吳春雷 豐誠杰 莊大衛(wèi) 羅蒙強 李金龍
(紹興文理學(xué)院 化學(xué)化工學(xué)院,浙江 紹興312000)
雜環(huán)化合物在藥物發(fā)現(xiàn)過程中有著重要的作用.吲哚環(huán)經(jīng)常出現(xiàn)在許多重要的天然產(chǎn)物、藥物及其他具有各種生物活性化合物中[1-2].螺環(huán)結(jié)構(gòu)也經(jīng)常出現(xiàn)在一些具有重要活性作用的天然產(chǎn)物中[3].而在吲哚酮的3 號位上引入各類雜環(huán)形成的螺環(huán)吲哚酮類化合物,由于其獨特的藥理活性而成為目前藥物化學(xué)界研究的一個熱點[4-6],例如,Wang 等人報道了螺環(huán)吲哚-3,3’-吡啶類化合物有潛在的MDM2 受體抑制活性[7].而據(jù)報道氧雜蒽類物質(zhì)具有抗病毒、抗菌和抗炎等藥理活性,并且在光動力療法(PDT)中也被稱為消除腫瘤細(xì)胞的敏化劑[8-11].而螺[吲哚-3,9'-氧雜蒽]三酮結(jié)合了螺環(huán)、吲哚及氧雜蒽的結(jié)構(gòu)特點,自Laurac 于1959 年首次報道以來,引起了研究人員對其獨特結(jié)構(gòu)和生物學(xué)效應(yīng)的關(guān)注[12].各種催化劑也被應(yīng)用于此類物質(zhì)的合成,如p-TSA[13-14],ZnO[15],ZnFe2O4[16],B(HSO4)3[17],二氧化硅納米粒子負(fù)載的HBF4[18]和SnCl4[19]等.盡管這些催化劑都有各自的特點,但仍有待開發(fā)一種新穎而有效的方法來合成螺[吲哚-3,9'-氧雜蒽]三酮類化合物.
近年來,三氟甲磺酸鹽作為一種遇水穩(wěn)定、可回收的新型Lewis 酸催化劑,在有機合成中得到了廣泛的應(yīng)用[20-24].為了進一步研究螺環(huán)化合物的合成和三氟甲磺酸鹽的應(yīng)用,我們研究了Lewis 酸三氟甲磺酸銅催化下,靛紅與1,3-環(huán)己二酮縮合反應(yīng)制備螺[吲哚-3,9'-氧雜蒽]三酮類化合物(見圖1).
所有試劑均為市售,無需進一步純化即可使用.IR 在Nicolet-6700 光譜儀上測得;NMR 在Bruker AVANCE DMX III400 M 上測定;元素分析在Euro vector EA 3000 CHN 分析儀上測得;熔點在BUCHI M-560 熔點儀測得.
圖1 螺[吲哚-3,9'-氧雜蒽]三酮的合成
將Cu(OTf)2(0.2 mmol)加入到靛紅(2 mmol)和雙甲酮(4 mmol)的乙醇溶液中,并將所得的混合物在80℃下攪拌10 ~12 h.反應(yīng)完成后(TLC,乙酸乙酯/石油醚=1:4),將混合物冷卻至室溫.將所得固體過濾,并依次用水(2×30 mL)和冷乙醇水溶液(2×1 mL)洗滌,得到粗產(chǎn)物,再將其用乙醇重結(jié)晶,得到純產(chǎn)物.重結(jié)晶時,會觀察到微量的不溶性雜質(zhì),需趁熱過濾除去.所得產(chǎn)物表征如下:
3',3',6',6'-四甲基-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3 a).白色粉末;M.p.:306-307 ℃(Lit.[14]305 ℃);IR(KBr)cm-1:3431,2957,1733,1666,1616,1469,1345,1222,1168.1H NMR(400 MHz,CDCl3):δH(ppm)1.04(6 H,s,2 CH3),1.12(6 H,s,2 CH3),2.11and2.25(4 H,AB system,J=16 Hz,2 CH2),2.44and2.56(4 H,J=17.6 Hz,2 CH2),6.83-6.90(3 H,m,H-Ar),7.13-7.17(1 H,m,HAr),7.62(1 H,s,NH);13C NMR(100 MHz,CDCl3):δC(ppm)27.2,29.0,32.0,41.2,45.7,50.9,109.4,113.6,121.9,122.3,128.5,133.6,142.3,163.5,178.8,195.3;Anal.Calcd for C24H25NO4:C,73.64;H,6.44;N,3.58%. Found:C,73.67;H,6.36;N,3.52%.
