郝甜甜 ,楊 堯,付 穎,呂洪彬,苗 愛,郭 娜, ,郁 彭
(1.天津科技大學(xué)生物工程學(xué)院,天津 300457;2.中國(guó)醫(yī)學(xué)科學(xué)院/北京協(xié)和醫(yī)學(xué)院藥物研究所天然藥物活性物質(zhì)與功能國(guó)家重點(diǎn)實(shí)驗(yàn)室,北京 100050)
早在19 世紀(jì)中葉,德國(guó)病理學(xué)家Rudolf Virchow 就已經(jīng)證明惡性腫瘤組織中有白細(xì)胞浸潤(rùn),認(rèn)為腫瘤可能源自慢性炎癥[1].腫瘤微環(huán)境中存在大量炎癥細(xì)胞和炎癥因子,對(duì)腫瘤細(xì)胞的增生、生存、轉(zhuǎn)移發(fā)揮重要作用,是腫瘤形成、發(fā)展和轉(zhuǎn)移過程中的重要促進(jìn)因素[2].能夠證明炎癥與癌癥間存在確定關(guān)系的證據(jù)之一是抗炎藥物能降低各種癌癥的發(fā)生風(fēng)險(xiǎn)、減慢腫瘤發(fā)展進(jìn)度、降低患者死亡率.例如流行病學(xué)研究表明,使用非甾體抗炎藥可將結(jié)腸癌風(fēng)險(xiǎn)降低40%~50%[3].
白三烯A4 水解酶(LTA4H)是炎癥通路中的一個(gè)關(guān)鍵酶,其在多種人類惡性腫瘤中高表達(dá),包括結(jié)直腸癌、食管癌、肺癌和甲狀腺癌等[4].因此,LTA4H 是抑制炎癥和腫瘤的一個(gè)潛在靶點(diǎn).人類白細(xì)胞的LTA4H 在1984 年首次被純化,并被鑒定為相對(duì)分子質(zhì)量為6.8×104~7.0×104的胞質(zhì)單體環(huán)氧水解酶(EH),具有EH 活性和依賴鋅離子的氨肽酶(AP)活性.兩種活性位點(diǎn)和底物結(jié)合口袋大部分重疊,因此很難設(shè)計(jì)高選擇性的抑制劑.盡管LTA4H 的上述兩種活性有各自的生理作用,但兩種活性都促進(jìn)腫瘤發(fā)生發(fā)展,即抑制兩種活性均有益于抗腫瘤[4].從21 世紀(jì)初期開始,對(duì)LTA4H 抑制劑的大部分研究主要涉及天然底物白三烯A4(LTA4)的類似物,深入研究發(fā)現(xiàn)其水解酶與氨肽酶的雙重活性均依賴鋅離子,由此開發(fā)了鋅離子螯合劑作為抑制劑.隨著對(duì)LTA4H 晶體結(jié)構(gòu)[5-7]的解析,人們開始基于計(jì)算機(jī)模擬來設(shè)計(jì)新型的LTA4H 抑制劑,其中DG-051 是曾進(jìn)行至二期臨床研究的一個(gè)抑制劑[8-9],其水解酶活性的IC50達(dá)到70 nmol/L[10-11],其與LTA4H 結(jié)合的共晶X 射線圖清晰展示了二者的作用模式[11].
新型LTA4H 抑制劑在抗炎和炎癥相關(guān)的腫瘤治療領(lǐng)域具有重要研究?jī)r(jià)值,而抗炎藥物和傳統(tǒng)抗癌藥物的組合更有望在癌癥治療中發(fā)揮作用.本研究擬以吲哚為母核,在前期構(gòu)效關(guān)系和DG-051 相關(guān)研究基礎(chǔ)上,設(shè)計(jì)合成一系列新型LTA4H 抑制劑.挑選LTA4H 抑制活性較好的化合物與抗癌藥物紫杉醇共價(jià)偶聯(lián),所制備的偶聯(lián)物可以看作“孿藥”和“前藥”的結(jié)合體.LTA4H 的抑制劑既可以通過抑制炎癥改善腫瘤治療效果,還有望通過與腫瘤部位高表達(dá)的LTA4H 相結(jié)合起到靶向腫瘤部位的作用,使紫杉醇在腫瘤部位富集,起到增效減毒的效果.
癌細(xì)胞來自國(guó)家實(shí)驗(yàn)細(xì)胞資源共享服務(wù)平臺(tái)(北京).生物試劑,賽默飛世爾科技公司;白三烯B4(LTB4)檢測(cè)試劑盒,Cayman 公司;化學(xué)試劑均為分析純,安耐吉化學(xué)試劑有限公司;溶劑均為分析純,天津市江天化工技術(shù)有限公司;infinite F50 型基礎(chǔ)酶標(biāo)儀,帝肯(上海)貿(mào)易有限公司;AV400 型核磁共振波譜儀,布魯克光譜儀器公司.
1.2.1 吲哚衍生物的合成
共設(shè)計(jì)合成兩類吲哚衍生物,兩類衍生物的合成方法相似,僅1 位和5 位取代基修飾類型、反應(yīng)順序及反應(yīng)條件略有差異.
第一類吲哚衍生物是以5-羥基吲哚為原料,先用Boc 基團(tuán)保護(hù)1 位,在堿性條件下1 位酚羥基與芳香取代基生成醚鍵,再將1 位脫除保護(hù)基,通過親核取代反應(yīng)分別連接各種極性基團(tuán),生成化合物2-10 至2-17,其中2-10 和2-11 通過硼氫化鈉還原可得化合物2-18 和2-19.
第二類吲哚衍生物是在將1 位用Boc 保護(hù)后,先通過親核取代在5 位連接氯乙基基團(tuán),再用各種極性取代基分別取代氯原子,生成5 位取代的吲哚,再脫除1 位保護(hù)基,最后在1 位連接各類疏水性芳香取代基,得到化合物2-29 至2-46.
所有化合物經(jīng)NMR、HRMS 確認(rèn)結(jié)構(gòu),并用HPLC 分析純度,其合成路線圖及反應(yīng)條件如圖1 和圖2 所示.
