6-tetramethyl-4-piperidylidene) -2-propanol of formula I, and a process for its preparation by treating the reducing agent with 2,2,6,6-tetramethylpiperidylideneacetone for 1 to 12 hours have now been identified. , in an organic solvent medium, at a temperature of ⁰ to 120 ° C. In case a complex hydride is used as a reducing agent, e.g. LiAlH 4 or NaAlH 2 /OCH 2 CH 2 OCH 3/2, the reaction is carried out at a temperature of ⁰ to 100 ° C. In case an alkali metal is used for the reduction, e.g. sodium or potassium metal, the reaction is carried out for 1 to 10 hours, in an environment of up to C4 alcohol, at a temperature of 20 ° C to 120 ° C.

The [2,2,6,6-tetramethyl-4-piperidylidene] -2-propanol of the formula I according to the invention can be used as an intermediate for the production of light stabilizers suitable for thermoplastic substrates such as polyolefins, polyesters, polyethers, polyurethanes, polystyrenes and optionally others. . 3e is also a suitable 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

To suspensions of 14.0 g (0.04 mol) of LiAlH. 19.5 g (0.1 mol) of 2,2,6,6-tetramethyl-4-piperidylideneacetone in 700 ml of anhydrous diethyl ether were added dropwise with stirring under stirring, and the reaction mixture was stirred for 1 h at 5 ° C. ° C and then for 7 h at reflux of diethyl ether, then the reaction mixture was cooled to 0 ° C, carefully hydrolysed with water, the resulting precipitate was filtered off and washed with diethyl ether and the organic layer of the filtrate was separated from the aqueous layer and combined with diethyl ether solution. precipitates. After drying the diethyl ether solution over anhydrous sodium sulfate, the diethyl ether was evaporated, and the solid crude product was recrystallized from n-hexane to give (2,2,6,6-tetramethyl-4-piperidylidene) -2-propanol in high yield as a white crystalline solid. mp 58.5 ⁰ to 60 ° C.

CS 271984 Bl

Elemental analysis for ^C ₁₂ ^H 23 ^NO: Calculated: 73.04% C, 11.75% H, 7.10% N

Found: 73.11% C, 11.67% H, 7.06% N ¹ H-NMR spectrum in COCl ₃ :

cT / ppm / group . 5.60 = CH - 1 H d OH 3.86 - CH - CH „1 H m Γ ³ 2.07 - CH - CH ₃ 3 H d 1.78 - CH ₂ - ring 2 H s 1.27 - 0.95 - CH ₂ - ring - OH 4 H m 1.13 CH ₃ 6 H s 1.10 ^{C —} 3 6 H s

IR spectrum, solution in CCl _4:.

p (OH) free ^{3630 cm-1} '/ )H / binding. ^{3585 Cm} '/ ^NH / ^{3330 cm} ' p / C = C / “ ^{1680 cm 1} 'Γί _{ρμ /} - 1385, 1370 / d / cm“ ¹

Example 2

To a solution of 19.5% (0.1 mol) of 2,2,6,6-tetramethyl-4-piperidylideneacetone in 300 ml of n-butanol at room temperature was added small portions of 34.5 g (1.5 mol) of metal sodium, the reaction mixture spontaneously heated to reflux temperature and refluxed at 120 ° C for 4 h. Then, the complex was hydrolyzed at room temperature, and the aqueous layer was separated and extracted with n-hexane. A solution of the product in n-butanol was combined with the n-hexane solution, the solvents were distilled off and the crude product obtained was distilled under reduced pressure to collect a fraction boiling at 68 ° to 70 ° C at 300 Pa, from which / 2.2 , 6,6-tetramethyl-4-piperidinylidene / 2-propanol as white crystals of melting point 58 ⁰ to 60 ° C.

Elemental analysis for C ₁₂ H ₂₃ NO:

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

Found

73.12% C, 11.65% H, 7.05% N ¹ H-NMR and IR spectrum the same as in Example 1.

CS 271984 Bl

Example 3

To a mixture of 15.2 g (0.4 mol) of NaBH ₄ in 150 g of diglyme, 19.5 g (0.1 mol) of 2,2,6,6-tetramethyl-4-piperidylideneacetone were added dropwise over 1 hour at room temperature. The reaction mixture was then heated at 100 ° C for 1.5 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, and the resulting complex was hydrolyzed with 5% NaHCO ₃ solution. The product was extracted from the mixture with n-hexane. After drying over anhydrous Na ₂ SO ₄ , n ** hexane was distilled off and the crude product was distilled under reduced pressure to collect a fraction boiling at 74-76 ° C at 500 Pa, from which [2,2,6,6-tetramethyl] was obtained. -4-piperidylidene / -2-propanol as a white crystalline solid, m.p.

58.5 - 60 ° C.

Elemental analysis for c ₁₂ H ₂₃ NO:

Calculated: 73.04% C 11.75% H 7.10% N

Found: 73.10% C 11.68% H 7.07% N ¹ H - NMR and IR spectrum the same as in Example 1.

Claims (4)

Example 3 To a mixture of 15.2 g / 0.4 mol / NaBH 4 in 150 g diglyme was dropped 19.5 g / 0.1 mol / 2.2.6.6 for 1 hour at room temperature. Thereafter, the reaction mixture was heated at 100 ° C for 1.5 hours. After completion of the reaction, the reaction mixture was cooled to room temperature and the resulting complex was hydrolysed with 5% NaHCO 3 solution. The product was extracted with n-hexane from the mixture. After drying with anhydrous Na 2 SO 4, n-hexane was distilled off and the crude product was distilled under reduced pressure, collecting a fraction having a boiling point of 74-76 ° C at 500 Pa from which 2,2,6,6-tetramethyl-4 was obtained. -piperidylidene / 2-propanol as a white crystalline solid, mp 58.5-60 ° C. Elemental Analysis for C 12 H 23 NO: Calcd. Found 73.04% C73.10% C 11.75% H 11.68% H 7.10% N 7.07% N 1 H-NMR and IR Spectrum Same as Example 1. 1. / 2,2,6,6-Tetramethyl-4-piperidylidene / -2-propanol of formula I OH I HC - CH - CH3 (AND) 2. A process for the preparation of 2,2,6,6-tetramethyl-4-piperidylidene / 2-propanol according to claim 1, characterized in that the 2,2,6,6-tetramethyl-4-piperidylideneacetone is with a reducing agent for 1 to 12 h, in an organic solvent, at a temperature of up to 120 ° C. 3. A process as claimed in claim 2, wherein the reducing agent is complex hydride and the reaction is carried out at a temperature of 0 to 100 ° C. 4. Process according to claim 2, characterized in that alkaline is used as the reducing agent and the reaction is carried out for 1 to 10 hours, in a medium of 2 to 4 alcohol, priteplote 20 0 to 120 ° C.