(3aS,6aR)-1,3-二苄基-四氢-4H-呋喃并[3,4-d]咪唑-2,4(1H)-二酮的立体选择性合成

Synthesis of(3aS,6aR)-1,3-dibenzyl-tetrahydro-4H-furoimidazole-2,4(1H)-dione by stereoselective reduction

以顺-1,3-二苄基-5-[(1S,2S)-(+)-苏式-1-羟甲基-2-(对硝基苯基)-2-羟乙基]-四氢-4H-吡咯并[3,4-d]咪唑-2,4,6-三酮为原料,经单乙酰化、NaBH4还原和酸水解得到标题化合物,与直接还原或是先经双乙酰化再还原的工艺相比,单乙酰化后再还原的选择性高达97.25%。并对单乙酰化物和双乙酰化物结构做了X单晶衍射测定,单乙酰化物的原子空间排布更利于选择性还原。

（3aS,6aR） -1,3-Dibenzyl-tetrahydro-4H-furo [ 3,4- d] imidazole-2,4 （1 H）-dione, as the key intermediate of d-bi- otin, can be synthesized from cis-1,3-dibenzy]-5- [ （ 1S, 2S） - （ ＋ ）-threo-l-hydroxymethyl-2-（ p-nitrophenyl ）-2-hydroxy- ethyl -tetrahydro-4H-pyrro [ 3,4-d ] imidazole-2,4, 6-trione via single-acylation, reduction by NaBH4, and hydrolyzation, in which more higher reduction selectivity of 97.25% can be obtained compared with the technics of straight reduction or the double-acylation. The structures of the single-acylate and double-acylate were confirmed by X-ray diffraction,which indicates the atom arrangement of the single-acylate is more suitable for stereoselective reduction.