王 柳, 巨修練
(武漢工程大學(xué)化工與制藥學(xué)院,湖北省新型反應(yīng)器與綠色化學(xué)工藝重點實驗室,湖北 武漢 430074)
1,3,4-噁二唑雜環(huán),具有殺蟲、消炎、殺菌等作用[1-4],在農(nóng)藥、醫(yī)藥等領(lǐng)域有著廣泛應(yīng)用.研究發(fā)現(xiàn),某些2,5-二取代-1,3,4-噁二唑雜環(huán)化合物具有抗腫瘤活性[5-7],或抗驚厥活性[8-9].
本實驗以圖1所示的化合物為先導(dǎo)化合物,根據(jù)電子等排原理對其進行結(jié)構(gòu)修飾[10].
圖1 先導(dǎo)化合物
分別以水楊酸和鄰氨基苯甲酸為起始原料,合成了6個未見文獻報道的2,5-二取代-1,3,4-噁二唑類化合物,以期從中尋找到具有一定抗腫瘤活性的雜環(huán)化合物.合成路線如圖2所示.
圖2 目標化合物的合成
RY-1型熔點儀;Varian Mercury-Vx300型核磁共振儀(TMS為內(nèi)標,300 MHz);FINNIGAN TRACE GC-MS型質(zhì)譜儀;Vario ELⅢ型元素分析儀.
水楊酸,分析純,國藥集團化學(xué)試劑有限公司生產(chǎn);鄰胺基苯甲酸,分析純,國藥集團化學(xué)試劑有限公司生產(chǎn);異硫氰酸苯酯和異硫氰酸對甲苯酯按文獻[11]合成;柱層析硅膠,孔徑45~75 μm,青島海洋化工廠;實驗中所用試劑均為化學(xué)純或分析純,除特別注明外,未經(jīng)進一步處理.
1.2.1 中間體1a的合成 于100 mL燒瓶中加入6.9 g (50 mmol) 水楊酸和40 mL甲醇,攪拌使固體溶解.滴加2 mL濃硫酸后,升溫至回流.TLC跟蹤反應(yīng)(展開劑為V乙酸乙酯∶V正己烷=1∶1).反應(yīng)結(jié)束后,減壓脫溶.加入30 mL水,用乙酸乙酯萃取(20 mL×3),收集油層,用飽和NaHCO3溶液洗滌至中性,用飽和食鹽水洗滌,用無水MaSO4干燥,過濾,蒸干溶劑.產(chǎn)品為無色油狀物4.996 g(1a),產(chǎn)率60%.
1.2.2 中間體2a的合成[12]于50 mL三口燒瓶中投入0.56 g (10 mmol ) KOH和20 mL乙腈溶液,加熱使固體盡量溶解.稍冷,投入1.64 g (10 mmol) 水楊酸甲酯,攪拌片刻.將2.53 g (20 mmol) 芐氯溶入10 mL乙腈中,緩慢滴入三口燒瓶.滴畢,升溫至回流,TLC跟蹤反應(yīng)(展開劑為V乙酸乙酯∶V石油醚= 1∶8).反應(yīng)結(jié)束后,減壓脫溶.加入20 mL水,用乙酸乙酯萃取(20 mL×3),收集油層,用飽和食鹽水洗滌,用無水MaSO4干燥,過濾,蒸干溶劑.柱層析提純分離(洗脫劑為V乙酸乙酯∶V石油醚=1∶10),產(chǎn)物為無色透明狀液體0.847 g(2a),產(chǎn)率33%.
1.2.3 中間體3a的合成 于50 mL三口燒瓶中投入1.28 g (5 mmol)2a和25 mL乙醇溶液,攪拌升溫至60 ℃,將1.25 g(25 mmol)水合肼溶入10 mL乙醇溶液中,緩慢滴入三口燒瓶.滴畢,升溫至回流,TLC跟蹤反應(yīng)(展開劑為V乙酸乙酯∶V石油醚=1∶1).反應(yīng)結(jié)束后,減壓脫溶.反應(yīng)物為油狀,加入10 mL水,過濾,用石油醚淋洗固體,烘干,得白色固體0.653 g (3a), 收率54%.
