从手性氨基酸或酯经过重氮化反应得到重氮盐，该盐经水解后可以得到手性-羟基酸。

从手性氨基酸合成手性羟基酸示例1

To a 2 L round bottom three necked flask, 1,4 dioxane (625 mL) wasadded followed by O- benzyl-L-tyrosine (50 g, 0.184 mol). To this suspensiondilute aqueous sulfuric acid solution (54 g, 0.553 mol, in 175 mL water) wasadded at ca 26-28 .deg.C. It was cooled to 0 .deg.C-2 .deg.C in an ice saltBATH.. At 0 .deg.C, aqueous sodium nitrite solution (63.6 g, 0.922 mol) wasadded dropwise. After the addition, it was stirred for an extended period oftime (-UPTO 24 hours) below 30 .deg.C. It was diluted with water and extractedwith ethyl acetate. Extracts were combined and washed with water. Organic layerwas collected and dried over anhydrous sodium sulfate. It was filtered andfiltrate was concentrated below 45 .deg.C to dryness under reduced pressure toobtain crude semi-solid product (58.9 g). The crude product was purified bystirring in a mixture of diisopropyl ether ethyl acetate and filtered andwashed with diisopropyl ether. The product obtained was dried in an oven at 55.deg.C-60 .deg.C. The product weighs about 25.7 g (51 percent yield). The IHPLCassay was 92.3 percent and enatiomeric excess was 100 percent; Example 8; S (-)2-hydroxy-3- (4-benzyloxyphenyl) propanoic acid; To a 20 L round bottom threenecked flask, 1,4 dioxane (6.25 L) was added followed by 0- benzyl-L-tyrosine(500G, 1.84 mol). To this suspension dilute aqueous sulfuric acid solution (540G, 5. 53 mol, in 2.5 L water) was added at RT. It was cooled to 0 .deg.C-2.deg.C in an ice salt bath. At 0 .deg.C, aqueous sodium nitrite solution (636 g, 9.22 mol) was added. After the addition, it was stirred for extended period of time (-UPTO 24 hours) below 30 .deg.C. It was diluted with water and extracted with ethyl acetate. Extracts were combined and washed with water. Organic layer was collected and dried over anhydrous sodium sulfate. It was filtered and filtrate was concentrated below 45 .deg.C to dryness under reduced pressure to obtain crude semi-solid product (820 g). The crude product was purified by stirring in a mixture of diisopropyl ether & ethyl acetate. It was filtered and washed with diisopropyl ether. The dark yellowish product obtained was dried in an oven at 55 .deg.C-60 .deg.C. The product weighs about 235 g (47 percent yield). The HPLC assay was 98.4 percent and enatiomeric excess was 98 percent 。

从手性氨基酸合成手性羟基酸示例2

A solution of sodium nitrite (51.8 g, 720 mmol) in 200 ML of waterwas added dropwise over 6 hours to a stirred solution of L-phenylalanine (33.04g, 200 mmol) in 500 ML of 10percent sulfuric acid at 50.deg. C. After theaddition was complete, the reaction mixture was stirred for 3 hours at 50.deg.C, then at room temperature overnight.. The reaction mixture was extracted withethyl acetate (3*200 ML, 2*100 ML), then the combined organic extract waswashed with water and brine, dried over sodium sulfate and evaporated to yield28.98 g of a yellow solid. Recrystallization from benzene afforded 22.15 g ofthe title A compound as white needles, m.p. 120.deg.-124.deg. C.