鄭玉國, 薛 偉, 熊 壯, 何 勇, 楊 濤, 盧 平

(1. 貴州大學(xué) 精細(xì)化工研究開發(fā)中心 教育部綠色農(nóng)藥與農(nóng)業(yè)生物工程重點(diǎn)實(shí)驗(yàn)室,貴州 貴陽 550025; 2. 興義民族師范學(xué)院 化學(xué)生物系,貴州 興義 562400)

雙酰胺類化合物具有抗癌活性[1～6]；雜環(huán)化合物也成為新藥研究的重要對(duì)象,其中苯并噻唑類化合物具有抗真菌、抗結(jié)核、抗癌等藥理活性[7～15], 在醫(yī)藥研究領(lǐng)域引起廣泛關(guān)注。

本文采用活性拼接原理，以2,4-二氟苯甲酸(1a)或2-氟苯甲酸(1f)為起始原料，將苯并噻唑基引入雙酰胺結(jié)構(gòu)中，設(shè)計(jì)并合成了9個(gè)新型的N-[2-(取代苯并噻唑-2-氨基甲?；?苯基]取代氟基苯甲酰胺(6a～6i, Scheme 1)，其結(jié)構(gòu)經(jīng)1H NMR,13C NMR, IR和元素分析表征。

采用MTT法對(duì)6a～6i進(jìn)行抑制PC3癌細(xì)胞體外活性測(cè)試, 結(jié)果表明6a～6i具有不同程度的抑制PC3癌細(xì)胞活性,其中10 μmol·L-16b對(duì)PC3的抑制率為69.9%。

1 實(shí)驗(yàn)部分

1．1 儀器與試劑

X-5型熔點(diǎn)儀(溫度未校正);JEOL-ECX 500 NMR型核磁共振儀(DMSO-d6為溶劑，TMS為內(nèi)標(biāo));IR Prestige-21型紅外光譜儀(KBr壓片);Elementar Vario-Ⅲ型元素分析儀。

所用試劑均為分析純。

1.2 合成

(1) 2-(2,4-二氟苯甲酰胺)苯甲酸(3a)和2-(2-氟苯甲酰胺)苯甲酸(3f)的合成

在單口圓底燒瓶中加入2,4-二氟苯甲酸(1a) 3 mmol和二氯亞砜6 mL，攪拌下回流反應(yīng)12 h。減壓蒸除過量的二氯亞砜制得2,4-二氟苯甲酰氯(2a)。

在三口圓底燒瓶中加入鄰氨基苯甲酸3 mmol和二氯甲烷40 mL，攪拌下滴加三乙胺2 mL，滴畢，冰浴冷卻下緩慢滴加2a的二氯甲烷(15 mL)溶液，滴畢，于室溫反應(yīng)至終點(diǎn)[TLC跟蹤,展開劑A:V(石油醚) ∶V(乙酸乙酯)=1 ∶1]。加飽和氯化鈉溶液40 mL，用乙酸乙酯(2×40 mL)萃取，合并萃取液，依次用稀鹽酸、飽和碳酸氫鈉溶液和飽和氯化鈉溶液洗滌，無水Na2SO4干燥，減壓脫溶得3a粗品，烘干，不純化直接用于下一步反應(yīng)。以2-氟苯甲酸(1f)代替1a,用類似方法合成3f。

(2) 2-(2,4-二氟苯基)-4(3H)-3,1-取代苯并噁嗪酮(4a)和2-(2-氟苯基)-4(3H)-3,1-取代苯并噁嗪酮(4f)的合成

在裝有分餾器(200 mm)和蒸餾裝置(裝無水氯化鈣干燥管)的反應(yīng)瓶中加入3a100 mmol，醋酐100 mL,控制回流速度(約每10秒1滴)反應(yīng)至終點(diǎn)(TLC跟蹤，展開劑A)。冷卻至室溫，抽濾，濾餅干燥得白色晶體4a，不純化直接用于下一步反應(yīng)。用類似方法合成4f。

