Data mining algorithm in the identification of accounting fraud by smart city information technology.

The identification of accounting fraud is an important measure to safeguard the interests of stakeholders and ensure the long-term development of the company. The current traditional methods for identifying accounting fraud rely on manual review and judgment, lacking objectivity and accuracy. In order to improve the accuracy of accounting fraud identification, improve identification efficiency and objectivity, this article combines smart city information technology to conduct in-depth research on data mining algorithms for accounting fraud identification. This article first provides a brief overview of smart cities and information technology, then introduces the basic theory of accounting fraud identification, and finally implements accounting fraud identification through k-means clustering mining algorithm. The data is divided into k clusters, and abnormal clusters are identified by checking the characteristics and attributes of each cluster. Compared with traditional rule-based and pattern based methods, this approach can more flexibly adapt to different types and forms of fraud, and can discover unknown patterns of fraud. In the experiment, this article used electronic data collection, analysis, and retrieval systems on the websites of the Shanghai Stock Exchange and Shenzhen Stock Exchange to collect 641 annual reports and financial characteristics from 62 listed companies that engaged in financial statement fraud and 84 companies that were not reported to have financial statement fraud from 2012 to 2021 as test samples. The results were tested and analyzed from several aspects, including the number of misjudgments, misjudgment rate, and ROC curve. The final test results show that compared to traditional accounting fraud identification methods, the comprehensive misjudgment rate of data mining algorithms based on smart cities has decreased by 3 %. The conclusion indicates that data mining algorithms used in smart city information technology to identify accounting fraud can help improve the accuracy of accounting fraud, improve audit objectivity and effectiveness.

Structure-based design, synthesis, and memapsin 2 (BACE) inhibitory activity of carbocyclic and heterocyclic peptidomimetics.

Molecular modeling based on the X-ray crystal structure of the Tang-Ghosh heptapeptide inhibitor 1 (OM99-2) of BACE led to the design and synthesis of a series of constrained P(1)' analogues. A cyclopentane ring was incorporated in 1 spanning the P(1)' Ala methyl group and the adjacent methylene carbon atom of the chain. Progressive truncation at the P(2)'-P(4)' sites led to a potent truncated analogue 5 with good selectivity over Cathepsin D. Using the same backbone replacement concept, a series of cyclopentane, cyclopentanone, tetrahydrofuran, pyrrolidine, and pyrrolidinone analogues were synthesized with considerable variation at the P and P' sites. The cyclopentanone and 2-pyrrolidinone analogues 45 and 57 showed low nM BACE inhibition. X-ray cocrystal structures of two analogues 5 and 45 revealed excellent convergence with the original inhibitor 1 structure while providing new insights into other interactions which could be exploited for future modifications.

Stereoselective synthesis of constrained oxacyclic hydroxyethylene isosteres of aspartic protease inhibitors: aldol and Mukaiyama aldol methodologies for branched tetrahydrofuran 2-carboxylic acids.

The synthesis of diastereomeric 3-substituted-tetrahydrofuran 2-carboxylic acids in enantiopure form was achieved relying on aldol condensations of N-substituted alpha-amino aldehydes with enolates and enol silyl ethers of gamma-butyrolactone. Catalytic YbFOD leads to a high yield of a syn/syn-alpha-amino alcohol isomer. This was used as a constrained THF subunit in the synthesis of a peptidomimetic intended as an inhibitor of the enzyme BACE1, which is implicated in the cascade of events leading to plaque formation in Alzheimer's disease.

Stereoselective synthesis of constrained azacyclic hydroxyethylene isosteres as aspartic protease inhibitors: dipolar cycloaddition and related methodologies toward branched pyrrolidine and pyrrolidinone carboxylic acids.

The synthesis of three vicinally substituted azacyclic carboxylic acids in enantiopure form was achieved from a common alpha-amino aldehyde originating from l-leucine. Pyrrolidines and pyrrolidinones were elaborated from alpha,beta-unsaturated gamma-hydroxy-delta-amino acids via azomethine ylide 1,3-dipolar addition and conjugate addition/cyclization strategies, respectively. The azacyclic amino acids were incorporated in a pseudopeptide now encompassing a hydroxyethylene isostere. Low nanomolar inhibition of BACE1, an enzyme implicated in the cascade of events leading to plaque formation in Alzheimer's disease, was found with a pyrrolidinone analogue.