异噻唑(啉)酮取代的间苯二甲酸衍生物的设计、合成及其抑制β-分泌酶活性

Design,synthesis and inhibitory activity against β-secretase of isothiazolone(isothiazolidine) substituted isophthalic acid derivatives

目的发现新结构的β-分泌酶抑制剂。方法基于β-分泌酶抑制剂的构效关系,设计合成了含羟乙胺结构片段的间位1,1-二氧代-2,3-(2H)-异噻唑酮和1,1-二氧代-异噻唑啉酮取代的间苯二甲酸衍生物;利用时间分辨荧光法(TRF)和中国仓鼠卵巢细胞(CHO,APP/BACE1基因)模型分别评价这些化合物体外抑制β-分泌酶和Aβ40的活性。结果合成了16个新目标化合物,利用MS和1H-NMR对化合物的结构进行了确证,利用HPLC对化合物的纯度进行了测定,利用旋光仪测定了化合物的比旋光度。活性数据显示,化合物2d、2e、2f、2g、2h和3d、3h抑制β-分泌酶活性的IC50值在10 nmol.L-1以下,化合物2c和3c、3g抑制β-分泌酶活性的IC50值在25 nmol.L-1以下;化合物2c、2d和2h在浓度为0.01μmol.L-1时,对双转APP/BACE1基因CHO细胞Aβ40产生的抑制率分别为58.3%、43.7%和42.1%。结论发现了新的β-分泌酶抑制剂,分析了其初步的构效关系,为进一步的结构优化以及发现活性更好的化合物提供了指导。

Alzheimer＇s disease（AD）,the neurodegenerative disorder,is the most common form of dementia and no disease modification therapy is currently available.It is characterized pathologically by the presence of intracellular neurofibrillary tangles（NFTs）and extracellular amyloid plaques.According to the amyloid cascade hypothesis,accumulation of amyloid peptides（Aβ） in the brain is the main component of senile plaques results in neuronal toxicity and cell death.That is considered to play a central role in the patho-logy and subsequent cognitive decline of AD.Aβ is produced from amyloid precursor protein（APP） by the sequential cleavage of the β-and γ-secretase.Because the initial proteolytic cleavage of APP by β-secretase（also known as BACE1,memapsin-2 or Asp-2） is considered to be the rate-limiting step in the processing of APP to Aβ,BACE1 has being considered to be an attractive therapeutic target to slow or halt the progression of AD.Based on the structural feature of active site of β-secretase binding to the typical inhibitors and the structure of β-secretase inhibitors discovered in our laboratory,new P2 isothiazolone（isothiazolidine） substituted isophthalic acids combining HEA isosteres as BACE1 inhibitors were designed and synthesized in this paper.Sixteen target compounds were synthesized and their structures were confirmed by 1H-NMR and MS.The purity of these compounds was determined by HPLC.The time-resolved fluorescence technique was used to evaluate inhibitory activity of these compounds against BACE-1.For the potent inhibitors the BACE1 cellular activities were determined measuring production of secreted soluble Aβ40 in cultured HuAPPswe/HuBACE1 double transfection Chinese hamster ovary（CHO） cells.The results showed that the IC50 value of compound 2d,2e,2f,2g,2h,3d and 3h against β-secretase was low than 10 nmol·L-1 and 2c,3c and 3g was low than 25 nmol·L-1.The inhibitory rate of compounds 2c,2d and 2h against Aβ40 production was 58.3%,43.7% and 42.1% at 0.01 μmol·L-1 respectively.