RU2283826C1 - Method for production of 3,6-dimethyl-1,8-dialkyl(phenyl)-2,6-octadiens - Google Patents

Abstract

FIELD: organic chemistry.

SUBSTANCE: alkyl(benzyl)allene of general formula (R-= =), wherein R is n-C₂H₁₁, n-C₆H₁₃,CH₂Ph is reacts with EtMgBr, Mg, Cp₂TiCl₂, methyl iodide and CuCl in argon atmosphere in tetrahydrofuran medium for 18-22 hours. Total yield of target products is 69-86 %.

EFFECT: selective method for production of 3,6-dimethyl-4,7-dialkyl(phenyl)-2,6-octadiens.

1 tbl, 1 ex

Description

The present invention relates to organic chemistry, in particular to a method for producing 3,6-dimethyl-1,8-dialkyl (phenyl) -2,6-octadiene of the general formula (I):

The proposed compounds can be used in fine organic synthesis, in the production of plasticizers, additives, polymeric materials, aromatic components, as well as in the synthesis of biologically active preparations.

A known method ([1], Takahashi T., Kotora M., Kasai K., Suzuki N. // Organometallics, 1994, 13, 4183) for producing 4,5,6,7-tetraalkyl-1,4,6,9 -decatetraenes (2) by the interaction of zirconacyclopentanes with allyl chloride in the presence of stoichiometric amounts of CuCl according to the scheme:

The known method does not allow to obtain 3,6-dimethyl-1,8-dialkyl (phenyl) -2,6-octadiene (1).

The known method ([2], Dzhemilev U.M., Ibragimov A.G., Azhgaliev M.N., Musloukhov PP // Izv. 5,6-dialkyl (aryl) -1,9-decadienes (3) by cross-coupling of 1,4-dialuminium compounds with allyl halides under the action of copper catalysts according to the scheme:

In a known manner, 3,6-dimethyl-1,8-dialkyl (phenyl) -2,6-octadiene (1) cannot be obtained.

Thus, in the literature there is no information on the selective synthesis of 3,6-dimethyl-1,8-dialkyl (phenyl) -2,6-octadiene (1).

A new method is proposed for producing 3,6-dimethyl-1,8-dialkyl (phenyl) -2,6-octadiene (1).

The essence of the method is the interaction of alkyl (benzyl) allenes of the general formula R- = · =, where R = n — C ₅ H ₁₁ , n — C ₆ H ₁₃ , CH ₂ Ph, with ethyl magnesium bromide and activated magnesium (Mg, powder), taken in the ratio R- = · =: EtMgBr: Mg = 10: (10-14) :( 5-7) mmoles, preferably 10: 12: 6 mmoles, in the presence of a catalyst titanium-dichloride (Cp ₂ TiCl ₂ ) in the amount of 0.3- 0.7 mmol, preferably 0.5 mmol, in an argon atmosphere at room temperature (~ 20 ° C) and atmospheric pressure in THF for 8-12 hours, preferably 10 hours, followed by addition to the reaction mass at a temperature e -20 ° C CuCl catalyst in an amount of 1.8-2.2 mmol, preferably 2mmol and methyl iodide in equimolar relative to the amount of EtMgBr. Subsequent stirring of the reaction mass for 10 hours at a temperature of ~ 20 ° C. Receive 3,6-dimethyl-1,8-dialkyl (phenyl) -2,6-octadiene (1) with a total yield of 69-86%. The reaction proceeds according to the scheme:

Целевой продукт 3,6-диметил-1,8-диалкил(фенил)-2,6-октадиен (1) образуется только лишь с участием алкил(бензил)алленов, EtMgBr и метилиодида.

The target product 3,6-dimethyl-1,8-dialkyl (phenyl) -2,6-octadiene (1) is formed only with the participation of alkyl (benzyl) allenes, EtMgBr and methyl iodide.

Changing the ratio of the starting reagents and catalysts in the direction of their increase relative to the starting allene does not lead to a significant increase in the yield of the target product (1). A change in the ratio of the starting reagents and the catalyst in the direction of their decrease relative to the starting allene leads to a significant decrease in the yield of the target product (1).

Reactions were carried out using THF as a solvent. In other solvents (for example, aliphatic or aromatic), the reaction does not proceed.

Significant differences of the proposed method:

1. In the proposed method, alkyl (benzyl) allens, EtMgBr and methyl iodide are used as starting compounds. In a known method, the compound (3) is obtained from 1,4-diallyuminium compounds.

The proposed method has the following advantages:

1. The method allows to obtain with high selectivity 3,6-dimethyl-1,8-dialkyl (phenyl) -2,6-octadiene (1), the synthesis of which is not described in the literature.

The method is illustrated by the following examples.

