2,5-dimethylbenzene-1,4-diol

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 10 mmol of 2,5-dimethylhydroquinone in 25 mL of chlorobenzene, 20 mmol of 1-bromo-5,8,11-trioxadodecane, 20 mmol of sodium hydroxide in the form of a 50% aqueous solution are reacted in the presence of a phase transfer catalyst, tetrabutylammonium bromide. The 1,4-dimethyl-2,5-bis(5,8,11-trioxadodecyloxy)benzene thus obtained is purified by chromatography. 1,4-bis(Bromomethyl-2,5-bis(5,8,11-trioxadodecyloxy)benzene is obtained by treatment with two equivalents of N-bromosuccinimide. Duplicative elimination by potassium tert-butoxide in THF gives the polymer.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 10 mmol of 2,5-dimethylhydroquinone in 25 mL of chlorobenzene, 20 mmol of 1-bromo-5,8,11-trioxadodecane, 20 mmol of sodium hydroxide in the form of a 50% aqueous solution are reacted in the presence of a phase transfer catalyst, tetrabutylammonium bromide. The 1,4-dimethyl-2,5-bis(5,8,11-trioxadodecyloxy)benzene thus obtained is purified by chromatography. 1,4-bis(Bromomethyl-2,5-bis(5,8,11-trioxadodecyloxy)benzene is obtained by treatment with two equivalents of N-bromosuccinimide. Duplicative elimination by potassium tert-butoxide in THF gives the polymer.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In a similar manner to that described in Reference Example 6, a reaction was carried out using 2,5-dimethylhydroquinone (1.38 g), t-butyl N-(5-chloro-2-nitrophenyl)-N-methylcarbamate (2.87 g), sodium hydride (55 wt. %, 0.87 g) and anhydrous N,N-dimethylformamide (20 ml) and the reaction mixture was purified to give the title compound (1.72 g). the reaction mixture was purified

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In a similar manner to that described in Reference Example 6, a reaction was carried out using 2,5-dimethylhydroquinone (1.38 g), t-butyl N-(5-chloro-2-nitrophenyl)-N-methylcarbamate (2.87 g), sodium hydride (55 wt. %, 0.87 g) and anhydrous N,N-dimethylformamide (20 ml) and the reaction mixture was purified to give the title compound (1.72 g). the reaction mixture was purified

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2,5-Dimethylbenzoquinone (5 g) in ethyl acetate was shaken with an aqueous solution of sodium hydrosulfite. The organic layer was separated, washed, dried and evaporated to yield 2,5-dimethylhydroquinone. To a solution of 2,5-dimethylhydroquinone (5 g), prepared as described above, and 3-methyl-2-buten-1-ol (3.1 g) in dioxane (20 mL) was added BF3-ether (4.5 mL) at room temperature under nitrogen. The solution was stirred at room temperature for one hour, extracted with ethyl acetate, washed with water and dried. The mixture containing starting material and alkylated product was hydrogenated in methanol (100 mL) with 5 drops of concentrated HCl in the presence of Pd/C (10%, 200 mg) at60 psi for 18 hours. Workup and chromatography (silica gel hexane-ethyl acetate 5% to 12%) gave 2 g of the desired product, 2,5-dimethyl-3-(3-methyl-butyl)-hydroquinone. extracted with ethyl acetate washed with water dried The mixture containing was hydrogenated in methanol (100 mL) with 5 drops of concentrated HCl in the presence of Pd/C (10%, 200 mg) at60 psi for 18 hours

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2,5-Dimethylbenzoquinone (5 g) in ethyl acetate was shaken with an aqueous solution of sodium hydrosulfite. The organic layer was separated, washed, dried and evaporated to yield 2,5-dimethylhydroquinone. To a solution of 2,5-dimethylhydroquinone (5 g), prepared as described above, and 3-methyl-2-buten-1-ol (3.1 g) in dioxane (20 mL) was added BF3-ether (4.5 mL) at room temperature under nitrogen. The solution was stirred at room temperature for one hour, extracted with ethyl acetate, washed with water and dried. The mixture containing starting material and alkylated product was hydrogenated in methanol (100 mL) with 5 drops of concentrated HCl in the presence of Pd/C (10%, 200 mg) at60 psi for 18 hours. Workup and chromatography (silica gel hexane-ethyl acetate 5% to 12%) gave 2 g of the desired product, 2,5-dimethyl-3-(3-methyl-butyl)-hydroquinone. The organic layer was separated washed dried evaporated

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In the second method for forming the single enantiomer chroman diol, (2S) 2-hydroxymethyl-6-hydroxy-2,5,8-trimethylchroman for use as starting material in the present tocotrienol syntheses, a suitably monoprotected 2,5-dimethylhydroquinone is reacted with the compound 3-hydroxy-3-methyl-1,4-pentadiene to produce 2-vinyl-2,5,8-trimethylchroman-6-ol:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: By following in the same manner as in Example 53, except that 100 g. (819 m. moles) of 2,5-dimethylphenol were used instead of 3,5-dimethylphenol, 1.45 g. (10.5 m. moles) of 3,6-dimethylcatechol and 1.85 g. (13.4 m. moles) of 2,5-dimethylhydroquinone were obtained. The yield of dihydric alkylphenols was 46.9 percent.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 10 mmol of 2,5-dimethylhydroquinone in 25 mL of chlorobenzene, 20 mmol of 1-bromo-5,8,11-trioxadodecane, 20 mmol of sodium hydroxide in the form of a 50% aqueous solution are reacted in the presence of a phase transfer catalyst, tetrabutylammonium bromide. The 1,4-dimethyl-2,5-bis(5,8,11-trioxadodecyloxy)benzene thus obtained is purified by chromatography. 1,4-bis(Bromomethyl-2,5-bis(5,8,11-trioxadodecyloxy)benzene is obtained by treatment with two equivalents of N-bromosuccinimide. Duplicative elimination by potassium tert-butoxide in THF gives the polymer.