圖1 第一類吲哚衍生物的合成路線Fig.1 Synthetic route of the first type of indole derivatives
圖2 第二類吲哚衍生物的合成路線Fig.2 Synthetic route of the second type of indole derivatives
1.2.2 吲哚衍生物與紫杉醇偶聯(lián)物的合成
從上述兩個(gè)系列的吲哚衍生物中分別選擇了兩個(gè)LTA4H 抑制活性較好的化合物(2-18 和2-51)用于與紫杉醇進(jìn)行偶聯(lián),第一類衍生物中的2-18 可以通過分子中的羥基與紫杉醇進(jìn)行偶聯(lián),而選擇2-51 是由于與其結(jié)構(gòu)最類似的化合物2-29 具有很好的活性,但分子中缺少可反應(yīng)的基團(tuán),因此在2-20 結(jié)構(gòu)中引入羥甲基獲得了化合物2-51(圖2).通過圖3 和圖4 的合成路線,2-18 和2-51 分別與紫杉醇偶聯(lián)制備了2-48 和2-53.
圖3 偶聯(lián)化合物2-48的合成路線Fig.3 Synthetic route of the conjugate 2-48
圖4 偶聯(lián)化合物2-53的合成路線Fig.4 Synthetic route of the conjugate 2-53
1.2.3 LTA4H 水解酶抑制活性實(shí)驗(yàn)
在化合物抑制 LTA4H 水解酶活性實(shí)驗(yàn)中以DMSO 作為陰性對(duì)照,Bestatin 為陽性對(duì)照,化合物濃度設(shè)置為 1μmol/L 和 10μmol/L.使用 LTB4ELISA kit,檢測(cè)LTA4H 作用于LTA4時(shí)LTB4的生成量.當(dāng)加入LTA4H 抑制劑后,抑制劑抑制酶活性,故可用LTB4生成減少的量評(píng)價(jià)抑制劑的抑制效果.以化合物組LTB4的生成量相對(duì)于DMSO 組LTB4生成量的百分比衡量化合物組對(duì)LTA4H 水解酶活的抑制效果,并計(jì)算出相應(yīng)的抑制率.
1.2.4 LTA4H 氨肽酶抑制活性實(shí)驗(yàn)
在LTA4H 的氨肽酶活性檢測(cè)時(shí)以DMSO 作為陰性對(duì)照,Bestatin 為陽性對(duì)照,化合物濃度設(shè)置為1μmol/L 和10μmol/L.使用L-丙氨酸-對(duì)硝基苯胺為底物,LTA4H 能使底物的C—N 鍵斷裂,生成丙氨酸和對(duì)硝基苯胺,在405 nm 下測(cè)定對(duì)硝基苯胺的吸光度.在一定范圍內(nèi),對(duì)硝基苯胺的生成量與酶濃度呈正比.當(dāng)加入LTA4H 抑制劑后,抑制劑抑制酶活性,LTA4H 降解底物的能力下降,用對(duì)硝基苯胺減少量評(píng)價(jià)抑制劑的抑制活力.
1.2.5 腫瘤細(xì)胞增殖抑制活性實(shí)驗(yàn)
采用MTT 法檢測(cè)合成的2 個(gè)偶聯(lián)化合物以及其分別的前體化合物、PTX 對(duì)HCT116(結(jié)腸癌細(xì)胞)和H460(肺癌細(xì)胞)兩種腫瘤細(xì)胞的增殖抑制活性.以正常細(xì)胞為對(duì)照,檢測(cè)在不同濃度化合物處理下腫瘤細(xì)胞的存活率,計(jì)算化合物抑制腫瘤細(xì)胞生長(zhǎng)的IC50值.
上述兩條合成路線制備的吲哚衍生物,經(jīng)HPLC檢測(cè)純度均達(dá)到95%以上,其結(jié)構(gòu)經(jīng)1H NMR、13C NMR 和HRMS 鑒定,均與預(yù)期結(jié)構(gòu)一致,其中終產(chǎn)物的結(jié)構(gòu)表征數(shù)據(jù)如下:
化合物 2-10 為無色油狀物,收率 69%.1H NMR(400 MHz,DMSO-d6)δ 2.18(s,6H),2.50(s,3H),2.61(t,J=6.8 Hz,2H),4.26(t,J=6.8 Hz,2H),6.41(d,J=2.8 Hz,1H),6.90(dd,J=8.8 Hz,1H),6.93~6.97(m,2H),7.28(d,J=2.4 Hz,1H),7.45(d,J =3.2 Hz,1H),7.54(d,J =8.8 Hz,1H),7.90~7.93(m,2H).13C NMR(100 MHz,DMSO-d6)δ 196.8,163.6,148.0,133.8,131.3,131.1,131.0,129.2,116.5,115.0,112.0,111.6,101.1,59.2,45.8,44.3,28.0.HRMS(ESI-TOF)m/z.C20H23N2O2+[M+H]+理論值323.175 4,實(shí)測(cè)值323.173 8.
化合物 2-11 為無色油狀物,收率 95%.1H NMR(400 MHz,DMSO-d6)δ 2.19(s,6H),2.60~2.63(m,5H),4.26(t,J=6.8 Hz,2H),6.39(d,J=2.8 Hz,1H),6.80(d,J=8 Hz,1H),6.94(dd,J=8.8 Hz,J=2.4 Hz,2H),7.12~7.16(m,1H),7.24(d,J=2.4 Hz,1H),7.43~7.48(m,2H),7.54(d,J=8.8 Hz,1H),7.70(dd,J=1.6 Hz,J=6 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 199.0,158.2,149.2,134.2,133.5,130.9,130.2,129.8,129.2,122.8,118.2,114.5,111.5,110.9,101.0,59.2,45.8,44.3,31.8.HRMS(ESI-TOF)m/z.C20H23N2O2+[M+H]+理論值323.175 4,實(shí)測(cè)值323.175 1.
