OBJECTIVE To stereospecifically synthesize disaccharide galactopyranosyl(α1→2)glucopyranoside with protecting groups which are easily and selectively deprotected.METHODS With D-glucose as a raw material,a donor methyl 3,4,6-tri-O-benzoyl-β-D-glucopyranoside was synthesized through acetylation,bromination,methylation,deacetylation,benzylidenation,selective benzoylation,chloroacetylation,and dechloroacetylation;the glucopyranosyl acceptor and a donor isopropyl 3-O-allyl-2-O-benzoyl-4,6-O-benzylidene-β-D-1-thiogalactopyranoside were reacted at catalysis to achieve an α-coupled product.RESULTS At the catalysis of TMSOTf/NIS,galactopyranosyl donor and glucopyranosyl acceptor were coupled to afford stereospecifically a full protected disaccharide galactopyranosyl(α1→2)glucopyranoside fragment,methyl 3-O-allyl-2-O-benzoyl-4,6-O-benzylidene-α-D-galactopyranosyl(1→2)-3,4,6-tri-O-benzoyl-β-D-glucopyranoside.All products were characterized with NMR and MS etc.CONCLUSION A full protected 1,2-cis disaccharide fragment was stereospecifically obtained through coupling reaction due to concerted effect of the special configurations of the galactopyranosyl donor and the glucopyranosyl acceptor.

OBJECTIVE To achieve a protected disaccharide galactopyranosyl(α1→2) glucopyranoside fragment with a 1,2-cis galactosyl linkage and protected groups easily selectively deprotected.METHODS Through multiple protecting and coupling protocol,methyl 3-O-allyl-2-O-benzoyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3,4,6-tri-O-benzoyl-α-D-glucopyranoside(11) was synthesized with D-galactose and D-glucose as raw materials.RESULTS Methyl 3,4,6-tri-O-benzoyl-α-D-glucopyranoside was achieved via selective acetylation,benzoylation,debenzylidenation,benzoylation and selective deacetylation of methyl 4,6-O-benzylidene-α-D-glucopyranoside from D-glucose.A donor isopropyl 3-O-allyl-2-O-benzoyl-4,6-O-benzylidene-1-thio-β-D-galactopyranoside from D-galactose and an acceptor methyl 3,4,6-tri-O-benzoyl-α-D-glucopyranoside were coupled to obtain methyl 3-O-allyl-2-O-benzoyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3,4,6-tri-O-benzoyl-α-D-glucopyranoside and methyl 3-O-allyl-2-O-benzoyl-4,6-O-benzylidene-β-D-galactopyranosyl-(1→2)-3,4,6-tri-O-benzoyl-α-D-glucopyranoside,and the stereoselective ratio of α-galactosyl linkage to β-galactosyl linkage was 3∶1.All products were characterized with NMR,MS etc.CONCLUSION The protected disaccharide Gal(α1→2) Glc fragment 3-O-allyl-2-O-benzoyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3,4,6-tri-O-benzoyl-α-D-glucopyranoside was stereoselectively synthesized for the first time.

In order to improve the thermal stability of L-menthol,several coupling methods and their related protection and deprotection reactions for L-menthyl β-Dglucoside synthesizing were investigated,the coupling reaction conditions of β-D-glucose pentaacetate with L-menthol were discussed,and the melting point,optical rotation,NMR,MS and TG of the synthesized product were analyzed.The results showed that: 1) it is feasible to synthesize L-menthyl β-D-glucoside from glucose and L-menthol through three-step reaction of acetylation,coupling, and deprotection;2) the synthesized product is the target product;3) the optimized condition of coupling reaction was solvent CH2Cl2,n(β-D-glucose pentaacetate):n(L-menthol):n(BF3·Et2O)=1∶3∶5,reaction temperature 25 ℃,and reaction time 10 hours,at which the yield reached 40%;4) the synthesized product,L-menthyl β-D-glucoside,featured high thermal stability.

The novel chemical synthesis of a protected disaccharide Gal(α1→2)Glc was reported for the first time.Methyl-4,6-O-benzylidene-α-D-glucopyranoside was converted into methyl-3-O-benzoyl-4,6-O-benzylidene-α-D-glucopyranoside by selective benzoylation.Isopropyl-3-O-allyl-2-O-benzoyl-4,6-O-benzylidene-1-thio-β-D-galactopyranoside and methyl-3-O-benzoyl-4,6-O-benzylidene-α-D-glucopyranoside were coupled into methyl-3-O-allyl-2-O-benzoyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3-O-benzoyl-4,6-O-benzylidene-α-D-glucopyranoside,a protected disaccharide Gal(α1→2)Glc fragment.All compounds were characterized by NMR,MS etc.

