Tetramethyl 1,1 (cid:48) -(2-[{4,5- bis (Methoxycarbonyl)-1 H -1,2,3-triazol-1-yl}methyl]-2-[(4-methylphenyl)sulfonamido]propane-1,3-diyl) bis (1 H

: A new compound tetramethyl 1,1 (cid:48) -(2-[{4,5- bis (methoxycarbonyl)-1 H -1,2,3-triazol-1-yl}methyl]-2-[(4-methylphenyl)sulfonamido]propane-1,3-diyl) bis (1 H -1,2,3-triazole-4,5-dicarboxylate) (3) was prepared in two steps starting from 2-((4-methylphenyl)sulfonamido)-2-((tosyloxy)methyl)propane-1,3-diyl bis (4-methylbenzenesulfonate) ( 1 ), with an overall yield of 74%. The key step being the copper-free Huisgen cycloaddition between N -(1,3-diazido-2-(azidomethyl)propan-2-yl)-4-methylbenzenesul-fonamide ( 2 ) and commercially available dimethyl acetylenedicarboxylate. The chemical structure of compound 3 was determined by IR, 1D and 2D NMR experiments, and elemental analysis.

The three O-tosylated groups are then substituted by the azide function via the action of 3,5 equivalents of sodium azide at reflux in acetonitrile for 24 h, leading to the N-tosyl triazide derivative (2) with a yield of 90% after recrystallization in ethyl acetate.
The three O-tosylated groups are then substituted by the azide function via the action of 3,5 equivalents of sodium azide at reflux in acetonitrile for 24 h, leading to the N-tosyl triazide derivative (2) with a yield of 90% after recrystallization in ethyl acetate.

Scheme 1. Synthetic route for compound (3).
The chemical structure of compound (3) was elucidated by methods of spectroscopic analysis such as 1D and 2D-NMR experiments, infrared spectroscopy, and elemental analysis. The 1 H NMR spectrum of the cycloadduct (3) showed the presence of two intense signals at 3.98 and 4.05 ppm corresponding to the 18 methyl protons of the ester groups. Also, the protons of the methylene group of compound (3), which resonate at 5.12 ppm, are more deshielded than those of the triazide derivative (2), which resonate at 3.52 ppm. All of this can be explained by the change in their chemical environment due to the tensions of the triazole rings. Furthermore, in the 13 C-NMR spectrum of compound (3), the assignment of the signals appearing at about 159.14 ppm and 159.97 ppm to the quaternary carbons of the carbonyl groups, and those appearing at about 132.48 ppm and 139.57 ppm to the quaternary carbons of the 1,2,3-triazole ring, also confirm that the 1,3-dipolar The chemical structure of compound (3) was elucidated by methods of spectroscopic analysis such as 1D and 2D-NMR experiments, infrared spectroscopy, and elemental analysis. The 1 H NMR spectrum of the cycloadduct (3) showed the presence of two intense signals at 3.98 and 4.05 ppm corresponding to the 18 methyl protons of the ester groups. Also, the protons of the methylene group of compound (3), which resonate at 5.12 ppm, are more deshielded than those of the triazide derivative (2), which resonate at 3.52 ppm. All of this can be explained by the change in their chemical environment due to the tensions of the triazole rings. Furthermore, in the 13 C-NMR spectrum of compound (3), the assignment of the signals appearing at about 159.14 ppm and 159.97 ppm to the quaternary carbons of the carbonyl groups, and those appearing at about 132.48 ppm and 139.57 ppm to the quaternary carbons of the 1,2,3-triazole ring, also confirm that the 1,3-dipolar cycloaddition reaction has taken place. In addition, the appearance of signals at approximately 52.89 ppm and 54.25 ppm in the case of the tris-triazole derivative (3) confirms the presence of methoxy groups of the ester function. The definite assignment of the chemical shifts of protons and carbons are shown in Table 1. The interpretation of the homonuclear and heteronuclear 2D-NMR spectra (Figures 1 and 2) of the cycloadduct (3) showed a perfect correlation, proton-proton and proton-carbon 13. cycloaddition reaction has taken place. In addition, the appearance of signals at approximately 52.89 ppm and 54.25 ppm in the case of the tris-triazole derivative (3) confirms the presence of methoxy groups of the ester function. The definite assignment of the chemical shifts of protons and carbons are shown in Table 1. The interpretation of the homonuclear and heteronuclear 2D-NMR spectra (Figures 1 and 2) of the cycloadduct (3) showed a perfect correlation, proton-proton and proton-carbon 13. The IR spectrum of compound (2), shows inter alia, a high-intensity band at 2100 cm −1 , characteristic for stretching vibrations of the azide group (-N3). Thus, in the spectrum of compound (3), we marked the absence of this last band and the presence of another at 3600 cm −1 , characteristic of triazole ring, and two high-intensity bands at 1700-1750 cm −1 , characteristics for vibrations of the carbonyl groups (C=O) of ester fragments. We also note the presence of the two other bands at 1350 cm −1 characteristics for stretching vibrations of the (C-O) bonds of ester functions. All of this clearly confirms that the cycloaddition reaction has been carried out.

