Carboxylic acids react with alcohols to give an ester. Acid chlorides, acid anhydrides, and also esters react with alcohols to give an ester.
To a solution of p-hydroxyquinone (53.0 mmol) and triethylamine (106 mmol) in THF (50 mL) at −30°C, acetyl chloride (53.0 mmol) was added dropwise over 20 min. After the mixture was stirred for 2 h, the reaction mixture was concentrated in vacuo and the residue was dissolved in ethyl acetate. The resulting solution was washed with water and brine, dried with magnesium sulfate and concentrated. The oily residue was purified by column chromatography to give the product in 52% yield.
Benzyl alcohol (1.0 mmol), Ac2O (2 mmol) and (C8F17SO2)2NLi (0.05 mmol) were successively added to a reaction tube. The resulting solution was stirred under 30°C until TLC showed the reaction was completed. Dichloromethane (DCM, 10 mL) was added and the precipitate of (C8F17SO2)2NLi was separated through centrifugation to recover the catalyst (49 mg). The layer of DCM solution was concentrated to give a crude product, which was purified by flash column chromatography on silica gel (pet ether/ethyl acetate=8/1) to provide the desired product in 98% yield.
Methyl benzoate (25 mmol) and tert-butyl acetate (50 mmol) were combined in a 50 mL Schlenk flask. To this mixture of liquids was added a solution of potassium tert-butoxide in THF (1 mol%, 0.25 mmol) via syringe. The reaction vessel was stirred under dynamic aspirator vacuum at 45°C for 10 min to remove methyl acetate. An additional 1 mol% of catalyst was added every 5 min until the total catalyst concentration reached 5 mol%. Analysis of the reaction mixture by GC indicate that the reaction had proceeded to >99% conversion. The catalyst was removed by passing the reaction mixture through a plug of silica gel and eluting with diethyl ether. The eluent was then evaporated in vacuo to yield 4.4 g (98%) of a colorless liquid.
The CYP2B enzymes are expressed in both lung and liver tissues in a number of animals including mouse (CYP2b10), rat (CYP2B1 and 2B2), rabbit (CYP2B4), dog (CYP2B11), and human (CYP2B6). In rabbits, the 2B4 enzyme along with the 4B1 enzyme comprises a great majority of the total pulmonary P450 enzymes, and both catalyze the bioactivation of 4-ipomeanol. In the mouse, CYP2b10 is highly expressed in Clara cells and alveolar epithelial cells, but is detectable in the liver only after phenobarbital induction. The two rat isoforms are differentially expressed in tissues: CYP2B1 is the predominant form in the lung and is expressed at low levels in the liver, while CYP2B2 is the most prevalent form in the liver (Srivastava et al. 1989). The human isoform, CYP2B6, is detected in both the lungs and the livers of most individuals.
