A convenient two-step method for the preparation of β3-amino acids is described.  This paper describes an efficient and straightforward two-step synthetic sequence leading in excellent yields to a relatively inaccessible lipophilic β3-amino acids with antimicrobial potential  from easily available starting materials. Schmidt reaction of substituted piperidin-4-ones with HN3 generated in situ afforded the corresponding diazapinones. Acid hydrolysis of chosen diazapinones yielded β3-amino acids. Selective cleavage of only the lactam bond is achieved using 4N HCl-MeOH (1:1) mixture   leading to the formation of N-alkyl β3-amino acids in quantitative yields. synthesized  aminoacids are subjected to antimicrobial activity for gram positive, gram negative bacteria, fungi. compounds  3e & 3h  possess excellent antimicrobial and antifungal activity comparable to standard streptomycin and ketoconazole. Therefore obtained β3-amino acids serves as a scaffold for  synthetic  antibiotics  as they have desired structural moieties necessary for antibiotic action. Further refinement of  the β3-amino acids  using  either conjugation or structural modification or incorporation of these aminoacids into synthetic peptides would bring about excellent antimicrobial activity.