Study on synthesis of hybrid compounds of some triterpenoids containing benzamide and hydroxamate groups

and refining processes, the physical properties of the products received are: melting point, morphology, color, reaction performance and detailed data of spectra IR, HRMS, 1H-NMR, 13C- NMR, LC-MS/MS. Going from derivatives of some triterpenoids, we have synthesized 2 reaction sequences: 1 sequence of triterpenoid hybrid compounds containing benzamide group and 1 sequence of triterpenoid hybrid compounds containing hydroxamate group. The optimal method of using these compounds is to use a carboxylic group activator, BOP and a catalyst, DMAP, in a weak base medium, Et3N, and a reactive agent are amines in DMF solvent. We evaluated the cytotoxic activity of synthetic compounds on two human cancer cell lines, KB and Hep-G2. Chapter 3 : RESULTS AND DISCUSSION 3.1. The goal of the subject First perform the –OH group transformations at C-28 of some triterpenoids to form ester and amide derivatives, then react with different amines to form new compounds containing the group. benzamide and hydroxamate. Some triterpenoid compounds are directly reacted at C-28 with different amines as shown in figure 3.1. . 5 Scheme 3.1: The goal of the thesis 3.2. Synthesized results of hybrid compounds of some triterpenoids containing benzamide group 3.2.1.Synthesized results of betulin-containing hybrid compounds containing benzamide group via ester bridge To synthesize benzamide derivatives via ester bridges, the thesis first synthesized ester derivatives of betulin. Betulin (1) is reacted with carboxylic acid anhydride with a molar ratio of 1: 4 in anhydrous CH2Cl2 solvent with a alkaline catalyst of triethyl amine, in a reaction time of 24 hours. The 76a-f acid derivatives are white crystals, with a synergistic efficiency of 60% to 79%. The infrared (IR) spectrum of 76a compounds showed a absorption pattern at 1732 and 1642 cm-1, which was characteristic of the -C = O group in the ester and acid functional groups while the infrared spectrum of betulin did not appear 6 this absorption pattern. On the 1H-NMR proton resonance spectrum Scheme 3.2: Sơ đồ tổng hợp các chất 77a-e the doublet doublet resonance signal of the H-3 proton (3.19 ppm) with J = 11 and 5 Hz, the signals at Ha-28 and Hb-28 appear at 4.31 and 3.90 ppm respectively; 1H singlet signals of Ha-29 and Hb-29 appear at 4.68 and 4.58 ppm, 6 methyl groups appear fully with singlet signals at 0.75 - 1.68 ppm, signals this does not change much from the standard spectrum of betulin. In addition, on the proton spectrum of compound 76a, there are also full branched protons (2.71-2.64 ppm, 2H-2 'and 2H-3'). Particularly for 76e, the reaction agent is cis-1,2,3,6-tetrahydro phtalic anhydride when reacting with betulin to form 76e ester derivative, showing that two resonant signals of each proton Ha-28 and Hb -28 was split into two doublet signals with the intensity of 0.5H, the interaction constant J is 11.0 Hz, which confirms the cis configuration in the double connection of acid anhydride cis-1,2,3,6-tetrahydro phtalic has been converted into a trans configuration in compound 76e by reacting with this anhydride acid to betulin. Other compounds have been shown similarly. Comparison of these spectral analysis results with reference [66] can confirm that the structure of 76a-f ester derivatives is consistent with chromatography on spectroscopy. 