化合物2-12 為無色油狀物,收率70%.1H NMR(400 MHz,DMSO-d6)δ 2.19(s,6H),2.62(t,J =6.8 Hz,2H),4.27(t,J=6.8 Hz,2H),6.42(d,J=2.8 Hz,1H),6.92(dd,J=8.4 Hz,J=2.0 Hz,1H),6.99~7.03(m,2H),7.31(d,J=2.4 Hz,1H),7.47(d,J=3.2 Hz,1H),7.55(d,J=16.8 Hz,1H),7.75~7.79(m,2H).13C NMR(100 MHz,DMSO-d6)δ 162.9,147.0,134.4,133.5,130.6,128.7,118.9,117.0,114.5,111.7,111.2,103.9,100.7,58.7,45.3,43.8.HRMS(ESI-TOF)m/z.C19H20N3O+[M+H]+理論值306.160 1,實(shí)測(cè)值306.159 7.
化合物 2-13 為無色油狀物,收率 33%.1H NMR(400 MHz,DMSO-d6)δ 2.19(s,6H),2.62(t,J=6.8 Hz,2H),4.27(t,J=6.8 Hz,2H),6.43(d,J=3.2 Hz,1H),6.78(d,J=8.8 Hz,1H),6.96(dd,J=2.4 Hz,J=8.8 Hz,2H),7.16~7.20(m,1H),7.33(d,J=2.4 Hz,1H),7.48(d,J=3.2 Hz,1H),7.54~7.58(m,2H),7.83~7.86(m,1H).13C NMR(100 MHz,DMSO-d6)δ 160.8,147.3,135.0,133.9,133.4,130.6,128.6,122.4,116.3,115.9,114.2,111.2,111.2,101.5,100.7,58.7,45.3,43.8.HRMS(ESI-TOF)m/z.C19H20N3O+[M+H]+理論值 306.160 1,實(shí)測(cè)值306.160 2.
化合物2-14 為無色油狀物,收率34%.1H NMR(400 MHz,DMSO-d6)δ 2.44(s,4H),2.67(t,J =6.8 Hz,2H),3.55(t,J =4.4 Hz,4H),4.31(t,J =6.8 Hz,2H),6.43(d,J=2.8 Hz,1H),6.92(dd,J=8.8 Hz,J=2.4 Hz,1H),7.01(d,J=8.8 Hz,2H),7.31(d,J=2.4 Hz,1H),7.49(d,J=2.8 Hz,1H),7.58(d,J=8.8 Hz,1H),7.77(d,J=8.8 Hz,2H).13C NMR(100 MHz,DMSO-d6)δ 163.3,147.5,134.9,133.9,131.1,129.2,119.4,117.5,115.0,112.2,111.8,104.4,101.2,66.7,58.3,53.8,43.5.HRMS(ESI-TOF)m/z.C21H22N3O2+[M+H]+理論值348.170 7,實(shí)測(cè)值348.169 0.
化合物2-15 為無色油狀物,收率75%.1H NMR(400 MHz,DMSO-d6)δ 1.64~1.68(m,4H),2.48~2.50(m,4H),2.80(t,J=6.8 Hz,2H),4.30(t,J=6.8 Hz,2H),6.43(d,J=2.8 Hz,1H),6.92(dd,J=8.8 Hz,J=2.4 Hz,1H),6.99~7.02(m,2H),7.31(d,J=2.0 Hz,1H),7.48(d,J=3.2 Hz,1H),7.56(d,J=8.8 Hz,1H),7.75~7.79(m,2H).13C NMR(100 MHz,DMSO-d6)δ 163.3,147.5,134.9,133.9,131.1,129.2,119.4,117.5,115.0,112.2,111.7,104.4,101.2,55.8,54.1,45.5,23.6.HRMS(ESI-TOF)m/z.C21H22N3O+[M+H]+理論值332.1757,實(shí)測(cè)值332.1740.
化合物2-16 為無色油狀物,收率46%.1H NMR(400 MHz,DMSO-d6)δ 1.65~1.67(m,4H),2.49~2.50(m,4H),2.80(t,J=6.8 Hz,2H),4.30(t,J=6.8 Hz,2H),6.43(d,J=2.8 Hz,1H),6.77(d,J=8.4 Hz,1H),6.96(dd,J=8.8 Hz,J=2.0 Hz,1H),7.16~7.20(m,1H),7.33(d,J=2.0 Hz,1H),7.49(d,J=3.2 Hz,1H),7.54~7.58(m,2H),7.85(dd,J=8.0 Hz,J=1.6 Hz,1H).13C NMR(100 MHz,DMSOd6)δ 161.3,147.8,135.6,134.4,133.9,131.1,129.2,123.0,116.8,116.4,114.7,111.8,111.7,102.0,101.2,55.8,54.1,45.5,23.6.HRMS(ESI-TOF)m/z.C21H22N3O+[M+H]+理論值 332.175 7,實(shí)測(cè)值332.174 9.
化合物2-17 為無色油狀物,收率50%.1H NMR(400 MHz,DMSO-d6)δ 2.43(s,4H),2.67(t,J =6.8 Hz,2H),3.54~3.56(m,4H),4.31(t,J=6.8 Hz,2H),6.44(d,J=2.8 Hz,1H),6.77(d,J=8.4 Hz,1H),6.97(dd,J=8.8 Hz,J=2.4 Hz,1H),7.19(t,J=7.6 Hz,1H),7.33(d,J=2.4 Hz,1H),7.49(d,J=2.8 Hz,1H),7.55~7.60(m,2H),7.85(dd,J =7.6 Hz,J=1.6 Hz,1H).13C NMR(100 MHz,DMSOd6)δ 161.6,147.9,134.1,133.7,133.7,129.7,129.1,121.8,116.5,115.8,115.2,112.3,110.4,102.5,101.5,67.0,58.2,53.9,53.5,44.3.HRMS(ESITOF)m/z.C21H22N3O2+[M+H]+理論值348.170 7,實(shí)測(cè)值348.170 0.
化合物2-18 為無色油狀物,收率92%.1H NMR(400 MHz,DMSO-d6)δ 1.30(d,J =6.4 Hz,3H),2.19(s,6H),2.60(t,J =6.8 Hz,2H),4.24(t,J =6.8 Hz,2H),4.68(m,1H),5.08(d,J=3.6 Hz,1H),6.37(d,J=2.8 Hz,1H),6.86(dd,J=8.8 Hz,3H),7.16(d,J=2.4 Hz,1H),7.28(d,J=8.4 Hz,2H),7.41(d,J =3.2 Hz,1H),7.48(d,J =8.8 Hz,1H).13C NMR(400 MHz,DMSO-d6)δ 157.9,149.8,141.6,133.2,130.6,129.1,127.2,117.2,114.7,111.3,110.8,100.8,68.1,59.2,45.8,44.3,26.4.HRMS(ESITOF)m/z.C20H25N2O2+[M+H]+理論值325.191 1,實(shí)測(cè)值325.191 0.