Materials and Methods
All solvents were purified following the standard techniques and commercial reagents were purchased from Sigma-Aldrich (St. Louis, MO, USA). Melting point was determined with an electrothermal melting point apparatus and was uncorrected. NMR spectra ( 1 H and 13 C) were recorded on a Bruker AM 300 spectrometer (operating at 300 MHz for 1 H, at 75 MHz for 13 C) (Bruker Analytische Messtechnik & GmbH, Rheinstetten, Germany). NMR data are listed in ppm and are reported relative to tetramethylsilane ( 1 H, 13 C); residual solvent peaks being used as an internal standard. NMR spectroscopic data were recorded in CDCl3 using as internal standards the residual non-deuterated signal (δ = 7.26 ppm) for 1 H NMR and the deuterated solvent signal (δ = 77.16 ppm) for 13 C NMR spectroscopy. DEPT spectra were used for the assignment of carbon signals. Chemical shifts (δ) are given in ppm and coupling constants (J) are given in Hz. The following abbreviations are used for multiplicities: s = singlet, and d = doublet. All reactions were followed by TLC. TLC analyses were carried out on 0.25 mm thick precoated silica gel plates (Merck Fertigplatten Kieselgel 60F254) and spots were visualized under UV light or by exposure to vaporized iodine. The FT-IR spectrum was recorded in KBr pellet on a Bruker Vertex 70 FTIR spectrometer. Elemental analysis was performed with a Flash 2000 EA 1112, Thermo Fisher Scientific-Elemental Analyzer (CNRST-Rabat, Rabat, Morocco). The IR spectrum of compound (2), shows inter alia, a high-intensity band at 2100 cm −1 , characteristic for stretching vibrations of the azide group (-N 3 ). Thus, in the spectrum of compound (3), we marked the absence of this last band and the presence of another at 3600 cm −1 , characteristic of triazole ring, and two high-intensity bands at 1700-1750 cm −1 , characteristics for vibrations of the carbonyl groups (C=O) of ester fragments. We also note the presence of the two other bands at 1350 cm −1 characteristics for stretching vibrations of the (C-O) bonds of ester functions. All of this clearly confirms that the cycloaddition reaction has been carried out.

Materials and Methods
All solvents were purified following the standard techniques and commercial reagents were purchased from Sigma-Aldrich (St. Louis, MO, USA). Melting point was determined with an electrothermal melting point apparatus and was uncorrected. NMR spectra ( 1 H and 13 C) were recorded on a Bruker AM 300 spectrometer (operating at 300 MHz for 1 H, at 75 MHz for 13 C) (Bruker Analytische Messtechnik & GmbH, Rheinstetten, Germany). NMR data are listed in ppm and are reported relative to tetramethylsilane ( 1 H, 13 C); residual solvent peaks being used as an internal standard. NMR spectroscopic data were recorded in CDCl 3 using as internal standards the residual non-deuterated signal (δ = 7.26 ppm) for 1 H NMR and the deuterated solvent signal (δ = 77.16 ppm) for 13 C NMR spectroscopy. DEPT spectra were used for the assignment of carbon signals. Chemical shifts (δ) are given in ppm and coupling constants (J) are given in Hz. The following abbreviations are used for multiplicities: s = singlet, and d = doublet. All reactions were followed by TLC. TLC analyses were carried out on 0.25 mm thick precoated silica gel plates (Merck Fertigplatten Kieselgel 60F 254 ) and spots were visualized under UV light or by exposure to vaporized iodine. The FT-IR spectrum was recorded in KBr pellet on a Bruker Vertex 70 FTIR spectrometer. Elemental analysis was performed with a Flash 2000 EA 1112, Thermo Fisher Scientific-Elemental Analyzer (CNRST-Rabat, Rabat, Morocco).