Methanol → 2,4,6-Trimethylphenol

##STR17## 150 mmoles of (4) in 150 ml of ether are added dropwise, at boiling temperature, to 160 mmoles of Mg in 150 ml of ether and the mixture is boiled under reflux for 1 hour. 458 mmoles of HCON(CH3)2 in 50 ml of ether are then added dropwise at -40° C. in the course of 1.5 hours and the mixture is stirred for 2 hours (temperature rises to -20° C.); distillation in vacuo gives a 75% yield of (6). ##STR18## 452 mmoles of 1-bromovinyltrimethylsilane [1*] in 100 ml of tetrahydrofuran are added dropwise to 452 mmoles of Mg in 200 ml of THP at a temperature below 50° C. and the mixture is stirred for 30 minutes. 273 mmoles of (6) in 100 ml of ether are then added at a temperature between 5° and 10° C. and the mixture is stirred for 12 hours to give (8) (yield of crude material 97%; analytical sample purified by preparative column chromatography (4:1 mixture of benzene and ethyl acetate)). ##STR19## 100 ml of Jones reagent solution [2*] are added dropwise at a temperature below 10° C. to 268 mmoles of (8) in 1 l of ether and the mixture is stirred for 15 hours at room temperature, to give (11; R=CH3) (yield 80% after distillation in vacuo). ##STR20## 205 mmoles of methylmalonic acid dimethyl ester in 20 ml of methanol are added dropwise to a solution of 217.5 mmoles of NaOCH3 in 125 ml of methanol. After stirring for 10 minutes at 50° C., 200 mmoles of (7; R=CH3) in 25 ml of hexamethylphosphoric acid triamide and 20 ml of methanol are added. The mixture is concentrated nearly to dryness (bath temperature 100°-110° C.) in the course of 1.5 hours. After partitioning the reaction material for 8 hours between 250 ml of ether and 250 ml of 10 percent strength aqueous H2SO4, (10; R=CH3) is obtained in 67% yield (after distillation in vacuo; spinning band column). ##STR21## 72.4 mmoles of (10; R=CH3) in 50 ml of methanol are added to 260 mmoles of NaOH in 250 ml of water, the mixture is kept at room temperature for 12 hours and then boiled under reflux for 10 hours. It is neutralized with concentrated hydrochloric acid (to bromothymol blue) and treated with NaH2PO4.2H2O for 2 hours. After 4 hours, the mixture is extracted with pentane and distillation of the extract in a bulb tube gives a 76% yield of (12c) and (12t) (5:95, according to gas chromatography). ##STR22## 8 ml of 0.1 N NaOC(CH3)3 in HOC(CH3)3 were added dropwise in the course of 1 hour, while stirring and at room temperature, to 20.0 mmoles of (11) and 30.2 mmoles of (12c+t) in 200 ml of ether. After 12 hours the mixture was poured into 200 ml of 10 percent strength aqueous H2SO4 and 50 ml of methanol and the resulting mixture was stirred for 48 hours. After bulb tube distillation in vacuo, preparative high-pressure liquid chromatography. (10:2 petroleum ether/ethyl acetate; 2 Waters silica cartridges. 0.15 l/minute; recycled once) and bulb tube distillation. 12.9 mmoles of (9) were isolated [yield 64.5% relative to (11)] ##STR23## 1.72 mmoles of (9), 14.7 mmoles of mesitol and 12.5 mmoles of pyridine in 450 ml of methylcyclohexane are irradiated for 12 hours at 98° C. in a Rayonet reactor (3,500 A lamp set; wavelength range <340 nm removed by filter), while passing nitrogen through the mixture. The dried crude product from irradiation is taken up in 300 ml of benzene and boiled under reflux for 20 minutes after adding 16.7 mmoles of oxalic acid. This gives (2) [yield 54%, relative to (9)] after preparative high pressure liquid chromatography (10:2 petroleum ether/ethyl acetate; 2 Waters silica cartridges, 0.1 l/minute; recycled twice).

1. distillationAfter bulb tube distillation in vacuo, preparative high-pressure liquid chromatography
2. distillation(10:2 petroleum ether/ethyl acetate; 2 Waters silica cartridges. 0.15 l/minute; recycled once) and bulb tube distillation

ORD record

ord-c7d5205146bd4506877470de4d3d1891

Source dataset

uspto-grants-1982_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04357278