EXAMPLE 1. In a 50 ml glass reactor mounted on a magnetic stirrer in an argon atmosphere, 12 mmoles of freshly prepared EtMgBr in a THF solution, 6 mg at. Mg (powder), 10 mmol of 1,2-octadiene and 0.5 mmol of Cp ₂ TiCl ₂ , stirred for 10 hours at room temperature (~ 20 ° C), at a temperature of -20 ° C added 2 mmol of CuCl and 12 mmol of allyl chloride, stirred 10 hours at a temperature of ~ 20 ° C. At the end of the reaction, the catalysis is treated with 5% HCl, extracted with ether, dried with MgSO ₄ . After removal of solvent, the residue was distilled in vacuo, 7,10-dimethyl-6,10-hexadecadiene (1) was isolated in 79% yield.

Spectral characteristics of 7,10-dimethyl-6,10-hexadecadiene (1):

). Спектр ЯМР ¹³С (δ, м.д.): 13.89 С (1, 16); 22.49 С (2, 15); 23.34 С (17, 18); 29.72 С (4, 13); 27.05 С (5, 12); 27.70 С (8, 9); 31.57 С (3, 14); 125.52 С (6, 11); 135.03 С (7, 10). Масс-спектр, m/z: М⁺ 250.IR spectrum. ν / cm ^-1 : 3030, 2950, 2860, 1650, 1490, 1450, 1390, 1000, 910, 890, 720. ¹ Н NMR spectrum (δ, ppm): 0.65-0.89 (t, 6Н, J = 6.0 Hz, CH ₃ ); 1.11-1.35 (m, 12H, CH ₂ ); 1.61 (s, 6H, CH ₃ -C); 1.81-2.21 (m, 8H, CH ₂ -C = C); 5.0-5.36 (t, 2H, J = 6.0 Hz,

) ¹³ C NMR spectrum (δ, ppm): 13.89 C (1, 16); 22.49 C (2, 15); 23.34 C (17, 18); 29.72 C (4, 13); 27.05 C (5, 12); 27.70 C (8, 9); 31.57 C (3, 14); 125.52 C (6, 11); 135.03 C (7, 10). Mass spectrum, m / z: M ⁺ 250.

Other examples confirming the method are given in table 1.

Table 1 №№ Allens, R- = · = The molar ratio R- = · =: EtMgBr: Mg: Cp ₂ TiCl ₂ : MeI: CuCl, mmol Reaction time, hour Yield (1),% one 2 3 four 5 one. nC ₅ H ₁₁ - = · = n-amylallen 10: 12: 6: 0.5: 12: 2 twenty 79 2. - "- 10: 14: 6: 0.5: 14: 2 twenty 83 3. - "- 10: 10: 6: 0.5: 10: 2 twenty 72 four. - "- 10: 12: 7: 0.5: 12: 2 twenty 81 5. - "- 10: 12: 5: 0.5: 12: 2 twenty 73 6. - "- 10: 12: 6: 0.7: 12: 2 twenty 86 7. - "- 10: 12: 6: 0.3: 12: 2 twenty 69 8. - "- 10: 12: 6: 0.5: 12: 2 22 85 9. - "- 10: 12: 6: 0.5: 12: 2 eighteen 74 10. - "- 10: 12: 6: 0.5: 12: 1.8 twenty 76 eleven. - "- 10: 12: 6: 0.5: 12: 2.2 twenty 85 12. n-C ₆ H ₁₃ - = · = n-hexylallen 10: 12: 6: 0.5: 12: 2 twenty 78 13. PhCH ₂ - = · = benzylallen 10: 12: 6: 0.5: 12: 2 twenty 70

Reactions were carried out at room temperature (20-21 ° C) in THF.

Claims (1)

The method of obtaining 3,6-dimethyl-1,8-dialkyl (phenyl) -2,6-octadiene of the General formula (1)

characterized in that the alkyl (benzyl) allen of the general formula (R- = · =), where R = n — C ₅ H ₁₁ , n — C ₆ H ₁₃ , CH ₂ Ph, is reacted with ethyl magnesium bromide (EtMgBr) and metal magnesium in a molar ratio of R- = · =: EtMgBr: Mg, equal to 10: (10-14) :( 5-7), in the presence of a titanacenedichloride catalyst (Cp ₂ TiCl ₂ ), taken in an amount of 3-7 mol.% in relation to allene, in an argon atmosphere at room temperature and atmospheric pressure in THF as a solvent for 8-12 hours, followed by the addition of a catalyst of monochloride (CuCl) in an amount of 18-2 at -20 ° С 2 mol% with respect to allene and methyl iodide in an amount equimolar to EtMgBr and stirring the reaction mixture for 10 hours at room temperature.