7 Figure 3.1: Chemical structure and some physical characteristics of 76a-f compounds From the ester derivatives of acid 76a-e, continue to be reacted with 1,2-diaminobenzene (molar ratio of 1: 1.5) in DMF solvent in the presence of BOP / DMAP / Et3N received 77a-e products. The -COOH acid group is converted to the amide group, this reaction occurs quickly and has high efficiency, the product of a very selective reaction. The structure of 77a-e products is confirmed by spectral data. On the IR spectrum of compound 77c, the absorption peak at 3373 cm-1 is typical of the -NH group and there is the strong absorption peak of the -C = O group on the amide group at 1655 cm-1. On the 1H-NMR spectrum of compound 77c, in addition to the signals of the lupan frame, there are additional signals of the 8 benzamide group as in the singlet 1H signal (7.55 ppm) of the -NH group. The signal in the range of 7.18 - 6.76 ppm is of the aromatic ring, specifically the doublet doublet signal at 7.18 ppm (1H), the constant J = 1.5 Hz is of the H-6 proton; 7.06 ppm (1H, td, J = 7.5; 1.5 Hz, H-4 ”); 6.78 (1H, dd, J = 7.5; 2.0 Hz, H-3 ”) and 6.76 (1H, td, J = 7.5; 1.5 Hz, H-5”) ( figure 3.2) Figure 3.2: 1H-NMR relaxation spectrum of 77c compound On the 13C-NMR spectrum of 77c compound appears to push enough signals of the carbon atoms present in the molecule. In addition to the signals of the lupane frame, there are also signals of the carbonyl group of esters and amides and aromatic rings, specifically, as the signal 175,6 ppm is of the carbonyl group of esters (C-1 ’); at signal 172.7 ppm is of the carbonyl group of amide (C-4 ’); signals of carbon atoms in the aromatic ring are as follows: at signal 142.0 ppm, it is of C-2 ”; 127.5 is C-1 ”; 123,5 is C-6 ”; at signal 118.9 is C-5 ”; 117.2 is C-3 ”(figure 3.3). On the high resolution mass spectra of compound 77c found the m / z fragment [M + H] + is 661,4883 (figure 3.4) in accordance with the theoretical 9 calculated mass for C42H65N2O4 molecular formula of the compound 77c is 661.4866. Comparing these spectral analysis results with previously published references [38, 41, 42, 88-90] can confirm that the structure of 77c compound is consistent with the spectral data. The diagram and structure of 77a-b and 77d-e compounds were similarly confirmed. Figure 3.3: 13C-NMR relaxation spectrum of 77c compound Figure 3.4: Mass spectrometry LC-MS/MS of 77c compound C_92 #1377 RT: 4.68 AV: 1 NL: 3.64E7 T: FTMS + p ESI Full ms [50.0000-750.0000] 560 580 600 620 640 660 680 700 m/z 0 10 20 30 40 50 60 70 80 90 100 R e la ti v e A b u n d a n c e 661.48834 699.44305683.46967 664.49823 600.79724578.81519 706.54669622.78101 644.75861556.83197 10 Cơ chế hình thành hợp chất 77c đầu tiên là quá trình thế nguyên tử hydro của hợp chất 76c trong môi trường bazơ yếu là triethyl amine bằng nhóm (NMe2)3P- trong tác nhân hoạt hóa BOP để tạo thành hợp chất trung gian 76c1, tiếp theo dưới xúc tác DMAP hợp chất 76c1 được chuyển thành hợp chất trung gian 76c2 và sau đó là phản ứng thế bằng tác nhân thế ái nhân là 1,2-diaminobenzene để hình thành sản phẩm 77c (sơ đồ 3.3). Scheme 3.3: Mechanism of compound formation 77c 3.2.2. Synthesized results of hybrid compounds of pentacyclic triterpenoid diacid containing benzamide group By the same methods, the thesis synthesizes hybrid compounds of pentacyclic triterpenoid diacid containing benzamide group with the desire to search for new hybrid compounds with interesting biological activity. Diacid pentacyclic triterpenoid derivative 78a-b isolated from Cheffleraoctophylla (Ivy tree) [91] was reacted with Jone oxidant (Cr3O / H2SO4) in acetone solvent 11 which received oxidized products 79a-b [30, 31] (scheme 3.5). Compound 79b is then reacted directly with 1,2-diaminobenzen with a molar ratio of 1: 1,5 in DMF solvent in the presence of BOP / DMAP / Et3N to obtain compound 80 (scheme 3.4 ). Scheme 3.4: Synthesized of 80 compound On the 1H-NMR spectrum of compound 80, in addition to the signals of the lupan frame, there was also the signal of the -NH group Figure 3.5: 1H-NMR spectrum of 80 compound 12 at 7.47 ppm; signal of 4 aromatic ring protons at 7.08-6.78 ppm (Figure 3.5). On the 13C-NMR spectrum also appear full signal of lupan frame and aromatic ring. The two ketone groups of C-3 and C- 11 appear in the weak fields 213.2 and 210.8 ppm, the carbonyl C-28 group at 174.6 ppm, the aromatic carbon atoms appear in the region 118 , 5 - 140.9 ppm (figure 3.6). Figrue 3.6: 13C-NMR spectrum of 80 compound Figrue 3.7: LC-MS/MS spectrum of 80 