汪秋安 李興 徐雨 汪鋼強(qiáng)
摘 要:阿魏酸及其酰胺類化合物是一類具有重要生物活性和藥理作用的天然產(chǎn)物及其衍生物.本論文以廉價(jià)易得的香蘭素為原料,經(jīng)克腦文蓋爾(Knoevenagel)縮合反應(yīng)得到阿魏酸(1).然后以N,N′-二環(huán)己基碳酰亞胺(DCC)為脫水劑,4-二甲氨基吡啶(DMAP)為催化劑,阿魏酸分別與8種芳香胺反應(yīng)合成了8種阿魏酸酰胺類化合物2-9.其中7和8是未見(jiàn)文獻(xiàn)報(bào)道的新化合物.所合成的阿魏酸酰胺類化合物通過(guò)核磁共振氫譜(1H NMR)、核磁共振碳譜(13C NMR)、質(zhì)譜(MS)和紅外光譜(IR) 進(jìn)行了結(jié)構(gòu)表征.該阿魏酸酰胺類化合物合成方法原料易得、工藝簡(jiǎn)便、收率較高.
關(guān)鍵詞:阿魏酸;阿魏酸酰胺;合成;結(jié)構(gòu)表征
中圖分類號(hào):O622.5文獻(xiàn)標(biāo)志碼:A
Abstract:Ferulic acid and ferulamides are a class of natural products and derivatives with important biological activity and pharmacological effect. Ferulic acid (1) was synthesized from vanillin through Knoevenagel reaction. Then, a series of ferulamides (2-9) were synthesized through reaction of ferulic acid with amines using DCC as dehydrating agent and DMAP as the catalyst. Compounds 7 and 8 are new compounds. The structures of all synthetic compounds were characterized by NMR、MS and IR spectra. This synthetic method has the advantages of easy availability of starting materials, simple operation and high yield.
Key words:ferulic acid; ferulamides; synthesis; structure characterization
阿魏酸(ferulic acid, FA)化學(xué)名為4-羥基-3-甲氧基苯丙烯酸,是植物界普遍存在的一種酚酸,在細(xì)胞壁中與多糖和蛋白質(zhì)結(jié)合成細(xì)胞壁的骨架,廣泛存在于川芎、當(dāng)歸、紅花、升麻、木賊和阿魏等中草藥中,常作為中藥成份及其制劑中定性定量的化學(xué)指標(biāo)用于評(píng)價(jià)和控制制劑的質(zhì)量.阿魏酸的藥理活性有抗氧化和清除自由基[1]、抗癌和抗突變[2]、增強(qiáng)免疫[3]、對(duì)心血管系統(tǒng)[4]的作用等,被廣泛應(yīng)用于醫(yī)藥、農(nóng)藥、保健品、化妝品原料和食品添加劑等方面.
Lee等[5]發(fā)現(xiàn)阿魏酸酰胺類天然產(chǎn)物在U937細(xì)胞中抑制依托泊苷誘導(dǎo)細(xì)胞凋亡.Nesterenko等[6]設(shè)計(jì)合成的一系列阿魏酸酰胺衍生物能誘導(dǎo)U937和HL60凋亡.Okombi等[7]將阿魏酸與胺、氨基酸和雜環(huán)中的氨基反應(yīng)生成了具有抑制人黑色素細(xì)胞酪氨酸酶作用的阿魏酸酰胺類化合物.Jung等[8]合成了具有抗氧化作用阿魏酸酰胺類化合物.此外,阿魏酸酰胺類化合物還具有降血壓[9]、乙酰膽堿脂酶抑制劑[10]和促進(jìn)胰島素分泌[11]等藥理活性.為了進(jìn)一步研究阿魏酸酰胺類化合物的生物活性以及藥物開(kāi)發(fā)的需要.我們合成了一系列阿魏酸酰胺類化合物2-9(如圖1所示),其中7和8是未見(jiàn)文獻(xiàn)報(bào)道的新化合物.所合成的阿魏酸酰胺類化合物通過(guò)核磁共振氫譜(1H NMR)、核磁共振碳譜(13C NMR)、質(zhì)譜(MS)和紅外光譜(IR) 進(jìn)行了結(jié)構(gòu)表征.
1 實(shí)驗(yàn)部分
1.1 儀器和試劑
熔點(diǎn)由XT-4型雙目顯微熔點(diǎn)測(cè)定儀測(cè)定,溫度計(jì)未校正;IR由FT-5DX型紅外光譜儀,KBr壓片法測(cè)定;1HNMR和13CNMR由Varian INOVA-400型和Bruker-AV 400型核磁共振儀(溶劑CDCl3或DMSO-d6,TMS為內(nèi)標(biāo))測(cè)定,其中1HNMR均在400 MHz下測(cè)定,13CNMR均在101 MHz下測(cè)定;MS由ZAB-HS型質(zhì)譜儀測(cè)定.所有試劑和溶劑均為商品化的化學(xué)純或分析純級(jí).要求無(wú)水的溶劑均經(jīng)除水和重蒸處理.