化合物2-19 為無色油狀物,收率57%.1H NMR(400 MHz,DMSO-d6)δ 1.36(d,J =6.0 Hz,3H),2.19(s,6H),2.61(t,J =6.8 Hz,2H),4.24(t,J =6.8 Hz,2H),5.12(m,1H),6.35(d,J=2.8 Hz,1H),6.66(dd,J=8.0 Hz,J=1.2 Hz,1H),6.84(dd,J=2.0 Hz,J=8.8 Hz,1H),7.05~7.08(m,2H),7.11~7.15(m,1H),7.39(d,J=2.8 Hz,1H),7.47(d,J=8.8 Hz,1H),7.58(dd,J=2.0 Hz,J=7.6 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 154.2,149.9,137.5,132.5,130.0,128.6,127.4,126.2,122.5,116.9,113.6,110.7,109.3,100.3,62.6,58.6,54.9.45.2,43.8,25.0.HRMS(ESI-TOF)m/z.C20H25N2O2+[M+H]+理論值325.191 1,實(shí)測(cè)值325.189 8.
化合物2-29 為無色油狀物,收率51%.1H NMR(400 MHz,DMSO-d6)δ 1.67~1.70(m,4H),2.55(d,J=5.2 Hz,4H),2.82(t,J=6.0 Hz,2H),4.05(d,J=6.0 Hz,2H),5.36(s,2H),6.39(d,J=2.8 Hz,1H),6.74(dd,J =2.4 Hz,J =8.8 Hz,1H),7.07(d,J =2.4 Hz,1H),7.16~7.18(m,2H),7.21~7.31(m,4H),7.44(d,J=3.2 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 153.1,138.8,131.5,130.0,129.2,128.9,127.7,127.4,112.2,111.3,103.7,101.1,67.5,55.0,54.5,49.7,23.6.HRMS(ESI-TOF)m/z.C21H25N2OH+[M+H]+理論值321.196 1,實(shí)測(cè)值321.194 7.
化合物2-30 為無色油狀物,收率29%.1H NMR(400 MHz,DMSO-d6)δ 1.67~1.70(m,4H),2.57(s,4H),2.83(t,J=6 Hz,2H),4.05(t,J=6 Hz,2H),5.38(s,2H),6.40(d,J=2.8 Hz,1H),6.75(dd,J=8.8 Hz,J=2.4 Hz,1H),7.07(d,J=2.4 Hz,1H),7.15(d,J=7.6 Hz,1H),7.25(t,J=8 Hz,1H),7.31(d,J=8.8 Hz,1H),7.35(s,1H),7.43(d,J=8 Hz,1H),7.46(d,J=3.2 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 153.1,141.7,131.4,131.1,130.6,130.0,130.0,129.2,126.4,122.2,112.3,111.2,103.8,101.3,67.4,54.9,54.4,48.9,23.5.HRMS(ESITOF)m/z.C21H24N2OBr+[M+H]+理論值399.106 7,實(shí)測(cè)值399.107 3.
化合物2-31 為無色油狀物,收率64%.1H NMR(400 MHz,CDCl3)δ 1.87(s,4H),2.73(s,4H),3.00(t,J=5.6 Hz,2H),4.22(t,J=5.6 Hz,2H),5.21(s,2H),6.52(s,1H),6.91~6.95(m,2H),7.10~7.14(m,3H),7.19~7.26(m,3H).13C NMR(100 MHz,DMSO-d6)δ 153.2,141.5,133.6,131.5,130.9,130.1,129.3,127.7,127.1,126.1,112.3,111.2,103.8,101.4,67.5,54.9,54.5,49.0,23.6.HRMS(ESITOF)m/z.C21H24N2OCl+[M+H]+理論值355.157 2,實(shí)測(cè)值355.155 5.
化合物2-32 為無色油狀物,收率71%.1H NMR(400 MHz,DMSO-d6)δ 1.67~1.70(m,4H),2.54(s,4H),2.80(t,J=6 Hz,2H),3.68(s,3H),4.04(t,J=6 Hz,2H),5.33(s,2H),6.38(d,J=3.2 Hz,1H),6.70~6.75(m,3H),6.80(dd,J=8.8 Hz,J=2.4 Hz,1H),7.07(d,J=2.4 Hz,1H),7.20(t,J=8 Hz,1H),7.30(d,J =9.2 Hz,1H),7.43(d,J =3.2 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 159.8,153.1,140.5,131.6,130.08,130.06,129.2,119.5,113.4,112.8,112.2,111.3,103.7,101.1,67.5,55.4,55.0,54.5,49.6,23.6.HRMS(ESI-TOF)m/z.C22H27N2O2+[M+H]+理論值351.206 7,實(shí)測(cè)值351.208 4.
化合物2-33 為無色油狀物,收率90%.1H NMR(400 MHz,DMSO-d6)δ 1.39(d,J =5.2 Hz,2H),1.49~1.54(m,4H),2.50(d,J=1.6 Hz,4H),2.71(s,2H),4.05(t,J=6 Hz,2H),5.36(s,2H),6.38(d,J=3.2 Hz,1H),6.73(dd,J=2.4 Hz,J=8.8 Hz,1H),7.07(d,J =2 Hz,1H),7.16(d,J =7.2 Hz,2H),7.21~7.24(m,1H),7.29(m,3H),7.44(d,J =2.8 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 153.1,138.9 131.5,130.1,129.2,128.9,127.7,127.4,112.2,112.3,103.8,101.1,66.3,57.9,54.8,49.7,25.8,24.2.HRMS(ESI-TOF)m/z.C22H27N2O+[M+H]+理論值357.193 7,實(shí)測(cè)值357.194 0.