compound C_82 #880 RT: 2.99 AV: 1 NL: 1.98E8 T: FTMS + p ESI SIM ms [542.5000-545.5000] 542.6 542.8 543.0 543.2 543.4 543.6 543.8 544.0 544.2 544.4 544.6 544.8 545.0 545.2 545.4 m/z 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 R el at iv e A bu nd an ce 545.3702 544.8902543.3550542.8172 13 The structure of compound 80 is also proved by mass spectra, on mass spectra of compound 80 found piece m / z [M + H] + is 545,3702 (Figure 3.7) in accordance with the calculated mass According to the theory for the molecular formula C35H49N2O3 of compound 80 is 545,3737. Compound 79a is deoxidized by reducing agent NaBH4 with molar ratio of 1: 4 in MeOH solvent at room temperature, C = O group at C-3 position is reduced to -OH group with 3β –hydroxy configuration. (compound 81) according to figrue 3.5. Figrue 3.5: Synthesized of 83a-b compounds The 1H-NMR nucleus resonance spectrum of 81 appears the signal of a proton doublet at δH 3.71 ppm (dd, J = 2.5 Hz, H-3β) typical for 3β-OH group in C-3 position. To protect this 3β-OH group, before reacting with 1,2-diaminobenzene, compound 81 was acetylated with acetic anhydride agent with mol ratio of 1: 1.5 in 14 DCM solvent, received product 3-acetyl products (82). Compound 82 was then reacted with 1,2-diaminobenzene with a mol ratio of 1: 1,5 in DMF solvent in the presence of BOP / DMAP / Et3N and obtained benzamide 83a (figrue 3.5). To obtain a new benzamide product, compound 83a continued to be hydrolyzed by LiOH agent in MeOH solvent to obtain compound 83b (figrue 3.5). The structure of 83a-b compounds was similarly confirmed by 1H-NMR and 13C-NMR spectrum. 3.2.3. Snthesized results of hybrid compounds of betulinic acid containing benzamide group Betulinic acid (2) is also a derivative of triterpenoid with many biological activities, so the thesis continues to explore the direction Figrue 3.6: Synthesized of 84 and 85 compounds direction study on synthesis of benzamide compounds from betulinic acid. Betulinic acid was reacted with 1,2-diaminobenzene in DMF 15 solvent in the presence of BOP / DMAP / Et3N received product 84 (figrue 3.6). Next, betulinic acid (2) is oxidized by the agent Jone (Cr3O / H2SO4) in acetone solvent to obtain compound 69 (figrue 3.6). The - OH group in carbon position 3 in the oxidized molecule, this is confirmed on the proton spectrum when the characteristic signal of H-3 protons does not appear on the spectrum of compound 69. In addition, on the IR spectrum of compound 69, the characteristic absorption signal of the cyclic ketone group appears at a wavelength of 1701 cm-1. Such data allow us to confirm the structure of compound 69 [30,31]. Compound 69 was then reacted with 1,2- diaminobenzene in DMF solvent in the presence of BOP / DMP / Et3N and received benzamide 85 (figrue 3.6). The structure of compounds 84 and 85 are similarly demonstrated. 3.2.4. Synthesized results of other triterpenoid hybrids containing benzamide Ursolic acid (3) and 3--acetoxy-21-oxolup-18-ene-28-oic acid (5) are also well-studied triterpenoid derivatives. Therefore, the thesis continues to study synthesis of benzamide compounds from these acids. The acetylated ursolic acid is similar to compound 81 to obtain compound 86. Then the compound 86 reacts with 1,2- diaminobenzene in DMF solvent in the presence of BOP / DMAP / Et3N received product 87 benzamide (figrue 3.7). The final compound, triterpenoid (5), was also reacted with 1,2-diaminobenzene with a mol ratio of 1: 1.5 in DMF solvent in the presence of BOP / DMAP / Et3N received 88a compound. Like compound 83a, compound 88a is also hydrolyzed by LiOH with a mol ratio of 1: 5 in MeOH solvent, receiving compound 88b (figrue 3.8), on the proton spectrum of compound 88b no longer see any signal 3H singlet effect at 2.05 ppm, this proves that the 3β-acetoxy group of compound 88a has been converted into 3β -hydroxy group in compound 88b. On the 1H-NMR spectrum of compound 87, in 16 addition to the signals of the ursan frame, there