1.2 阿魏酸(1)的合成
在裝有回流冷凝管、溫度計(jì)的100 mL三頸圓底燒瓶中加入3-甲氧基-4-羥基苯甲醛6.10 g (0.04 mol),丙二酸5.20 g (0.05 mol),再加入5 mL無(wú)水吡啶和15 mL無(wú)水甲苯的混合溶劑,使之溶解后,滴加0.5 mL苯胺,控制反應(yīng)瓶?jī)?nèi)的溫度在90~95 ℃,磁力攪拌反應(yīng)5 h,反應(yīng)完畢.冷卻至室溫,邊攪拌邊加入25 mL 25% K2CO3水溶液,有固體析出.加熱溶解,趁熱用分液漏斗分出水層,水層用鹽酸調(diào)節(jié)pH值為2左右,在此酸化的過(guò)程中有大量的氣體冒出并伴有乳白色的固體生成.抽濾,并用1.0 mol·L-1的稀鹽酸洗滌(10 mL×3)濾餅,然后用熱水重結(jié)晶,得到白色針狀晶體6.73 g,產(chǎn)率86%. m.p. 170-171 ℃ [文獻(xiàn)[12]m.p. 172.5-173.5 ℃]. 1H NMR (400 MHz, DMSO-d6) δ 9.57 (1H, s, COOH), 7.49 (1H, d, J = 15.9 Hz, α-H ), 7.28 (1H, d, J = 1.8 Hz, 2-H), 7.08 (1H, dd, J = 8.2, 1.8 Hz, 5-H), 6.78 (1H, d, J = 6.6 Hz, 6-H), 6.37 (1H, d, J = 15.9 Hz, β-H), 3.82 (3H, s, 3-OCH3). MS (ESI) m/z: 193[M-H]+.
1.3 阿魏酸酰胺類化合物2-9的合成
在氮?dú)獗Wo(hù)條件下,在100 mL干燥的單口圓底燒瓶中,將0.22 mmol 4,4-二甲基吡啶(DMAP)溶于30 mL干燥的THF中,再加入2.2 mmol相對(duì)應(yīng)的胺和42.4 mmol 阿魏酸.冰水浴冷至0 ℃,攪拌反應(yīng)30 min,然后在0 ℃時(shí)加入4.4 mmol N,N
-二環(huán)己基碳酰亞胺(DCC),胺、酸、DCC、DMAP的物質(zhì)的量比為1∶1.1∶2∶0.1.反應(yīng)溫度自然升至室溫,薄層色譜檢測(cè)反應(yīng)完成后,停止反應(yīng).過(guò)濾,去除白色不溶物N,N-二環(huán)己基脲(DCU),旋除濾液中THF,殘留黃色油狀物加適量水后用乙酸乙酯萃取3次(10 mL×3),再用CH2Cl2萃取3次(10 mL × 3),合并有機(jī)相后,飽和食鹽水洗滌3次(20 mL × 3),無(wú)水Na2SO4干燥,過(guò)濾,減壓蒸餾除去溶劑.快速硅膠柱層析,用石油醚和乙酸乙酯按13∶1~3∶1體積比洗脫,得到2-9的純化合物.
(E)-3-(3-甲氧基-4-羥基苯基)-N-苯基丙烯酰胺(2):黃色固體,產(chǎn)率72%.m.p. 128-130 °C.IR (KBr) v: 3 340, 3 058, 2 930, 2 850, 2 360, 1 655, 1 585, 1 514, 1 354, 1 277, 1 159, 1 120, 1 027, 816, 766, 660 cm-1. 1H NMR (400 MHz, CDCl3) δ 8.13 (1H, s, NH), 7.61 (2H, d, J = 8.2 Hz,2'-H,6'-H), 7.43 (2H, t, J = 7.8 Hz, 3'-H, 5'-H), 7.28 (1H, d, J = 15.6 Hz, α-H), 7.10 (1H, t, J = 7.3 Hz, 4'-H), 7.01 (1H, s, 2-H), 6.91 (1H, d, J = 15.6 Hz, β-H), 6.85 (1H, d, J = 8.2 Hz, 5-H), 6.50 (1H, dd, J = 8.7,2.3 Hz, 6-H), 3.80 (3H, s, 3-OCH3); 13C NMR (101 MHz, CDCl3) δ 147.49, 146.58, 142.22, 138.10, 128.90, 127.02, 124.12, 122.06, 119.79, 114.65, 109.78, 55.74, 33.81, 25.42, 24.78. MS (ESI) m/z: 270[M+H]+.