化合物2-34 為無色油狀物,收率34%.1H NMR(400 MHz,DMSO-d6)δ 1.38(t,J =5.2 Hz,2H),1.47~1.53(m,4H),2.46(s,4H),2.68(t,J=5.2 Hz,2H),4.04(t,J=6 Hz,2H),5.38(s,2H),6.39(d,J=3.2 Hz,1H),6.75(dd,J=2.4 Hz,J=8.8 Hz,1H),7.07(d,J =2 Hz,1H),7.15(d,J =7.6 Hz,1H),7.25(t,J=7.6 Hz,1H),7.31(d,J=8.8 Hz,1H),7.36(s,1H),7.43(d,J=7.6 Hz,1H),7.46(d,J=3.2 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 153.2,141.8,131.4,131.2,130.6,130.04,130.02,129.2,126.4,122.3,112.3,112.2,103.8,101.4,66.4,58.0,54.8,48.9,25.9,24.3.HRMS(ESI-TOF)m/z.C21H26N2OBr+[M+H]+理論值 413.122 3,實(shí)測(cè)值413.120 7.
化合物2-35 為無色油狀物,收率57%.1H NMR(400 MHz,DMSO-d6)δ 1.34~1.40(m,2H),1.47~1.52(m,4H),2.45(s,4H),2.67(t,J=5.6 Hz,2H),4.04(t,J=5.6 Hz,2H),5.38(s,2H),6.39(d,J=2.8 Hz,1H),6.74(dd,J=2.4 Hz,J=8.8 Hz,1H),7.07(d,J=2.4 Hz,1H),7.11(d,J=6.8 Hz,2H),7.20(s,1H),7.28~7.34(m,3H),7.46(d,J=3.2 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 153.2,141.5,133.6,131.4,130.9,130.1,129.2,127.7,127.1,126.1,112.4,112.2,103.8,101.4,66.4,58.0,54.9,49.0,26.0,24.4.HRMS(ESI-TOF)m/z.C22H26N2OCl+[M+H]+理論值369.172 8,實(shí)測(cè)值369.171 3.
化合物2-36 為無色油狀物,收率13%.1H NMR(400 MHz,DMSO-d6)δ 1.53(s,2H),1.74(s,4H),2.50(t,J =1.6 Hz,2H),3.45(d,J =4 Hz,4H),3.68(s,3H),4.30(t,J=5.2 Hz,2H),5.35(s,2H),6.41(d,J=2.8 Hz,1H),6.71(d,J=7.6 Hz,1H),6.74(s,1H),6.79~6.83(m,2H),7.16(d,J=2.4 Hz,1H),7.20(t,J=8 Hz,1H),7.36(d,J=8.8 Hz,1H),7.49(d,J=3.2 Hz,1H).13C NMR(100 MHz,CDCl3)δ 159.7,151.5,138.9,131.9,1 297,129.3,128.9,118.8,112.5,112.5,111.8,110.6,104.1,101.2,62.9,56.1,55.1,53.7,50.1,29.5,22.5,21.4.HRMS(ESITOF)m/z.C23H29N2O2+[M+H]+理論值365.222 4,實(shí)測(cè)值365.220 6.
化合物2-37 為無色油狀物,收率36%.1H NMR(400 MHz,CDCl3)δ 2.91(t,J=5.6 Hz,2H),3.02(t,J=6.4 Hz,2H),3.27(t,J=6.4 Hz,2H),4.24(t,J=5.6 Hz,2H),4.28(s,2H),5.36(s,2H),6.57(d,J=2.8 Hz,1H),6.96(dd,J =2 Hz,J =8.8 Hz,1H),7.18~7.24(m,5H),7.33~7.40(m,3H).13C NMR(100 MHz,CDCl3)δ 153.2,137.6,131.9,129.1,129.0,128.8,127.6,126.78,112.7,110.5,104.0,101.3,68.2,61.3,58.7,52.4,50.3,29.7.HRMS(ESITOF)m/z.C20H23N2OS+[M+H]+理論值339.152 6,實(shí)測(cè)值339.151 1.
化合物2-38 為無色油狀物,收率80%.1H NMR(400 MHz,DMSO-d6)δ 2.68(t,J =5.6 Hz,2H),2.81(t,J =6.4 Hz,2H),3.07(t,J =6.4 Hz,2H),4.07(t,J=5.6 Hz,2H),4.11(s,2H),5.38(s,2H),6.40(d,J =2.8 Hz,1H),6.76(dd,J =8.8 Hz,J =2.0 Hz,1H),7.08(d,J=2.0 Hz,1H),7.15(d,J=8.0 Hz,1H),7.26(t,J=8.0 Hz,1H),7.32(d,J=9.2 Hz,1H),7.35(s,1H),7.43(d,J=8.0 Hz,1H),7.47(d,J=2.8 Hz,1H).13C NMR(100 MHz,DMSOd6)δ 153.1,141.7,131.4,131.1,130.6,130.03,129.99,129.2,126.4,122.2,112.3,112.2,103.8,101.3,68.0,61.4,58.6,51.9,48.9,29.3.HRMS(ESITOF)m/z.C20H22N2OSBr+[M+H]+理論值439.045 0,實(shí)測(cè)值439.042 9.
化合物2-39 為無色油狀物,收率65%.1H NMR(400 MHz,DMSO-d6)δ 2.68(t,J =5.6 Hz,2H),2.81(t,J =6.4 Hz,2H),3.07(t,J =6.4 Hz,2H),4.07(t,J=5.6 Hz,2H),4.11(s,2H),5.39(s,2H),6.40(d,J =2.8 Hz,1H),6.76(dd,J =2.4 Hz,J =8.8 Hz,1H),7.08(d,J=2.4 Hz,1H),7.11(d,J=6.8 Hz,1H),7.20(s,1H),7.31(t,J=2 Hz,1H),7.33(d,J =2 Hz,1H),7.47(d,J =3.2 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 153.2,141.5,133.6,131.5,130.9,130.1,129.2,127.7,127.1,126.1,112.3,112.2,103.8,101.4,68.0,61.4,58.6,52.4,51.9,49.0,29.4.HRMS(ESI-TOF)m/z.C20H22N2OSCl+[M+H]+理論值373.113 6,實(shí)測(cè)值373.112 4.