1.2.4 中間體4a的合成 將0.65 g(2.7 mmol) 中間體3a與0.4 g(3 mmol)異硫氰酸苯酯投入50 mL燒瓶中,投入乙醇25 mL,回流1 h,冷卻至室溫,靜置過夜后,有白色針狀晶體析出,過濾,濾餅用乙醇淋洗,得中間體0.892 g (4a),產(chǎn)率88%.
1.2.5 目標化合物5a的合成[13]將0.377 g(1 mmol)中間體4a與0.32 g(1 mmol) Hg(OAc)2投入到50 mL燒瓶中.加入30 mL乙醇,回流3 h,待反應(yīng)混合物完全變成黑色,趁熱過濾,直到黑色固體全部濾出,濾液冷卻至室溫,有固體析出,用乙醇重結(jié)晶,得到目標化合物 155 mg (5a),產(chǎn)率45%.
以相同的路線制得5b-5f.
2-苯氨基-5-(2-芐氧基苯基)-1,3,4-噁二唑(5a):白色晶體,收率45.3%. 熔點:160~162 ℃.1H NMR(DMSO-d6,300 MHz):δ= 5.36 (s, 2H, CH2), 7.03 (t, 1H, NHph-H4), 7.19 (d, 2H, ph-H3,H5), 7.31 (t, 2H, NHph-H3,H5), 7.38 (t, 2H, NHph-H2,H6), 7.52 (t, 1H, ph-H4), 7.62 (m, 4H, CH2ph-H2,H3,H5,H6), 7.85 (d, 1H, ph-H6), 10.59 (s, 1H, NH). MS m/z (%):343(M+, 16), 225(24), 120(98), 92(63), 91 (100), 77(66). Anal. calcd for C21H17N3O2:C 73.45, H 4.99, N 12.24. found C 73.18, H 4.39, N 12.07.
2-對甲苯基氨基-5-(2-芐氧基苯基)-1,3,4-噁二唑(5b):白色晶體,收率57.1%. 熔點:159~161 ℃.1H NMR(Acetone-d6,300MHz):δ=2.29 (s, 3H, CH3), 5.63 (s, 2H, CH2), 7.12 (t, 1H, CH2ph-H4), 7.18 (d, 2H, ph-H3,H5), 7.31 (t, 2H, NHph-H3,H5), 7.38 (t, 2H, NHph-H2,H6), 7.52 (t,1H, ph-H4), 7.61 (m, 4H, CH2ph-H2,H3,H5,H6), 7.85 (d, 1H, ph-H6), 10.54 (s, 1H, NH). MS m/z (%): 357 (M+, 16), 251 (44), 225 (13), 106 (63), 91 (100), 77 (48). Anal. calcd for C22H19N3O2: C 73.97, H 5.36, N 11.76. found C 73.79, H 5.12, N 11.73.
2-苯氨基-5-[2-(4-氯-3-吡啶基)芐氧基]苯基-1,3,4-噁二唑(5c):白色絮狀固體,收率67.0%. 熔點:199~200 ℃.1H NMR (DMSO-d6, 300MHz):δ= 5.36 (s, 2H, CH2), 7.03 (t, 1H, NHph-H4), 7.19~ 7.34 (t, 3H, Ph-H5, NHph-H3,H5), 7.54~ 7.61 (m,4H, NHph-H2,H6, pyrimidine-H3, ph-H4), 7.79 (dd, 1H, pyrimidine-H4), 8.05 (dd,1H, ph-H6), 8.65 (d, 1H, pyrimidine-H5), 10.59 (s, 1H, NH). MS m/z (%):378(M+, 16), 286 (34), 260(53), 126 (17), 92 (100), 77 (72). Anal. calcd for C20H15ClN4O2:C 63.41, H 3.99, N 14.79. found C 63.88, H 3.79, N 14.73.