(E)-3-(3-甲氧基-4-羥基苯基)-N-(鄰甲基苯基)丙烯酰胺(3):白色固體,產(chǎn)率68%. m.p. 185-186 °C.IR (KBr) v: 3 333, 3 272, 2 927, 2 850, 2 360, 1 658, 1 629, 1 597, 1 527, 1 450, 1 428, 1 245, 1 117, 963, 745, 611 cm-1. 1H NMR (400 MHz, CDCl3) δ 7.91 (1H, s, NH)7.69 (1H, d, J = 15.8 Hz, α-H), 7.65(1H, dd, J = 8.0,1.4 Hz, 3'-H), 7.39 (1H, dd, J =8.0,1.5 Hz, 6'-H), 7.25 (1H, t, J = 8.9 Hz, 5'-H), 7.08 (1H, s, 2-H), 7.07 (1H, t, J = 8.0 Hz, 4'-H), 6.99 (1H, d, J = 15.8 Hz, β-H), 6.90 (1H, d, J = 8.2 Hz, 5-H), 6.49 (1H, dd, J = 8.2,1.6 Hz, 6-H), 3.89 (3H, s, 3-OCH3), 2.30 (3H, s, 2'-CH3); 13C NMR (101 MHz, CDCl3) δ 156.92, 147.63, 146.72, 142.32, 135.78, 130.44, 127.09, 126.69, 125.22, 123.26, 122.21, 118.15, 114.76, 109.88, 55.86, 17.83. MS (ESI) m/z: 284 [M+H]+.
(E)-3-(3-甲氧基-4-羥基苯基)-N-(間甲基苯基)丙烯酰胺(4):黃色固體,產(chǎn)率70%. m.p. 66-69 °C.IR (KBr) v: 3 341, 3 272, 2 983, 2 866, 2 360, 1 658, 1 629, 1 597, 1 527, 1 450, 1 428, 1 364, 1 245, 1 155, 963, 745, 644 cm-1. 1H NMR (400 MHz, CDCl3) δ 7.60 (1H, s, NH), 7.56 (1H, d, J = 15.7 Hz, α-H), 7.41 (1H, dd, J = 7.8,1.8 Hz, 6'-H), 7.33 (1H, s, 2'-H), 7.18 (1H, s, 2-H), 7.13 (1H, t, J = 7.8Hz,5'-H), 6.98 (1H, dd, J = 8.2, 1.8 Hz, 4'-H), 6.89 (1H, d, J = 15.7 Hz, β-H), 6.85 (1H, d, J = 8.2 Hz, 5-H), 6.81 (1H, dd, J = 8.2,2.4 Hz, 6-H), 3.79 (3H, s, 3-OCH3), 2.25 (3H, s, 3'-CH3); 13C NMR (101 MHz, CDCl3) δ 164.38, 147.53, 146.64, 142.23, 138.91, 138.05, 128.81, 127.13, 125.05, 122.17, 120.52, 118.41, 116.92, 114.71, 109.79, 55.83, 21.48.MS (ESI) m/z: 284 [M+H]+.
(E)-3-(3-甲氧基-4-羥基苯基)-N-(對(duì)甲基苯基)丙烯酰胺(5): 白色固體,產(chǎn)率75%. m.p. 213-214 °C.IR (KBr) v: 3 336, 3 272, 2 927, 2 850, 1 658, 1 629, 1 597, 1 527, 1 514, 1 450, 1 428, 1 264, 1 155, 938, 826, 770 cm-1. 1H NMR (400 MHz, DMSO-d6) δ 10.03 (1H, s, NH), 9.60 (1H, s, 4-OH), 7.56 (2H, dd, J = 8.2,2.4 Hz, 3'-H,5'-H), 7.45 (1H, d, J = 15.5 Hz, α-H), 7.16 (1H, s, 2-H), 7.11 (2H, dd, J = 8.2,1.9 Hz, 2'-H, 6'-H), 7.06 (1H, d, J = 15.5 Hz, β-H), 6.81 (1H, d, J = 8.1 Hz, 5-H), 6.61 (1H, dd,J = 8.1,2.3 Hz, 6-H), 3.81 (3H, s, 3-OCH3), 2.07 (3H, s, 4'-CH3); 13C NMR (101 MHz, DMSO-d6) δ 164.32, 148.99, 148.30, 140.88, 137.32, 132.60, 129.59, 126.67, 122.37, 119.58, 119.33, 116.12, 111.26, 55.99, 20.90.MS (ESI) m/z: 284 [M+H]+.
