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.
N,N'-bis(salicyloyl)sebacic acid dihydrazide was synthesized from salicylic hydrazide and sebacoyl chloride,or salicylic chloride and sebacic dihydrazide. The structure was characterized by 1H NMR,13C NMR,MS and elemental analysis. The appropriate reaction conditions in DMF at 90 ℃ for 7 h were as follows:sebacoyl chloride was 13 mmol; n(salicylic hydrazide) ∶n(sebacoyl chloride) was 2.2 ∶1.0; triethylamine was used as an antacid. The yield reached 80% under the conditions.