5,3',3',6',6'-五甲基-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3 b).白色粉末;M.p.:294-295 ℃(Lit.[15]310 ℃);IR(KBr)cm-1:3314,2959,1745,1670,1618,1349,1315,1168.1H NMR(CDCl3):δH(ppm)1.04(6 H,s,2 CH3),1.12(6 H,s,2 CH3),2.13and2.24(4 H,AB system,J=16.4 Hz,2 CH2),2.21(3 H,s,CH3),2.45and2.55(4 H,AB system,J=17.6 Hz,2CH2),6.66(1 H,s,H-Ar),6.73(1 H,d,J=8.0 Hz,H-Ar),6.95(1 H,d,J=7.6 Hz,H-Ar),7.46(1 H,s,NH).13C NMR(CDCl3):δC(ppm)21.2,27.4,28.9,31.9,41.2,45.7,50.9,108.9,113.7,123.2,128.9,132.2,133.7,139.8,163.4,178.7,195.3. Anal.Calcd for C25H27NO4:C,74.05;H,6.71;N,3.45%.Found:C,73.58;H,6.41;N,3.48%.
3',3',6',6'-四甲基-5-氯-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3c).白色粉末;M.p.:308-309 ℃(Lit.[25]309-310 ℃);IR(KBr)cm-1:3457,2958,1739,1665,1616,1509,1349,1224,1120.1H NMR(CDCl3):δH(ppm)1.06(6 H,s,2 CH3),1.12(6 H,s,2 CH3),2.16and2.26(4 H,ABsystem,J=16.4 Hz,2 CH2),2.48and2.56(4 H,J=17.6 Hz,2 CH2),6.76(1 H,d,J=8.4 Hz,H-Ar),6.83(1 H,d,J=1.6 Hz,H-Ar),7.12(1 H,dd,J=1.6 Hz,J=8.4 Hz,H-Ar),7.89(1 H,s,NH).13CNMR(CDCl3):δC(ppm)27.5,28.7,31.9,41.2,45.8,50.9,110.3,113.2,122.6,126.9,128.3,135.2,141.2,163.8,178.3,195.4.Anal.Calcd for C24H24ClNO4:C,67.68;H,5.68;N,3.29%.Found:C,67.59;H,5.62;N,3.37%.HRMS(ESI):m/z[M+H]+calcd for C24H24ClNO4:425.9047;found:425.9041.
3',3',6',6'-四甲基-5-硝基-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3d).淺黃色粉末;M.p.:276-277 ℃(Lit.[14]278 ℃);IR (KBr)cm-1:3452,2958,1745,1667,1629,1346,1225,1169.1H NMR(CDCl3):δH(ppm)1.00(6 H,s,2 CH3),1.11(6 H,s,2 CH3),2.17and2.26(4 H,AB system,J=16 Hz,2 CH2),2.53and2.59(4 H,AB system,J=18 Hz,2 CH2),6.89(1 H,d,J=8.8 Hz,H-Ar),7.80(1 H,d,J=2.0 Hz,H-Ar),8.14(1 H,dd,J=2.0 Hz,J=8.8 Hz,H-Ar),8.37(1 H,s,NH).13C NMR(CDCl3):δC(ppm)27.7,28.5,32.1,41.1,45.5,50.8,108.9,112.8,118.1,125.9,134.5,143.0,148.6,164.5,178.6,195.8.Anal.Calcd for C24H24N2O6:C,66.04;H,5.54;N,6.42%.Found:C,65.91;H,5.47;N,6.29%.