is a singlet 1H signal at 7.53 ppm of -NH group, 4 protons of the aromatic ring appear in the region from 7.13 to 6, 77 ppm (Figure 3.8). Scheme 3.7: Synthesized of 87 compound Scheme 3.8: Synthesized of 88a-b compounds On the 13C-NMR spectrum also appear full signal of carbon atoms, the carbonyl group at C-28 appears at 176.6 ppm, the carbonyl group (CH3C = O) appears at the signal of 171.0 ppm, 6 carbon atoms of the aromatic ring appears in the stronger field region, at the signal of 140.6 ppm is of C-2 '; at 126.6 ppm the signal is C-1 ’; at 17 signal 126.1 ppm is of C-4 ’; at 124.7 ppm the signal is C-6 ’; at signal 119.4 ppm is C-5 'and at signal 118.2 ppm is C-3' (Figure 3.9). Figrue 3.8: 1H-NMR spectrum 87 compound Figrue 3.9: 13C-NMR spectrum 87 compound 18 The structure of compound 87 is also demonstrated by high resolution mass spectra. On the high resolution mass spectra of compound 87 found the m / z fragment [M + H] + is 589,4329 (Figure 3.10) in accordance with the theoretical calculated mass for the molecular formula C38H57N2O3 of the compound 87 is 589,4363. Thus, based on the above data, it can be confirmed that the structure of compound 87 is consistent with the data on the graph. The structure of 88a-b compounds has been similarly proven by modern spectroscopic methods. Figrue 3.10: LC-MS/MS spectrum of 87 compound Thus, the thesis has successfully synthesized 13 hybrid compounds of some triterpenoids containing benzamide group and these are new and obtained compounds with high performance. The structure of the products has been demonstrated by modern spectroscopic methods such as IR, 1H-NMR, 13C-NMR and LC-MS / MS. 3.3. Synthesized results of hybridization compound of some triterpenoids containing hydroxamate group Although many derivatives of triterpenoid acid have been prepared and screened for their cytotoxic activity [92-99], the hybrid compounds of triterpenoid containing hydroxamate group are very C-94 #1690 RT: 5.74 AV: 1 NL: 1.65E8 T: FTMS + p ESI SIM ms [587.5000-590.5000] 587.6 587.8 588.0 588.2 588.4 588.6 588.8 589.0 589.2 589.4 589.6 589.8 590.0 590.2 590.4 m/z 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 R el at iv e A bu nd an ce 589.4329 590.4356 588.4661587.5426 19 little described so far. Hydroxamic acid is a widely studied group with inhibitory concentrations in the range of micromol to nanomol. Therefore, with the successful research on the process of synthesizing hybrid compounds of some triterpenoids containing benzamide group, by the same methods, the thesis continues to set the next research direction for synthesis of hybrid compounds. of some triterpenoids containing hydroxamate groups in order to find new compounds with interesting biological activity. 3.3.1. The result of synthesis of hybrid compounds of betulin containing hydroxamate group via ester bridge The ester derivatives 76a, 76b, 76e and 76f are obtained when betulin is reacted with different acid anhydrides (Fig. 3.2) which are reacted with H2NOH.HCl or HNMeOMe.HCl with a mol ratio of 1: 2 in DMF solvent in the presence of BOP / DMAP obtained 89a-h hydroxamate products (figrue 3.9). Scheme 3.9: Synthesized of 89a-h compounds 20 The structure of 89a-h compounds is proved by modern spectroscopic methods. Each molecule of these compounds contains functional group -CONHOH or -CONMeOMe (collectively called hydroxamate group). On the 1H-NMR spectrum of compound 89a, in addition to the full proton signal of the lupan frame, there is also a 1H singlet signal in the weak field area of 10.39 ppm which is the characteristic of group -NH, singlet 1H signal at 8.69 ppm is of -OH group in - CONHOH (Figure 3.11). On the 13C-NMR spectrum in addition to the signals of the lupane frame, especially the ester carbonyl group appears at 172.8 ppm, the carbonyl group at 168.3 ppm is the carbonyl group in -CONHOH (Figure 3.12). On the IR spectrum, the signal also appears at 3354 cm-1 with the sharp peak as a characteristic of the -NH