(3)6的合成(以6a為例)

在反應(yīng)瓶中依次加入4a5 mmol,乙腈40 mL和K2CO30.7 g(5 mmol),攪拌下回流反應(yīng)5 min;慢慢加入6-甲氧基苯并噻唑胺(5a) 5 mmol的乙腈(15 mL)溶液,加畢，回流反應(yīng)反應(yīng)至終點(diǎn)(TLC跟蹤，展開劑A)。傾入冷水中靜置析晶，抽濾，濾餅經(jīng)柱層析[洗脫劑：V(石油醚) ∶V(乙酸乙酯)=2 ∶1]純化得6a。

用類似方法合成6b～6i。合成6的實(shí)驗(yàn)結(jié)果見表1，表征數(shù)據(jù)見表2。

表 1 合成6的實(shí)驗(yàn)結(jié)果Table 1 Experimental results of synthesizing 6

表 2 6的表征數(shù)據(jù)Table 2 Characteristic data of 6

續(xù)表2

Comp1H NMR δ(J/Hz)13C NMR δIR ν/cm-16e12.96(s, 1H, NH), 11.09(s, 1H, NH), 7.74(s, 2H, ArH), 7.39(s, 3H, ArH), 7.28(s, 2H, ArH), 7.05(d, J=8.0, 2H, ArH), 6.93(d, J=8.0, 2H, ArH)173.0, 169.4, 152.6, 132.3, 130,7, 130.2, 125.9, 124.43 479, 3 331, 1 680, 1 652, 1 614, 1 585, 1 550, 1 523, 1 496, 1 446, 1 280, 1 251, 1 2246f12.89(s, 1H, NH), 11.15(s, 1H, NH), 8.32(s, 1H, ArH), 8.01(s, 1H, ArH), 7.88(d, J=7.5, 1H, ArH), 7.80(d, J=7.5, 1H, ArH), 7.65(d, J=6.9, 3H, ArH), 7.45～7.36(m, 2H, ArH), 7.32～7.27(m, 2H, ArH), 2.42(s, 3H, CH3)162.4, 160.9, 158.9, 134.3, 134.2, 133.8, 133.3, 131.2, 130.2, 128.2, 125.5, 124.4, 123.6, 123.5, 123.4, 122.1, 117.2, 116.9, 21.53 360, 3 232, 3 064, 3 298, 1 653, 1 604, 1 585, 1 521, 1 452, 1 313, 1 292, 1 271, 921, 812, 7526g13.00(s, 1H, NH),11.16(s, 1H, NH), 8.29(s, 1H, ArH), 8.00(d, J=8.0, 1H, ArH), 7.88(t, J=8.0, 1H, ArH), 7.75(s, 1H, ArH), 7.66～7.63(m, 2H, ArH), 7.48～7.33(m, 6H, ArH)162.4, 160.9, 158.9, 134.3, 134.2, 133.4, 131.2, 126.9, 125.5, 124.3, 117.2, 117.03 213, 3 188, 1 661, 1 653, 1 541, 1 496, 1 462, 1 442, 1 404, 1 340, 1 305, 1 271, 1 224, 1 097, 1 066, 914, 900, 7466h13.09(s, 1H, NH), 11.18(s, 1H, NH), 8.23(s, 1H, ArH), 7.93(dd, J=2.9, 2H, ArH), 7.87(t, J=8.0, 1H, ArH), 7.78(s, 1H, ArH), 7.66～7.65(m, 2H, ArH), 7.44～7.37(m, 2H, ArH), 7.35～7.30(m, 2H, ArH)162.4, 134.3, 134.2, 133.4, 131.2, 130.1, 125.4, 124.5, 123.6, 123.5, 117.1, 116.9, 114.9, 114.83 182, 3 064, 1 664, 1 606, 1 585, 1 550, 1 527, 1 456, 1 317, 1 290, 1 193, 1 074, 908, 852, 7546i14.41(s, 1H, NH), 13.10(s, 1H, NH), 8.64(d, J=8.1, 1H, ArH), 8.22～8.21(m, 2H, ArH), 7.84(s, 1H, ArH), 7.63～7.62(m, 1H, ArH), 7.53～7.36(m, 4H, ArH), 7.27(d, J=8.6, 1H, ArH), 7.17(t, J=8.1, 1H, ArH)170.7, 162.6, 161.4, 159.4, 151.9, 149.5, 133.6, 131.0, 130.9, 125.4, 125.3, 123.1, 120.9, 120.6, 117.3, 117.13 082, 3 030, 2 850, 1 687, 1 643, 1 589, 1 512, 1 463, 1 435, 1 404, 1 381, 1 273, 1 220, 1 134, 925, 759, 686

