中文名称 | 英文名称 | CAS号 | 化学式 | 分子量 |
---|---|---|---|---|
2-甲基-2,3-二羟基丁酸乙酯 | α,β-dihydroxy-isovaleric acid ethyl ester | 63962-99-2 | C7H14O4 | 162.186 |
—— | 3,3-dimethyl-oxirane-2-carboxylic acid | 4374-53-2 | C5H8O3 | 116.117 |
2-羟基-3-甲基丁酸乙酯 | ethyl 2-hydroxy-3-methylbutanoate | 2441-06-7 | C7H14O3 | 146.186 |
—— | ethyl 3-ethoxy-2-hydroxy-3-methylbutanoate | 147111-39-5 | C9H18O4 | 190.24 |
—— | (+/-)-ethyl 2-hydroxy-3,3-dimethylbutanoate | 42282-48-4 | C8H16O3 | 160.213 |
3-Acetoxy-1,4-dibenzyl-3-[1-(2-methoxyethyl)ethenyl]piperazine-2,5-dione (32) and its 2-hydroxyethyl analogue (46), which possess several of the structural features of the antibiotic bicyclomycin, have been synthesized by a route involving construction of the piperazine-2,5-dione ring at a late stage in the reaction sequence. Treatment of ethyl 3-(2-methoxyethyl)-3-methylglycidate with acetic anhydride and sulfuric acid gives ethyl 2-acetoxy-3-(2-methoxyethyl)-3-butenoate (10), which is converted to the corresponding carboxylic acid by ethanolysis, hydrolysis, and reacetylation. This, on conversion to its acid chloride and reaction with N,N′-dibenzylglycinamide, gives 2-acetoxy-N-benzyl-N-(2-benzylamino-2-oxocthyl)-3-(2methoxyethyl)-3-butenamide (21). Compound 21, on hydrolysis and oxidation, gives the corresponding 2-oxo compound, which on treatment with magnesium isopropylcyclohexylamide followed by acetylation yields 32. Demethylation of 21 with alkylthiotrimethylsilanes gives the corresponding 2-hydroxyethyl compound, whose tetrahydropyranyl ether on subjection to the above reaction sequence gives the 2-(tetrahydropyran-2-yloxy)ethyl analogue of 32. This, on hydrolysis, gives a 3: 1 mixture of compound 46 and a spiro compound formed by displacement of the acetoxyl group by the hydroxyl oxygen atom of 46.
A general method of synthesis of 3-alkyl (or aryl) 3-fluoro 2-oxo esters is described. The opening of glycidic esters with HF–pyridine (70% w/w), followed by oxidation with Jones reagent, give the corresponding derivatives of fluoropyruvic esters in good yields.