## 4 Conclusions  
Four compounds carrying the 4-amino-5-mercapto-1,2,4-triazoleol-3-yl moiety were synthesized, characterized and evaluated for their biological activity. The synthesis of 1,n-bis-(4-amino-5-mercapto-1,2,4-triazoleol-3-yl) alkanes was carried out by a new method, previously employed in our research group for the synthesis of 3-substituted-4-amino-5-mercapto-1,2,4-triazoleoles. In this study, simple and highly accessible starting reagents were used, namely, the dihydrazides of oxalic, malonic, succinic and adip acids, using mercaptoacetic acid dianion as a leaving group. Initially, the compounds were characterized by elemental analysis, which confirmed the theoretical composition, and by FTIR spectroscopy, which revealed the existence of characteristic bands of the moieties from bis-triazole structures. Although the compounds were obtained with modest yields (12-60%), their purity was high. Later, \({}^{1}\)H-NMR and \({}^{13}\)C-NMR spectroscopy were employed, the spectral results confirming the identity and purity of the designed compounds. The last part of our study aimed toward determining the stability profile of these compounds under controlled thermal stress in oxidative atmosphere. The biological activity evaluation consisted of studying the anticancer activity against the A375 line (human malignant melanoma), as well as on viability of the BJ fibroblast cell line, using MTT and LDH assays. As future directions of research, we aim toward optimization of the reaction yields and extend the homolog series of the bis-triazolees by using long-chained dicarboxylic acids. Also, a study for the reaction mechanism of this synthetic protocol will be investigated. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app14146180/s1](https://www.mdpi.com/article/10.3390/app14146180/s1)]([https://www.mdpi.com/article/10.3390/app14146180/s1](https://www.mdpi.com/article/10.3390/app14146180/s1)). Figure S1. FT-IR spectra of 1a, 4-amino-5-mercapto-3-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)-1,2,4-triazoleole; Figure S2. \({}^{1}\)H-NMR spectra of 1a, 4-amino-5-mercapto-3-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)-1,2,4-triazoleole; Figure S3. \({}^{13}\)C-NMR spectra of 1a, 4-amino-5-mercapto-3-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)-1,2,4-triazoleole; Figure S4. 2D COSY \({}^{1}\)H-\({}^{13}\)C spectra of 1a, 4-amino-5-mercapto-3-(4H-4-amino-5-mercapto-3-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)-1,2,4-triazoleole; Figure S5. \({}^{13}\)C-RMN DEPT-135 spectra of 1a, 4-amino-5-mercapto-3-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)-1,2,4-triazoleole; Figure S6. 2D HMBC NMR spectra of 1a, 4-amino-5-mercapto-3-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)-1,2,4-triazoleole; Figure S7. FT-IR spectra of 1b, 1,1-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)methane; Figure S8. \({}^{1}\)H-NMR spectra of 1b, 1,1-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)methane; Figure S9. \({}^{13}\)C-NMR spectra of 1b, 1,1-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)methane; Figure S10. FT-IR spectra of 1c, 1,2-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)ethane; Figure S11. \({}^{1}\)H-NMR spectra of 1c, 1,2-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)ethane; Figure S12. \({}^{13}\)C-NMR spectra of 1c, 1,2-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)ethane; Figure S13. \({}^{13}\)C-NMR spectra of 1c, 1,2-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)ethane; Figure S13. \({}^{13}\)C-NMR spectra of 1c, 1,2-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)ethane; Figure S14. \({}^{1}\)H-NMR spectra of 1d, 1,4-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-3-yl)butane; Figure S14. \({}^{1}\)H-NMR spectra of 1d, 1,4-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-5 yl)butane; Figure S15. \({}^{13}\)C-NMR spectra of 1d, 1,4-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-5 yl)butane; Figure S16. 2D COSY \({}^{1}\)H-\({}^{13}\)C spectra of 1d, 1,4-bis-(4H-4-amino-5-mercapto-1,2,4-triazoleol-5 yl)butane; Figure S17.