7,3',3',6',6'-五甲基-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3 e).白色粉末;M.p.:288 ℃(Lit.[25]287-289 ℃);IR(KBr)cm-1:3336,2955,1731,1671,1618,1348,1224,1168.1H NMR(CDCl3):δH(ppm)1.04(6 H,s,2CH3),1.12(6 H,s,2 CH3),2.15and2.25(4 H,AB system,J = 17.2 Hz,2CH2),2.27(3 H,s,CH3),2.45and2.56(4 H,AB system,J=17.6 Hz,2 CH2),6.70(1 H,d,J=7.2 Hz,H-Ar),6.80 (1 H,J=7.2 Hz,J=7.6 Hz,H-Ar),6.97(1H,d,J=7.6 Hz,H-Ar),7.48(1 H,s,NH).13C NMR(CDCl3):δC(ppm)16.3,27.1,29.0,33.6,41.2,54.8,111.9,113.7,118.0,120.0,121.9,140.8,163.4,168.7,179.0,181.6,195.4,202.3.Anal.Calcd for C25H27NO4:C,74.05;H,6.71;N,3.45%. Found:C,73.53;H,6.53;N,3.37%.HRMS(ESI):m/z[M+H]+calcd for C25H27NO4:405.4862;found:405.4857.
3',3',6',6'-四甲基-7-氯-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3f).白色粉末;M.p.:272 ℃(Lit.[25]270-271 ℃);IR(KBr)cm-1:3451,2959,1738,1666,1623,1348,1224,1131.1H NMR (CDCl3):δH(ppm)1.02(6 H,s,2 CH3),1.12(6 H,s,2 CH3),2.14and2.26(4 H,AB system,J=16.0 Hz,2 CH2),2.45and2.56(4 H,AB system,J=17.6 Hz,2 CH2),6.75(1 H,d,J=7.2 Hz,H-Ar),6.80(1 H,J=7.2 Hz,J=8.0 Hz,H-Ar),7.14(1 H,d,J=8.0 Hz,H-Ar),7.48(1 H,s,NH).13C NMR(CDCl3):δC(ppm)27.2,28.9,32.0,46.7,50.8,113.3,114.7,120.5,122.7,128.4,134.7,140.1,163.7,177.9,195.3.Anal.Calcd for C24H24ClNO4:C,67.68;H,5.68;N,3.29%.Found:C,67.53;H,5.61;N,3.18%.HRMS(ESI):m/z[M+H]+calcd for C24H24ClNO4:425.1394;found:425.1391.
3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3 g).白色粉末;M.p.:336-337 ℃(Lit.[15]336 ℃);1H NMR(CDCl3):δH(ppm)1.60-2.09(4 H,m,CH2),2.25-2.62(4 H,m,CH2),2.64(4 H,t,J=6.4 Hz,CH2),6.83-6.89(3 H,m,H-Ar),7.13-7.18(1 H,m,H-Ar),7.59(1 H,s,NH).13C NMR(CDCl3):δC(ppm)20.0,27.6,37.2,45.8,109.1,114.8,121.9,122.7,128.5,133.8,142.2,164.9,178.9,195.4.Anal. Calcd for C20H17NO4:C,71.63;H,5.11;N,4.18%.Found:C,71.52;H,5.03;N,4.35%.
5-甲基-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3 h).白色粉末;M.p.:288 ℃(Lit.[25]287-288 ℃);IR(KBr)cm-1:3312,2957,1743,1668,1618,1350,1314,1167.1H NMR(CDCl3):δH(ppm)1.83-2.10(4 H,m,CH2),2.23(3 H,s,CH3),2.26-2.66(4 H,m,CH2),2.64(4 H,t,J=6.8 Hz,CH2),6.67(1 H,s,H-Ar),6.72(1 H,d,J=8.0 Hz,H-Ar),6.95(1 H,d,J=7.6 Hz,H-Ar),7.59(1 H,s,NH).13C NMR(CDCl3):δC(ppm)20.0,21.2,27.6,37.2,45.9,108.8,114.9,123.7,128.9,131.2,133.7,139.7,167.9,178.9,195.5.Anal.Calcd for C21H19NO4:C,72.19;H,5.48;N,4.01%. Found:C,71.67;H,5.33;N,4.15%. HRMS(ESI):m/z[M+H]+calcd for C21H19NO4:349.1314;found:349.1310.