化合物2-40 為無色油狀物,收率76%.1H NMR(400 MHz,DMSO-d6)δ 2.68(t,J =5.6 Hz,2H),2.81(t,J =6.4 Hz,2H),3.07(t,J =6.4 Hz,2H),3.68(s,3H),4.06(t,J=5.6 Hz,2H),4.11(s,2H),5.33(s,2H),6.38(d,J=2.8 Hz,1H),6.71(d,J=7.6 Hz,1H),6.74~6.76(m,2H),6.80(dd,J =2.4 Hz,J =8.8 Hz,1H),7.07(d,J =2 Hz,1H),7.20(t,J =8 Hz,1H),7.31(d,J =8.8 Hz,1H),7.44(d,J=2.8 Hz,1H).13C NMR(100 MHz,CDCl3)δ 160.0,153.2,139.3,131.9,129.8,129.1,129.0,119.1,112.8,110.5,104.0,101.3,68.2,61.2,58.6,55.2,52.4,50.2,29.6.HRMS(ESI-TOF)m/z.C21H25N2O2S+[M+H]+理論值 369.163 1,實(shí)測(cè)值369.162 9.
化合物2-41 為無色油狀物,收率64%.1H NMR(400 MHz,DMSO-d6)δ 2.47(t,J =4.4 Hz,4H),2.68(t,J =6.0 Hz,2H),3.57(t,J =4.8 Hz,4H),4.05(d,J=6.0 Hz,2H),5.36(s,2H),6.38(d,J=2.4 Hz,1H),,6.74(dd,J=2Hz,J=8.8 Hz,1H),7.07(d,J=2.4 Hz,1H),7.16(d,J=6.8 Hz,2H),7.22~7.24(m,1H),7.27~7.31(m,3H),7.44(d,J=3.2 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 153.1,138.9,131.5,131,129.2,128.9,127.7,127.4,112.2,111.3,103.8,101.1,66.7,66.3,57.7,54.1,49.7.HRMS(ESI-TOF)m/z.C21H25N2O2+[M+H]+理論值337.191 1,實(shí)測(cè)值337.189 5.
化合物2-42 為無色油狀物,收率73%.1H NMR(400 MHz,DMSO-d6)δ 2.47(t,J=4.0 Hz,4H)2.68(t,J=6.0 Hz,2H),3.58(t,J=4.4 Hz,4H),4.06(d,J=6.0 Hz,2H),5.38(s,2H),6.40(d,J=3.2 Hz,1H),6.75(dd,J=2.4 Hz,J=8.8 Hz,1H),7.08(d,J=2 Hz,1H),7.15(d,J=8.0 Hz,1H),7.25(t,J=8.0 Hz,1H),7.31(d,J=8.8 Hz,1H),7.36(s,1H),7.43(d,J =8.0 Hz,1H),7.46(d,J =2.8 Hz,1H).13C NMR(100 MHz,CDCl3)δ 153.3,140.0,131.6,130.7,130.3,129.6,129.1,128.7,125.2,122.8,112.7,110.3,103.0,101.6,66.9,66.5,57.8,54.1,49.6.HRMS(ESI-TOF)m/z.C21H24N2O2Br+[M+H]+理論值415.101 6,實(shí)測(cè)值415.100 5.
化合物2-43 為無色油狀物,收率82%.1H NMR(400 MHz,DMSO-d6)δ 2.47(s,4H),2.68(t,J=6.0 Hz,2H),3.57(t,J=4.4 Hz,4H),4.06(d,J=6.0 Hz,2H),5.38(s,2H),6.40(d,J=2.8 Hz,1H),6.75(dd,J=2.4 Hz,J=8.8 Hz,1H),7.08(d,J=2 Hz,1H),7.11(d,J=6.8 Hz,1H),7.20(s,1H),7.29(d,J=8 Hz,1H),7.33(d,J=6.8 Hz,1H),7.46(d,J=2.8 Hz,1H).13C NMR(100 MHz,DMSOd6)δ 153.2,141.5,133.6,131.5,130.9,130.1,129.2,127.7,127.1,126.0,112.4,111.2,103.9,101.4,66.7,66.3,57.7,54.1,49.0.HRMS(ESI-TOF)m/z.C21H24N2O2Cl+[M+H]+理論值 371.152 1,實(shí)測(cè)值371.1505.
化合物2-44 為無色油狀物,收率54%.1H NMR(400 MHz,DMSO-d6)δ 2.47(t,J =4.4 Hz,4H),2.68(t,J =6.0 Hz,2H),3.58(t,J =4.4 Hz,4H),3.68(s,3H),4.05(t,J=6.0 Hz,2H),5.32(s,2H),6.38(d,J=3.2 Hz,1H),6.71(d,J=7.6 Hz,1H),6.73~6.75(m,2H),6.80(dd,J=2.4 Hz,J=8.0 Hz,1H),7.07(d,J=2.4 Hz,1H),7.20(t,J=8.0 Hz,1H),7.30(d,J=8.8 Hz,1H),7.43(d,J=2.8 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 159.8,153.1,140.5,131.6,130.1,130.1,129.2,119.5,113.4,112.8,112.2,111.3,103.8,101.1,66.7,66.3,57.7,55.4,54.2,49.6.HRMS(ESI-TOF)m/z.C22H27N2O3+[M+H]+理論值367.197 7,實(shí)測(cè)值367.201 2.
化合物2-45 為無色油狀物,收率34%.1H NMR(400 MHz,DMSO-d6)δ 1.71(t,J =3.6 Hz,4H),2.62(s,4H),2.88(t,J =6.0,Hz,2H),4.07(t,J =6.0 Hz,2H),5.42(s,2H),6.43(d,J=3.2 Hz,1H),6.51~6.53(m,1H),6.76(dd,J=2.4 Hz,J=8.8 Hz,1H),7.11(d,J=2.0 Hz,1H),7.20~7.23(m,2H),7.39(d,J =3.2 Hz,1H),7.65~7.67(m,1H).13C NMR(100 MHz,DMSO-d6)δ 153.2,137.6,133.1,131.6,13.2,129.8,129.7,128.6,128.5,122.2,112.4,111.1,103.9,101.5,67.3,54.9,54.5,49.9,23.5.HRMS(ESI-TOF)m/z.C21H24N2OBr+[M+H]+理論值399.106 7,實(shí)測(cè)值399.106 1.
