The drug-like database from ZINC [38] was screened by using Glide5 for its near-optimal performance aimed on targeting the HA1 receptor (PDB ID:3AL4). The top hit (ZINC01602230) or (2amino-N-(7H-purin-6-yl) acetamide) (Fig. 2) , a compound condensation product of Glycine and Adenine, which was considered as the most potential lead compound for further modification. Subsequently, the core hopping method was employed to search the fragment database for replacing the adenine part. Finally, the new structure Neo was discovered that has more strong affinity than ZINC01602230.