建立了一种新的保护的二糖半乳吡喃糖基（α1→2）葡萄吡喃糖苷的合成方法。甲基-4,6-O-苄叉基-β-D-葡萄吡喃糖苷（1）经区域选择性地苯甲酰化,得到受体甲基-3-O-苯甲酰基-4,6-O-苄叉基-β-D-葡萄吡喃糖苷（2）。该受体与供体异丙基-2-O-苯甲酰基-3-O-烯丙基-4,6-O-苄叉基-β-D-1-硫代半乳吡喃糖苷（4）偶联,获得了一种保护的二糖Galp（α1→2）Glcp片段甲基-2-O-苯甲酰基-3-O-烯丙基-4,6-O-苄叉基-α-D-半乳吡喃糖基-（1→2）-3-O-苯甲酰基-4,6-O-苄叉基-β-D-葡萄吡喃糖苷（5）。所有的产品通过NMR、MS等方法进行了结构表征。

A novel 1,2-cis stereoselective synthesis of protected α-D-Gal-(1→2)-D-Glc fragments was developed. Methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3-O-benzoyl-4,6-O-benzylidene-α-D-glucopyranoside (13), methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3,4,6-tri-O-benzoyl-α-D-glucopyranoside (15), methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3-O-benzoyl-4,6-O-benzylidene-β-D-glucopyranoside (17), and methyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-α-D-galactopyranosyl-(1→2)-3,4,6-tri-O-benzoyl-β-D-glucopyranoside (19) were favorably obtained by coupling a new donor, isopropyl 2-O-acetyl-3-O-allyl-4,6-O-benzylidene-1-thio-β-D-galactopyranoside (2), with acceptors, methyl 3-O-benzoyl-4,6-O-benzylidene-α-D-glucopyranoside (4), methyl 3,4,6-tri-O-benzoyl-α-D-glucopyranoside (5), methyl 3-O-benzoyl-4,6-O-benzylidene-β-D-glucopyranoside (8), and methyl 3,4,6-tri-O-benzoyl-β-D-glucopyranoside (12), respectively. By virtue of the concerted 1,2-cis α-directing action induced by the 3-O-allyl and 4,6-O-benzylidene groups in donor 2 with a C-2 acetyl group capable of neighboring-group participation, the couplings were achieved with a high degree of α selectivity. In particular, higher α/β stereoselective galactosylation (5.0:1.0) was noted in the case of the coupling of donor 2 with acceptor 12 having a β-CH(3) at C-1 and benzoyl groups at C-4 and C-6.

The synthesis of arbutin by use of thiolglycoside method was reported for the first time.Glucose was converted into a isopropyl 2,3,4,6-tetra-O-benzoyl-1-thio-β-D-glucopyranoside(donor) by acetylation,thiolation,deacetylation and benzoylation.Hydroquinone was selectively esterificated into two acceptors hydroquinone monoacetate,hydroquinone monobenzoate and related by-products(hydroquinone diesters).The donor was respectively coupled with two acceptors to afford two protected arbutins stereospecifically due to the effect of strong neighboring-group participation of C-2 benzoyl group,in which arbutin was obtained by use of deprotected methods respectively.All products were characterized by means of m.p.determination and 1HNMR analysis,etc.Additionally,two acceptors hydroquinone monoester could be obtained by effectively reusing the above by-products(diesters) via deacylating reaction.

Synthesis of N,N′-bis(2-salicyloyl)isophthalic acid dihydrazide(7) was synthesized with self-made salicylhydrazide(4) and isophthaloyl chloride(5) as raw materials,DMF as a solvent,triethylamine as an antacid,n(isophthaloyl chloride)∶n(salicylhydrazide) = 1.00∶2.75,for 9 h at 90 ℃,the yield was achieved 79.3%.At the same condition,N,N′-bis(2-salicyloyl)terephthalic acid dihydrazide(8) was synthesized,and the yield was 80.2%.The two products were confirmed by 1H NMR and MS etc.,and they were carried with TG analysis and applied research to PVC,and were shown a good thermal stability.

Lamivudine is a 2'-deoxy nucleoside analogue with a biological importance of an anti-HIV and anti-HBV.On the comparison of two technologies that the intermediate menthyl dihydroxy glycoxylate was synthesized with bromoacetic acid or glycoxylic acid as a different raw material,the synthetic technology is discovered shorter steps and lower cost with glycoxylic acid as a raw material.Menthyl dihydroxy glycoxylate was reacted to cyclization with 2,5-dihydroxy-1,4-dithiane,subsequent chlorinated,coupled,and reduced to obtain lamivudine.Meanwhile,the synthesis and separation technology was improved,and the overall yield is reached 22.5%.The improved technology herein is applicable to industrial production as the advantage of shorter steps,concise and practical operation.

The chemical synthesis of L-menthylβ-D-galactoside by thioglycoside method was reported for the first time.Galactose was converted into isopropyl 2,3,4,6-tetra-O-benzoyl-1-thio-β-D-galactoside(donor) by acetylation,thiolation,deacetylation and benzoylation.The donor was coupled with L-menthol,and deprotected to obtain L-menthylβ-D-galactoside.All products were characterized by means of NMR,MS analysis,etc.Additionally,TG analysis was employed for the thermal weight-loss process of the synsthesized L-menthylβ-D-galactoside.