group, in addition to the carbonyl group of C-28 ester at the signal of 1706 cm-1, an additional signal appears at 1698 cm -1 is for the carbonyl group in -CONHOH.. Figrue 3.11: 1H-NMR spectrum of 89a compound On the mass spectra of compound 89a found piece m / z [M + H] +: 558,3437 (Figure 3.13) which is suitable with the theoretical calculated weight for CTPT C34H56NO5 is 558,3458. Comparing 21 these spectral analysis results with previously published references [62, 63], it is possible to confirm the structure of compound 89a in accordance with spectral data. Figrue 3.12: 13C-NMR spectrum of 89 compound Figrue 3.13: LC-MS/MS spectrum of 89a compound C-B21L2 #5920 RT: 14.88 AV: 1 NL: 4.90E6 T: FTMS + p ESI SIM ms [556.5000-559.5000] 556.6 556.8 557.0 557.2 557.4 557.6 557.8 558.0 558.2 558.4 558.6 558.8 559.0 559.2 559.4 m/z 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 R e la ti v e A b u n d a n c e 558.3437 559.3469 557.5972 557.8488 558.1019557.3305 558.6008 559.0940556.5800 558.8276557.2203 22 Scheme 3.10:Mechanism of product formation 89a Figrue 3.14: 1H-NMR spectrum of 89b compound For 89b compound on 1H-NMR spectrum in addition to the signal of lupan frame, there is also a 3H singlet signal at 3.72 ppm 23 which is typical for the -NMe group and a 3H singlet signal at 3.17 ppm belongs to the group - OMe (Figure 3.14). On the 13C-NMR spectrum in addition to the -C = O group of esters (C-28) at the signal of 173.3 ppm, there is also an additional signal at 171.1 ppm of the - C = O group in the -CONMeOMe group (figure 3.15). On IR spectrum, there are two signals at 1733 and 1667 cm-1 belong to these two groups -C = O.. Figrue 3.15: 13C-NMR spectrum of 89b compound Figrue 3.16: LC-MS/MS spectrum of 89b compound C-B28 #4569 RT: 11.49 AV: 1 NL: 1.59E5 T: FTMS + p ESI SIM ms [584.5000-587.5000] 585.5 585.6 585.7 585.8 585.9 586.0 586.1 586.2 586.3 586.4 586.5 586.6 586.7 586.8 586.9 587.0 587.1 587.2 m/z 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 R el at iv e A bu nd an ce 586.2869 586.0152 586.7262 24 Compound 89b is also proved by high resolution mass spectra, on mass spectra found fragments m / z [M + H] +: 586,2869 (Figure 3.16) in accordance with the theoretical calculated mass for CTPT C36H60NO5 is 586,2866. Comparing with spectral data in some previously published documents [62, 63], it is possible to confirm the expected structure of compound 89b as shown on the graph. The structure of other compounds is similarly confirmed. 3.3.2. Results of hybrid compounds of some other triterpenoids containing hydroxamate group via amide bridge The first is the synthesis of amide derivatives 91, 93, 95: Betulinic acid (2), 3-acetoxy-21-oxolup-18-ene-28-oic acid (5), and compound 81 is reacted with 6-aminohexanoic acid with a mol ratio of 1: 2 in DMF solvent, in the presence of BOP and DMAP catalysts within a 24 hour period, obtained amide derivatives 91, 93, 95.) Figrue 3.17: 1H-NMR spectrum of 91 compound On the 1H-NMR spectrum of these compounds, in addition to the signals of the lupane frame, there is also a 1H triplet-patterned spectral signal corresponding to the displacement of 5.67-5.80 ppm (in CDCl3 solvent), This shows that the carboxylic groups of acids 2, 5 and 81 have been converted into amide groups (Figure 3.17). 25 Compounds 91, 93, 95 are then reacted with H2NOH.HCl or HNMeOMe.HCl with a mol ratio of 1: 2 in DMF solvent in the presence of BOP / DMAP to obtain 92a-b, 94a-b and 96a-b hydroxamate compounds (figrue 3.11; 3.12 and 3.13). Scheme 3.11: Synthesized of 90a-b, 92a-b compounds 26 Scheme 3.12: Synthesized of 94a-b compounds Scheme 3.13: Synthesized of 96a-b compounds The structure of these compounds is also proved by modern spectroscopic methods. In the 1H-NMR spectrum of compound 92a, in addition to the signals of the lupan frame, there is also a 1H singlet signal at 10.30 ppm which is a characteristic of the -NH group and a 27 1H singlet signal at 8.61 ppm belongs to the group - OH in