5-氯-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3 i).白色粉末;m.p.:>350 ℃;IR(KBr)cm-1:3455,2959,1747,1670,1637,1349,1228,1175.1H NMR(CDCl3):δH(ppm)1.97-2.10(4 H,m,CH2),2.23(3 H,s,CH3),2.29-2.37(4 H,m,CH2),2.65(4 H,t,J=6.4Hz,CH2),6.77(1 H,d,J=8.0 Hz,H-Ar),6.84(1 H,d,J=2.0 Hz,H-Ar),7.13(1 H,dd,J=2.0 Hz,J=8.0 Hz,H-Ar),7.60(1 H,s,NH).13C NMR(CDCl3):δC(ppm)19.9,27.5,37.1,46.0,110.0,114.4,123.2,127.0,128.3,135.3,140.9,165.3,178.4,195.4.Anal.Calcd for C20H16ClNO4:C,64.96;H,4.36;N,3.79%.Found:C,64.87;H,4.28;N,3.61%.HRMS(ESI):m/z[M+H]+calcd for C20H16ClNO4:369.0768;found:369.0764.
5-氟-3',3',6',6'-四甲基-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3 j).白色粉末;M.p.:301 ℃(Lit.[25]302-303 ℃);IR(KBr)cm-1:3457,2958,1732,1667,1618,1492,1349,1222,1167.1H NMR(CDCl3):δH(ppm)1.04(6 H,s,2 CH3),1.12(6 H,s,2 CH3),2.15and2.27(4 H,AB system,J=16.0 Hz,2 CH2),2.45and2.57(4 H,AB system,J=17.6 Hz,2 CH2),6.60(1 H,dd,J=2.0 Hz,J=7.6 Hz,H-Ar),6.72(1 H,J=4.4 Hz,J=8.4 Hz,H-Ar),6.80-6.85(1 H,m,H-Ar),8.16(1 H,s,NH).13C NMR(CDCl3):δC(ppm)27.3,28.9,32.0,41.2,46.2,50.9,110.1,113.3,114.6,134.9,138.6,157.7,160.1,163.8,178.7,195.4.Anal.Calcd for C24H24FNO4:C,70.40;H,5.91;N,3.42%.Found:C,69.93;H,5.86;N,3.35%.HRMS(ESI):m/z[M+H]+calcd for C24H24FNO4: 409.1689;found:409.1685.
5-溴-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3 k).白色粉末;M.p.:287 ℃(Lit.[25]288-289 ℃);IR(KBr)cm-1:3447,2959,1733,1668,1619,1495,1349,1224,1169.1H NMR(CDCl3):δH(ppm)1.98-2.10(4H,m,2 CH2),2.29-2.37(4 H,m,2 CH2),2.65(4 H,t,J=6.4 Hz,2 CH2),6.72(1 H,d,J=8.4 Hz,H-Ar),6.97(1 H,d,J=1.6 Hz,H-Ar),7.25-7.28(1 H,m,H-Ar),7.71(1 H,s,NH).13C NMR(CDCl3):δC(ppm)19.9,27.5,37.1,45.9,110.5,114.3,114.4,125.9,131.2,135.7,141.4,165.3,178.3,195.4.Anal.Calcd for C20H16BrNO4:C,57.99;H,3.89;N,3.38%.Found:C,57.71;H,3.81;N,3.42%.HRMS(ESI):m/z[M+H]+calcd for C20H16BrNO4:413.0263;found:413.0259.
5-溴-3',3',6',6'-四甲基-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3 l).白色粉末;M.p.:290 ℃(Lit.[15]290 ℃);IR (KBr)cm-1:3449,2958,1731,1665,1617,1347,1223,1165.1H NMR(CDCl3):δH(ppm)1.05(6 H,s,2 CH3),1.11(6 H,s,2 CH3),2.15and2.25(4 H,AB system,J=16.4 Hz,2 CH2),2.47and2.56(4 H,AB system,J=17.6 Hz,2 CH2),6.72(1 H,d,J=8.4 Hz,H-Ar),6.95(1 H,d,J=2.0 Hz,H-Ar),7.26(1 H,m,H-Ar),7.98(1 H,s,NH).13C NMR(CDCl3):δC(ppm)27.5,28.7,32.0,41.2,45.8,50.9,110.9,113.2,114.3,125.5,131.3,135.6,141.5,164.0,178.4,195.6.Anal.Calcd for C24H24BrNO4:C,61.28;H,5.14%;N,2.98%.Found:C,61.03;H,5.17;N,2.92%.
