Entymatic transfer of the caffeic acid to the glucosyl moiety of caffeic sugar esters

泡桐叶咖啡碱辅酶a连接酶和咖啡碱转移酶的制备。本阶段的研究仍在进行中，但作为本研究的另一个方面，获得了以下结果；以葡萄糖为原料，经21步（主要13步）合成了2-氧-2-（3,4-二羟基苯基）-乙基3- o- α- l-鼠李糖吡喃基-6- o-咖啡基-β- d -葡萄糖吡喃苷（2-氧-2- 2-二羟基苯基），总收率为7.4%。以1,2,5 -6-二-二异丙基-3- o -（2,3,4-三- o -乙酰-α- l-鼠李糖吡喃基）- d -葡萄糖为原料，经5步反应制得1,2 - o -乙酰-3- o -（2,3,4-三- o -乙酰- l-鼠李糖吡喃基）- 6- o -乙酰-d -葡萄糖吡喃糖(3)，产率为47%。以原儿茶酸为原料，经2步反应制得3,4-二o -烯丙基咖啡酸，收率达67%。以化合物3和2 ‘ ’为原料，在DCC、DMAP和DMAP- hcl存在下，合成了1,2- o -乙酰基-3- o -（2,3,4-三- o -乙酰基-α- l-鼠李糖基）- 4- o -（3,4- o -烯丙基咖啡基）-6- o -乙酰基- d -葡萄糖吡喃糖(4)，产率达98%。由化合物4和1-（3,4-二烯丙氧基苯基）-2-羟基-1-乙基（2 ',4'-二烯丙氧基苯基）经3步反应制得2-氧-2- 2- 2-o -乙酰-3- o-（2,3,4-三-o -乙酰-α- l-鼠李糖吡喃基）-4- o- （3,4- o-二烯丙基咖啡基）-6- o-乙酰-d -葡萄糖吡喃苷，收率为53%。以2-氯乙酰儿茶酚为原料，经3步反应制得化合物2”，收率为44%。对化合物5进行去保护，产率为76%，得到2-氧异乳糖苷。乙酰基的脱保护导致化合物5中咖啡因基向葡萄糖部分的C-6-OH迁移。

The preparation of caffeoyl : CoA ligase and caffeoyltransferase from the leaves of Paulownia tomentosa Steud. is still in progress in this stage of research, but as another aspect of this study, the following results were obtained ; 2-oxoisoacteoside (2-oxo-2-(3,4-dihydroxyphenyl)-ethyl 3-O-α-L-rhamnopyranosyl-6-O- caffeoyl-β-D-glucopyranoside) was chemically synthesized from glucose in the 21 reaction steps (main 13 steps) with total yield of 7.4 %. l,2-O-acetyl-3-O-(2,3,4-tri-O-acetyl-α-L-rhamnopyranosyl) -6-O-acetyl-D-glucopyranose (3) was prepared from 1,2 : 5,6-di-O-isopropylidene-3-O-(2,3,4-tri-O-acetyl-L-rhamnopyranosyl)-D- glucofuranose in the 5 reaction steps with yield of 47 %. 3,4-di-O-allylcaffeic acid(2") was prepared from protocatechuic acid in the 2 reaction steps with yield of 67 %. 1,2-O-acetyl-3-O-(2,3,4-tri-O-acetyl-α-L-rhamnosyl) -4-O-(3,4-O-allyl caffeoyl)-6-O-acetyl-D-glucopyranose (4) was prepared from compounds 3 and 2" with yield of 98 % in the presence of DCC, DMAP, and DMAP-HCl. 2-oxo-2-(3',4'-diallyloxyphenyl)-ethyl 2-O-acetyl-3-O-(2,3,4-tri-O-acetyl-α-L-rhamnopyranosyl)-4-O-(3,4-O-diallyl caffeoyl)-6-O-acetyl-D-glucopyranoside was prepared from compound 4 and 1-(3,4-diallyloxyphenyl)-2-hydroxy-1-ethanone (2"') in the 3 reaction steps with yield of 53 %. Compound 2" was prepared from 2-chloroacetyl catechol in the 3 reaction steps with yield of 44 %. Compound 5 was deprotected with yield of 76 %, giving 2-oxoisoacteoside. Deprotection of acetyl group resulted in migration of caffeoyl group to C-6-OH of glucose moiety in compound 5.