2 結(jié)果與討論

2.1 6的表征

以6a為例,IR譜圖中兩組酰胺鍵由于所處的化學(xué)環(huán)境不同，受外部基團(tuán)的影響也不同，因此N-H和C=O峰都出現(xiàn)兩組伸縮振動(dòng)峰。由于酰胺基氮原子的孤對(duì)電子垂直于芳環(huán)的π軌道，這使得氮原子不能與芳環(huán)有效共軛，進(jìn)而酰胺氮原子可能會(huì)與羰基形成有效的共軛，降低羰基中C=O的能量，引起羰基的IR吸收波數(shù)降低(1 662 cm-1)。與噻唑環(huán)相鄰的酰胺鍵中的C=O受噻唑環(huán)及氨基的共同影響，伸縮振動(dòng)波數(shù)也較低(1 632 cm-1)。3 406 cm-1與3 323 cm-1為N-H伸縮振動(dòng)，686 cm-1左右為C-S-C伸縮振動(dòng)。1H NMR譜圖上出現(xiàn)兩組NH質(zhì)子峰(12.87和11.17)，說明6a中出現(xiàn)兩個(gè)-CONH基, 其中一個(gè)-CONH基受噻唑環(huán)的影響,向低場移動(dòng)(12.87)。6b～6i的譜圖也呈現(xiàn)類似規(guī)律。

2.2 6的體外抗癌活性

6的抗癌活性測(cè)試以DMSO為參照物，阿霉素(ADM)為陽性對(duì)照藥劑。采用MTT比色法測(cè)定了6對(duì)人體前列腺癌細(xì)胞(PC3)的抑制率。將PC3細(xì)胞接種于96孔細(xì)胞培養(yǎng)板中，每孔2 200個(gè)細(xì)胞。于37 ℃在5%CO2飽和濕度下培養(yǎng)24 h，加入含處理因子的1 640培養(yǎng)基(200 μL/孔)。設(shè)空白對(duì)照和溶媒對(duì)照，每組4個(gè)平行，繼續(xù)培養(yǎng)72 h，加入5 mg·mL-1MTT 20 μL培養(yǎng)4 h，于酶標(biāo)儀上于570 nm處測(cè)定OD值。最后以溶媒對(duì)照組作參比計(jì)算抑制率,結(jié)果見表3。從表3可以看出，苯環(huán)上的取代基的電性對(duì)PC3癌細(xì)胞的抑制活性有一定的影響。當(dāng)R為2,4-F2時(shí)(6a～6e)對(duì)PC3癌細(xì)胞的抑制活性比R為2-F時(shí)(6f～6i)高；R′為6-F和6-Cl時(shí)(6b,6d,6h和6i)對(duì)PC3癌細(xì)胞的抑制活性比R′為其它取代基時(shí)高。6b和6d對(duì)PC3細(xì)胞的抑制活性相對(duì)較高，抑制率分別為69.6%和62.3%, 有進(jìn)一步優(yōu)化的潛力。這可能是取代基的吸電子誘導(dǎo)效應(yīng)引起了6分子上電荷分布的變化，使其更容易與受體結(jié)合。

表 3 6對(duì)PC3細(xì)胞的抑制活性*Table 3 Inhibition rates of 6 to PC3 cell

*c=10 μmmol·L-1

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