6-氟-3',3',6',6'-四甲基-3',4',6',7'-四氫螺[吲哚-3,9'-氧雜蒽]-1',2,8'(2'H,5'H)-三酮(3 m).白色粉末;M.p.:283 ℃(Lit.[25]281-283 ℃);IR(KBr)cm-1:3453,2959,1739,1664,1619,1347,1223,1130.1H NMR (CDCl3):δH(ppm)1.04(6 H,s,2 CH3),1.13(6 H,s,2 CH3),2.15and2.28(4 H,AB system,J=16.4 Hz,2 CH2),2.46and2.58(4 H,AB system,J=17.6 Hz,2 CH2),6.74(1 H,d,J=6.8 Hz,H-Ar),6.70-7.03(1 H,m,H-Ar),8.03(1 H,s,NH).13C NMR(CDCl3):δC(ppm)27.2,28.9,32.0,41.2,45.4,50.9,112.9,113.2,121.9,123.4,124.8,132.6,143.6,163.8,178.6,195.5.Anal.Calcd for C24H24FNO4:C,70.40;H,5.91;N,3.42%.Found:C,69.99;H,5.85;N,3.47%.HRMS(ESI):m/z[M+H]+calcd for C24H24FNO4:409.1689;found:409.1685.
實驗中,以靛紅和5,5-二甲基-1,3-環(huán)己二酮作為模型反應(yīng)底物,結(jié)果如表1 所示.首先是催化劑的篩選,無水乙醇中,選取了Cu(OTf)2、FeCl3和p-TSA(投料1 ~3)為催化劑進行反應(yīng),從表中可以看出,Cu(OTf)2和p-TSA 收率都較高,但前者可以方便地回收使用,因此,實驗中選Cu(OTf)2作為催化劑.其次是不同溶劑下反應(yīng)的進行情況(投料1,4 ~7),經(jīng)篩選,該反應(yīng)在乙醇進行時收率最好(投料1).最后是催化劑的用量選擇(投料1,8 和9),從表中可以看出,只需要底物靛紅的10% mol 量即可使反應(yīng)順利完成.反應(yīng)混合物在整個反應(yīng)過程中呈懸浮狀態(tài).隨著反應(yīng)的進行,反應(yīng)混合物的顏色由淺紅色變?yōu)闇\黃色.
表1 不同反應(yīng)條件對合成螺[吲哚-3,9'-氧雜蒽]三酮的影響
在上述篩選的最優(yōu)條件下,利用各類取代靛紅和不同的1,3-環(huán)己二酮制備了13 個氧雜蒽三酮類化合物,結(jié)果見表2.薄層色譜法(TLC)跟蹤反應(yīng)至結(jié)束,對所得固體進行過濾并用乙醇水溶液洗滌,得到粗產(chǎn)物,然后再用乙醇重結(jié)晶,得到純的取代氧雜蒽三酮類物質(zhì).所有產(chǎn)物均進行熔點、元素分析和核磁表征.從表中可看出,靛紅上的取代基,不管是吸電子還是供電子基團,均能使反應(yīng)順利完成.
研究了催化劑的回收使用.以靛紅、5,5-二甲基-1,3-環(huán)己二酮為原料,反應(yīng)完成后,冷卻析出結(jié)晶,過濾得粗產(chǎn)物,然后加入水和乙酸乙酯,分離得到水層,減壓除水,回收得到的Cu(OTf)2,在120 ℃干燥6 h 即可重新使用.經(jīng)過4次循環(huán)使用,仍有很高的活性.結(jié)果見表3.
表2 螺[吲哚-3,9'-氧雜蒽]三酮的合成
表3 催化劑Cu(OTf)2回收使用情況
綜上所述,本文主要研究了以Cu(OTf)2為催化劑,乙醇為溶劑,靛紅和1,3-環(huán)己二酮一鍋法合成螺[吲哚-3,9'-氧雜蒽]三酮的方法,通過變換底物合成了13 個化合物,均通過核磁、紅外和元素分析的表征.并對Cu(OTf)2的回收使用做了研究,結(jié)果表明循環(huán)使用4 次,催化劑還是能保持較高的活性.本方法具有操作簡便、條件溫和以及環(huán)境友好的特點.