酯化和酰胺化

HOOCCOOHOHOH2TsOH, toluene2CH2Ph2CH2PhA 300-mL, one-necked, round-bottomed flask was equipped with a magnetic stirrer, Dean-Stark trap, and a reflux condenser. The flask was charged with 3.0 g (20 mmol) of L-(+)-tartaric acid, 6.5 g (60 mmol) of benzyl alcohol, 47.5 mg (0.25 mmol) of p-toluenesulfonic acid monohydrate and 40 mL of toluene. The mixture was heated under reflux in an oil bath (about 130℃) for 13 h r. During this period the theoretical amount of water (0.62 mL) was collected. The mixture was allowed to cool to ambient temperature, diluted with ether, and poured into 50 mL of aqueous, saturated sodium bicarbonate. The organic phase was separated and the aqueous phase was extracted twice with 20 mL of ether. The combined organic phases were dried over sodium sulfate. The solvent was removed with a rotary evaporator, and the resulting crude product was triturated with hexane-ether (20:1, 210 mL) to give white crystals of (−)-dibenzyl tartrate. The precipitate was collected by filtration and washed with hexane-ether (20:1). The filtrate was further concentrated to give a second crop. The total yield was 6.2 g (94%), mp 49–50℃[5]2.5 酰氯和醇、酚的酯化反应示例：酰氯是强酰化剂和醇、酚作用生成酯的反应很迅速，此方法适用于由空间障碍的酯化。

经常是在吡啶或其它叔胺参与下反应。

F3C223In an oven-dried, 500-mL, two-necked, round-bottomed flask equipped with a magnetic stir bar and a rubber septum was placed 1,3,5-tri-O-benzoyl-α-D-ribofuranose (5.0 g, 10.8 mmol) and 2,6-lutidine (1.4 g, 13.0 mmol) in 200 mL of dry dichloromethane under an argon atmosphere. The reaction mixture was cooled to 0℃and 3-(trifluoromethyl)benzoyl chloride (3.3 g, 16.2 mmol) was added dropwise to the stirred solution over 30 min. After the addition, the reaction mixture was warmed to room temperature and stirred overnight. The reaction was quenched with 80 mL of aqueous saturated sodium bicarbonate, the phases were separated and the aqueous phase wasextracted with dichloromethane (200 mL × 2). The combined organic extracts were washed with brine (100 mL × 2) and dried over anhydrous magnesium sulfate. After filtration, the solvent was removed under reduced pressure to give yellow oil. Purification by flash column chromatography (140 g of silica gel) and eluting with 25% ethyl acetate in hexanes gives a white solid that can be recrystallized from EtOAc/hexane to yield 1,3,5-O-tribenzoyl-2-O[(3- trifluoromethyl)benzoyl]- -α-D-ribofuranose (5.62 g, 82%) as white crystals[14].OClNO2ClCl OHClCl OONO2pyridineA mixture of 28.5 g of 4-nitrobenzoyl chloride, 30.0 g of 3,5-dichlorophenol and 300 mL of pyridine was heated under reflux for 3 h.After completion of the reaction, the pyridine was distilled off under reduced pressure, the remaining reaction product was dissolved in ethyl acetate, and the solution was washed with water and then with a saturated aqueous solution of sodium chloride and concentrated under reduced pressure to give crude crystals, which was recrystallized from ethyl acetate to give 3,5-dichlorophenyl-4-nitrobenzoate (44.2 g) as needles [15].酯和另一种过量的醇在少量的碱或酸催化下共热，发生烷氧基转移，生成另一种酯。

O NOOH23ONOA mixture of Ethyl 2-cyano-3,3-diphenylacrylate (83.1 g，0.3 mol), cyclopentanol (100 mL) and Na2CO3 (6 g) were heated at 145℃with disstillative removal of theethanol formed, assisted by a stream of nitrogen. After about 3 h, the reaction mixture was filtered hot in order to remove the Na 2CO 3. After the filtrate had been cooled, the precipitate which had formed was filtered off, washed with petroleum ether and dried to give cyclopentyl 2-cyano-3, 3-diphenylacrylate (78.1 g, 82%) as a colorless solid [17].OClOOON NO 2OOON 2p-TsOHThe mixture of 500 mg of 3-acetyloxy-7-[(5-nitro-2-pyridinyl)oxy]-1H-indene, 5 ml of benzoyl chloride and 15 mg of p-toluenesulfonic acid was stirred at 100℃. After stirring for 1.5 h, ethyl acetate was added to the reaction solution and the solution was washed in turn with a saturated sodium hydrogencarbonate solution and a saturated sodium chloride solution. The solution extracted with ethyl acetate was dried over anhydrous magnesium sulfate and the solvent was distilled off. The resulting residue was purified by silica gel column chromatography (eluent: hexane/ethyl acetate=10:1) to obtain 130 mg of 3-benzoyloxy-7- [(5-nitro-2-pyridinyl) oxy]-1H-indene as a white powder [18].EtO 2CCO 2H H HEtO 2CCO 2t-Bu H HC H N=C=C H NNNA 500-mL, one-necked flask equipped with a calcium chloride drying tube was charged with 28.83 g (0.20 mol) of monoethyl fumarate, 200 mL of dry dichloromethane, 44.47 g (0.60 mol) of tert-butyl alcohol, and 2.00 g (0.16 mol) of 4-dimethylaminopyridine. The solution was stirred and cooled in an ice bath to 0°C while 45.59 g (0.22 mol) of dicyclohexylcarbodiimide was added over a 5-min period. After a further 5 min at 0°C the ice bath was removed and the dark-brown reaction mixture was stirred for 3 h at room temperature. The dicyclohexylurea that has precipitated was removed by filtrationthrough a fritted Büchner funnel(多孔布氏漏斗) (G3), and the filtrate was washed with two 50-mL portions of 0.5 N hydrochloric acid [无化] 盐酸and two 50 mL portions of saturated sodium bicarbonate solution(部分饱和碳酸氢钠溶液). During this procedure some additional dicyclohexylurea was precipitated(adj.沉淀的),which was removed byfiltration of both layers to facilitate their separation. The organic solution was dried over anhydrous sodium sulfate([无化]无水硫酸钠)and concentrated with a rotaryevaporator. The concentrate was distilled under reduced pressure, affording after a small forerun, 30.5–32.5 (76–81%) of tert-butyl ethyl fumarate, bp 105–107°C (12mm)[25].[25]: Organic Syntheses, Coll. Vol. 7, p.93 (1990); Vol. 63, p.183 (1985).例如将α-羟基乙酸及苄胺于90℃共热， 并蒸出生成的水及过量的苄胺，则生成α-羟基乙酰基苄胺i 。