2-苯氨基-5-[2-(2-吡啶基)芐氧基]-1,3,4-噁二唑(5d):白色針狀晶體,收率37.9%. 熔點:174~175 ℃. 1H NMR(CDCl3,300MHz):δ=5.37(s, 2H, CH2), 7.06~ 7.11 (q,3H, NHph-H4, ph-H3,H5), 7.21 (t, 1H, ph-H4), 7.36 (t, 2H, NHph-H3,H5), 7.45 (t, 1H, pyrimidine-H5), 7.55 (d, 2H, NHph-H2,H6), 7.67 (t, 1H, pyrimidine-H3), 7.84 (t, 2H, ph-H6, pyrimidine-H4), 7.91 (t, 1H, py-H6), 8.58 (d, 1H, NH); MS m/z (%):344 (M+, 57), 252 (23), 226 (40), 134 (76), 92 (100), 77 (58); Anal. calcd for C20H16N4O2:C 69.76, H 4.68, N 16.27. found C 69.24, H 4.79, N 16.59.
2-苯氨基-5-(2-芐氨基苯基)-1,3,4-噁二唑(5e):白色晶體,收率27.4%. 熔點:225~227 ℃.1H NMR(DMSO-d6,300MHz):δ= 4.56 (d, 2H, CH2), 5.75 (s, 1H, NH), 6.74 (t, 1H, ph-H5), 6.83 (d, 1H, ph-H3), 7.02 (t, 1H, NHph-H4), 7.27~ 7.38 (m, 7H, NHph-H3,H5, NHCH2ph-H), 7.62 (d, 3H, NHph-H2,H6, ph-H3), 7.84 (bs, 1H, ph-H6), 10.69 (s, 1H, NH). MS m/z (%):342 (M+, 34), 249 (12), 207 (17), 193 (100), 91 (90), 77 (33). Anal. calcd for C21H18N4O:C 73.67, H5.30,N 16.36.found C 72.98, H 5.10, N 16.30.
2-對甲苯基氨基-5-(2-芐氨基苯基)-1,3,4-噁二唑(5f):白色絮狀固體,收率29.2%. 熔點:233~235 ℃.1H NMR(DMSO-d6,300MHz) :δ= 2.31 (s, 3H, CH3), 4.61 (d, 2H, CH2), 5.80 (s, 1H, NH), 6.78 (t, 1H, ph-H5), 6.88 (d, 1H, ph-H3), 7.23 (d, 2H, CH2ph-H2,H6), 7.34 (d, 2H, CH3ph-H2,H6), 7.41 (m, 3H, CH2ph-H3,H4,H5), 7.56 (d, 2H, CH3ph-H3,H5), 7.67 (d, 1H, ph-H4), 7.89 (bs, 1H, ph-H6), 10.62 (s, 1H, NH). MS m/z (%):356 (M+, 27), 249 (16), 207 (35), 193 (81), 107 (75), 92 (98)77 (58). Anal. calcd for C22H20N4O:C 74.14, H 5.66, N 15.72. found C 73.94, H 5.41, N 15.75.
本實驗以水楊酸和鄰氨基苯甲酸為起始原料,經(jīng)過酯化,威廉反應(yīng),肼解,取代,環(huán)合五步反應(yīng)合成了6個2,5-二取代-1,3,4-噁二唑類雜環(huán)化合物. 化合物未見文獻報道. 其中,第二步威廉反應(yīng),反應(yīng)時間最長,并且要用到柱層析的方法來提純,產(chǎn)率最低,因此是整條路線的關(guān)鍵步驟.該步反應(yīng)的堿選用KOH,乙腈做溶劑產(chǎn)率較高.筆者期望通過結(jié)構(gòu)修飾發(fā)現(xiàn)具有一定抗腫瘤活性的化合物.
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