化合物 2-46 為無色油狀物,收率 46%.1H NMR(400 MHz,DMSO-d6)δ 1.68(s,4H),2.62(s,4H),2.81(t,J=6.0 Hz,2H),4.04(t,J=6.0 Hz,2H),5.34(s,2H),6.39(d,J=2.8 Hz,1H),6.74(dd,J=2.0 Hz,J=8.8 Hz,1H),7.07(d,J=2.0 Hz,1H),7.10(d,J=8.4 Hz,1H),7.28(d,J=8.8 Hz,2H),7.43(d,J=3.2 Hz,1H),7.48(d,J=8.0 Hz,2H).13C NMR(100 MHz,DMSO-d6)δ 153.2,138.3,131.8,131.4,130.0,129.6,129.3,120.8,112.3,111.2,103.8,101.3,67.5,54.9,54.5,49.0,23.6.HRMS(ESITOF)m/z.C21H24N2OBr+[M+H]+理論值399.106 7,實(shí)測(cè)值399.106 0.
化合物2-51 為無色油狀物,收率41%.1H NMR(400 MHz,DMSO-d6)δ 1.50~1.56(m,1H),1.58~1.68(m,2H),1.75~1.84(m,1H),2.30(dd,J =8.8 Hz,J=16.4 Hz,1H),2.53~2.55(m,1H),2.65~2.71(m,1H),3.09~3.19(m,2H),3.22~3.27(m,1H),3.39~3.42(m,1H),4.02(t,J=6.0 Hz,2H),4.37(s,1H),5.36(s,2H),6.38(d,J=2.8 Hz,1H),6.73(dd,J =2.0 Hz,J =8.8 Hz,1H),7.06(d,J =2.0 Hz,1H),7.17(d,J=7.2 Hz,2H),7.21~7.24(m,1H),7.27~7.31(m,3H),7.43(d,J=3.2 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 153.1,138.9,131.5,130.0,129.2,129.0,127.7,127.4,112.2,111.3,103.8,101.1,68.0,65.9,64.8,55.2,54.3,28.3,23.4.HRMS(ESI-TOF)m/z.C22H27N2O2+[M+H]+理論值351.202 8,實(shí)測(cè)值351.206 2.
對(duì)兩類吲哚衍生物分別進(jìn)行了LTA4H 氨肽酶抑制活性測(cè)試,結(jié)果見表1 和表2.
從表1 可以看出:在兩個(gè)濃度下,化合物2-10、2-12、2-15、2-18 氨肽酶抑制活性與Bestatin 相當(dāng)甚至更優(yōu),分析其結(jié)構(gòu)發(fā)現(xiàn)吲哚1 位的親水基團(tuán)為四氫吡咯環(huán)或N,N-二甲胺基時(shí),吲哚5 位疏水端的苯環(huán)有對(duì)位取代基團(tuán),尤其是氰基、羥乙基時(shí)氨肽酶抑制活性較好.
表1 第一類化合物L(fēng)TA4H 氨肽酶抑制活性Tab.1 The LTA4H aminopeptidase inhibitory activity of the first type compound
表2 第二類化合物L(fēng)TA4H 氨肽酶抑制活性Tab.2 The LTA4H aminopeptidase inhibitory activity of the second type compound
從表 2 可以看出:大部分化合物都具有和Bestatin 類似的活性,在1μmol/L 濃度下,化合物2-29、2-33、2-37、2-41、2-44、2-46 的抑制率均高于Bestatin,在10μmol/L 濃度下,化合物2-29、2-33、2-46 抑制率高于Bestatin.結(jié)構(gòu)分析發(fā)現(xiàn):當(dāng)吲哚5 位的親水基團(tuán)為吡咯烷或哌啶環(huán),吲哚1 位的苯環(huán)上無取代或間位甲氧基取代、對(duì)位溴取代時(shí),化合物對(duì)LTA4H 氨肽酶抑制活性較好.
對(duì)于抗腫瘤作用來說,LTA4H 的氨肽酶活性和水解酶活性是一致的,即兩種活性的抑制效果越好,其對(duì)抗腫瘤的預(yù)期效果也越好.因此,選取部分氨肽酶抑制活性較好的化合物進(jìn)行LTA4H 水解酶抑制活性測(cè)試,結(jié)果見表3.
表3 化合物L(fēng)TA4H水解酶抑制活性Tab.3 The LTA4H hydrolase inhibitory activity of the compound
從表3 可看出:所選化合物也同樣具備LTA4H水解酶抑制活性,尤其是10μmol/L 下活性基本與Bestatin 相似或稍差,而化合物2-10、2-12、2-29、2-33在低濃度下也有較好的水解酶抑制活性.
在與紫杉醇偶聯(lián)形成孿藥時(shí),選擇了LTA4H 氨肽酶抑制活性和水解酶抑制活性均較好且結(jié)構(gòu)中有合適官能團(tuán)進(jìn)行連接的兩個(gè)吲哚衍生物(2-18 和2-51),通過丁二?;c紫杉醇側(cè)鏈羥基相偶聯(lián),制備得到兩個(gè)偶聯(lián)物,分別為2-48 和2-53,結(jié)構(gòu)表征如下:
化合物2-48 為白色固體,收率88%.1H NMR(400 MHz,DMSO-d6)δ 1.00(s,3H),1.03(s,3H),1.08~1.14(m,1H),1.23~1.27(m,3H),1.50(s,3H),1.77(d,J=5.2 Hz,2H),2.09(s,3H),2.21~2.23(m,9H),2.29~2.33(m,1H),2.59~2.66(m,6H),3.58~3.59(m,1H),3.98~4.04(m,2H),4.10~4.12(m,1H),4.24~4.28(m,2H),4.63(d,J =4.0 Hz,1H),4.85~4.92(m,2H),5.34~5.37(m,1H),5.42(d,J=5.6 Hz,1H),5.52~5.58(m,1H),5.69~5.74(m,1H),5.80~5.86(m,1H),6.30(s,1H),6.38(d,J=1.6 Hz,1H),6.89(dd,J=1.6 Hz,J=8.8 Hz,3H),7.18~7.20(m,2H),7.26~7.29(m,2H),7.42~7.55(m,9H),7.64~7.67(m,2H),7.71~7.73(m,1H),7.84~7.87(m,2H),7.98(d,J =8.0 Hz,2H),9.22(dd,J=3.2 Hz,J=8.4 Hz,1H).13C NMR(100 MHz,DMSO-d6)δ 202.9,172.0,171.3,170.1,169.5,169.5,169.3,167.0,166.9,165.7,159.1,158.9,157.3,149.4,149.3,140.0,137.8,135.6,135.4,134.8,134.7,134.0,133.9,133.39,133.36,132.0,130.7,130.5,130.1,129.2,128.8,128.7,128.1,128.1,128.0,127.9,117.3,117.2,115.0,114.9,111.4,111.3,111.2,101.1,84.1,80.8,77.2,75.8,75.2,75.0,72.2,71.3,70.9,58.9,58.0,57.9,55.4,54.5,46.6,45.6,44.1,43.5,41.2,26.8,23.8,23.0,22.5,22.3,21.9,21.1,14.4,10.3.HRMS(ESI-TOF)m/z.C71H78N3O18+[M+H]+理論值1 260.527 5,實(shí)測(cè)值1 260.526 3.