hydroxamic group -CONHOH, also appears the 1H triplet signal at 7.37 ppm which is characteristic of -NH group in amide group at ankyl bridge (due to interaction with 2 protons of -CH2 group at position 1 '(the ankyl bridge part), so the spectrum is triplet-shaped and has a stronger field resonance) (Figure 3.18). Figrue 3.18: 1H-NMR spectrum of 92a compound Scheme 3.19: 13C-NMR spectrum of 92a compound 28 On the 13C-NMR spectrum of compound 92a in addition to the signal of 206.9 ppm of the ketone group and 170.1 of CH3CO-, there was also an additional signal of carbonyl group of amide at C- 28 at 173.1 ppm and carbonyl group. in the hydroxamic group at 172.8 ppm (Figure 3.19). On the high resolution mass spectra, we found the m / z piece [M + H] +: 641,4489 (Figure 3.20) in accordance with the theoretical calculation volume for CTPT C38H61N2O6 is 641.4429. Thus, the expected structure of 92a compound is suitable for the spectrogram. The structure of other compounds is similarly proven. Figrue 3.20: LC-MS/MS spectrum of 92a compound Experimental study of two protons in the hydroxamic functional group -CONHOH author Rachel Cold [100] showed that in a non-proton solvent such as DMSO, the H of N-H acts as a ptoton acid rather than N-OH. Because of the more flexibility, -NH resonates at the weaker field (δ = 10,30-12,37 ppm). Moreover, these protons are very flexible and easily exchanged or mutually exchanged, so some of the signal -NH, -OH signals are very weak like in the 89g compound, the two resonant signals of each proton - NH and -OH is separated into two doublet signals with the intensity C-44 #1146 RT: 3.90 AV: 1 NL: 6.78E8 T: FTMS + p ESI SIM ms [639.5000-642.5000] 639.6 639.8 640.0 640.2 640.4 640.6 640.8 641.0 641.2 641.4 641.6 641.8 642.0 642.2 642.4 m/z 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 R el at iv e A bu nd an ce 641.4489 642.4512 640.4673 29 of 0.5H or in some cases does not give signals on the spectrum as 89e. In addition to the above groups, another group of protons in the structure of the sequences is branched protons. Most substances have enough branched protons with the chemical shift of the -CH2 groups in the range of 1.25-3.94 ppm. The substances are measured in DMSO solvent, so due to the effect of proton of methyl group in incompletely deuterized DMSO solvent ( = 2.50 ppm), some protons in 2 protons of group -CH2 cannot be observed. signals at position of about 2.50 ppm. Thus, we have successfully synthesized 16 hybrid compounds of some triterpenoids containing hydroxamate group via ester bridge and amide bridge. The newly synthesized compounds have been proven by modern spectroscopy such as IR infrared spectroscopy, 1H-NMR and 13C-NMR nuclear magnetic resonance spectra, mass spectrometry LC-MS / MS. 3.4. Anticancer activity of hybrid compounds With the desire to synthesize biologically active hybrids in search of new compounds with anticancer activity, hybrid compounds of some triterpenoids containing benzamide and hydroxamate groups after being synthesized have been developed to test in vitro cytotoxic activity against two human cancer cell lines, KB (epithelial cancer) and Hep-G2 (liver cancer), along with the activity test of Ellipticine standard. The process of examining cytotoxic activity was conducted at the Department of Applied Biochemistry of Institute of Chemistry. Results of activity testing of compounds are presented in Table 3.1 and Table 3.2. 30 Table 3.1: Results of activity testing of hybrid compounds containing benzamide STT Compound IC50 (µM) KB IC50 (µM) Hep-G2 1 77a 202,2 202,2 2 77b 197,9 166,0 3 77c 193,7 115,6 4 77d 193,7 128,9 5 77e 186,9 108,0 6 80 214,0 234,9 7 83a 222,7 168,5 8 83b 240,2 176,8 9 84 15,4 12,1 10 85 234,9 234,9 11 87 216,6 158,7 12 88a 68,2 137,1 13 88b 152,5 209,0 14 Ellipticine 1,3 1,5 31 Table 3.2: Results of activity testing of hybrid compounds containing hydroxamate group STT Compound IC50 (µM) KB IC50 (µM) Hep-G2 1 89a 29,76 23,39 2 89b 55,71 9