化合物2-53 為白色固體,收率51%.1H NMR(400 MHz,DMSO-d6)δ 1.00(s,3H),1.02(s,3H),1.09~1.15(m,1H),1.23~1.27(m,1H),1.50(s,4H),1.61~1.67(m,3H),1.77(s,3H),1.80~1.84(m,1H),2.08(s,3H),2.23(s,3H),2.31~2.33(m,2H),2.54~2.57(m,2H),2.62~2.64(m,2H),2.71(s,2H),3.08(s,2H),3.58(d,J=6.4 Hz,1H),3.75~3.82(m,1H),3.94~3.95(m,1H),3.98~4.04(m,1H),4.63(s,1H),4.89~4.91(m,2H),5.34~5.36(m,3H),5.42(d,J=7.2 Hz,1H),5.55(t,J=8.8 Hz,1H),5.84(t,J =8.8 Hz,1H),6.30(s,1H),6.37(s,1H),6.72(d,J=8.4 Hz,1H),7.05(s,1H),7.15~7.20(m,3H),7.22~7.24(m,1H),7.26~7.30(m,3H),7.44~7.50(m,7H),7.53~7.55(m,1H),7.64~7.68(m,2H),7.71~7.75(m,1H),7.86(d,J=7.2 Hz,2H),7.98(d,J=7.2 Hz,2H),9.23(d,J=8.0 Hz,1H).13C NMR(100 MHz,DMSOd6)δ 202.9,171.9,170.1,169.5,169.2,166.9,165.7,139.9,138.9,137.8,134.7,134.0,133.9,132.0,131.5,130.4,130.1,129.2,129.0,128.8,128.7,128.1,127.9,127.7,127.4,112.2,111.3,103.8,101.1,84.1,80.7,77.2,75.8,75.2,75.0,71.2,70.9,67.9,67.3,57.9,55.4,54.9,54.4,54.1,49.7,46.5,43.4,28.9,28.3,26.8,23.8,23.5,23.0,21.9,21.1,14.4,10.3.HRMS(ESI-TOF)m/z.C73H80N3O18+[M+H]+理論值1 286.539 2,實(shí)測(cè)值1 286.543 7.
體外評(píng)價(jià)2 個(gè)偶聯(lián)物及其前體化合物對(duì)兩種腫瘤細(xì)胞增殖的抑制活性,結(jié)果見表4.偶聯(lián)前化合物2-18 和2-51 對(duì)HCT116 細(xì)胞均顯示一定抑制活性.化合物2-18 對(duì)H460 細(xì)胞未表現(xiàn)出明顯活性,而化合物2-51 則有一定的抑制活性,兩個(gè)吲哚衍生物分別與紫杉醇偶聯(lián)后所得到的化合物2-48 和2-53有同樣的趨勢(shì),即對(duì)HCT116 細(xì)胞的抑制作用更強(qiáng).對(duì)結(jié)腸癌細(xì)胞HCT116 的這種選擇性可能與已報(bào)道的LTA4H 在結(jié)腸癌細(xì)胞中的高表達(dá)有關(guān),因?yàn)榻Y(jié)直腸癌通常是由長(zhǎng)期的慢性炎癥和潰瘍導(dǎo)致,因此本文所設(shè)計(jì)合成的吲哚衍生物以及與紫杉醇的偶聯(lián)物對(duì)與炎癥高度相關(guān)的腫瘤具有重要的研究?jī)r(jià)值.
表4 化合物抑制腫瘤增殖活性Tab.4 The antitumor activity of compounds
根據(jù)LTA4H 抑制劑的研究進(jìn)展以及炎癥與癌癥的聯(lián)系,結(jié)合DG-051 的結(jié)構(gòu)和LTA4H 的晶體結(jié)構(gòu),設(shè)計(jì)合成兩類共計(jì)30 個(gè)1,5-二取代吲哚衍生物,均為全新化合物.LTA4H 抑制活性測(cè)試結(jié)果表明,大部分化合物都顯示出較好的LTA4H 抑制活性,其中化合物2-12、2-15、2-18、2-29 和2-33 抑制活性尤為顯著.初步構(gòu)效分析發(fā)現(xiàn):以吲哚為母核結(jié)構(gòu),吲哚環(huán)的1 位選擇N,N-二甲胺基作為親水基團(tuán),5 位選擇苯環(huán)、對(duì)位羥乙基或氰基取代的苯環(huán)作為疏水基團(tuán)時(shí),或者5 位選擇四氫吡咯環(huán)、哌啶環(huán)作為親水基團(tuán),1 位選擇苯環(huán)取代時(shí),對(duì)LTA4H 的抑制活性更高.為了探索該類化合物在抗腫瘤領(lǐng)域的應(yīng)用,選取LTA4H 抑制活性較好的2 個(gè)化合物與PTX 共價(jià)偶聯(lián)并進(jìn)行體外抗腫瘤活性測(cè)試,偶聯(lián)化合物2-48 和2-53 表現(xiàn)出對(duì)結(jié)腸癌細(xì)胞HCT116 較好的抑制效果,與預(yù)期一致.