(E)-N-芐基-3(3-甲氧基-4-羥基苯基)丙烯酰胺(6):白色固體,產(chǎn)率66%.m.p. 116-117 °C. IR (KBr) v: 3 328, 3 066, 2 933, 2 864, 1 637, 1 575, 1 514, 1 378, 1 231, 1 133, 1 090, 816, 755, 691 cm-1. 1H NMR (400 MHz, CDCl3) δ 7.59 (1H, d, J = 15.5 Hz, α-H), 7.33 (2H, t, J = 8.2 Hz,3'-H, 5'-H), 7.31 (2H, dd, J = 7.6,2.5 Hz, 2'-H, 6'-H), 7.03(1H, s, 2-H), 7.27(1H, dd, J = 8.2, 1.8 Hz, 4'-H), 6.96 (1H, d, J = 8.2 Hz, 5-H), 6.89 (1H, dd, J = 8.2,1.7 Hz, 6-H), 6.31 (1H, d, J = 15.5 Hz, β-H), 4.55 (2H, s, NCH2), 3.86 (3H, s, 3-OCH3); 13C NMR (101 MHz, CDCl3) δ 166.18, 147.47, 146.73, 141.37, 138.18, 128.64, 127.78, 127.44, 127.14, 122.02, 117.86, 114.75, 109.68, 55.80, 43.75. MS (ESI) m/z: 284[M+H]+.
(E)-3-(3-甲氧基-4-羥基苯基)-N-(2-羥基苯基)丙烯酰胺(7):白色固體,產(chǎn)率63%. m.p. 185 -186 °C.IR (KBr) v: 3 327, 3 275, 2 926, 2 840, 2 362, 1 668, 1 622, 1 590, 1 424, 1 360, 1 341, 1 148, 1 036, 962, 818, 741, 607, 536 cm-1. 1H NMR (400 MHz, DMSO-d6) δ 9.37 (1H, s, NH), 7.91 (1H, d, J =7.8 Hz, 6'-H), 7.69 (1H, d, J = 15.7 Hz, α-H), 7.46 (1H, t, J = 8.5 Hz, 4'-H), 7.23 (1H, s, 2-H ), 7.06 (1H, t,J = 8.1 Hz, 5'-H), 6.93 (1H, dd, J = 8.1,1.8 Hz, 3'-H), 6.88 (1H, d, J = 15.7 Hz, β-H), 6.81 (1H, d, J = 7.1 Hz, 5-H), 6.78 (1H, d, J = 7.1,1.9 Hz, 6-H), 5.59 (1H, s, 2'-OH), 3.83 (3H, s, 3-OCH3); 13C NMR (101 MHz, DMSO-d6) δ 169.61, 153.73, 152.96, 152.58, 145.90, 131.85, 131.42, 129.56, 127.39, 126.64, 124.19, 123.89, 120.85, 120.70, 115.77, 60.61. HRMS (EI) :m/z Calcd for C16H15NO4, 285.100, Found 285.0996(M).
(E)-3-(3-甲氧基-4-羥基苯基)-N-(3-羥基苯基)丙烯酰胺(8):白色固體,產(chǎn)率67%. m.p. 162 -163 °C.IR (KBr) v: 3 331, 3 276, 2 926, 2 850, 2 362, 1 668, 1 628, 1 596, 1 424, 1 360, 1 345, 1 148, 1 036, 962, 818, 743, 615, 536 cm-1. 1H NMR (400 MHz, DMSO-d6) δ 10.03 (1H, s, NH), 9.51 (2H, s, 4-OH, 3'-OH), 7.52 (1H, d, J = 15.6 Hz, α-H), 7.35 (1H, s, 2'-H), 7.23 (1H, s, 2-H), 7.15 (1H, t,J = 7.9 Hz, 5'-H), 7.12 (1H, dd, J = 8.9,2.0 Hz, 6'-H), 7.10 (1H, t,J = 9.0 Hz, 4'-H), 6.87 (1H, d, J = 8.1 Hz, 5-H), 6.68 (1H, d, J = 8.1,1.7 Hz, 6-H), 6.50 (1H, d, J =15.6 Hz, β-H), 3.88 (3H, s, 3-OCH3); 13C NMR (101 MHz, DMSO-d6) δ 168.94, 162.63, 153.63, 152.89, 145.53, 134.45, 131.25, 127.00, 124.01, 120.73, 115.78, 115.35, 114.98, 111.28, 60.54. HRMS(EI): m/z Calcd for C16H15NO4, 285.099, Found 285.0996(M).
(E)-3-(3-甲氧基-4-羥基苯基)-N-(4-羥基苯基)丙烯酰胺(9):白色固體,產(chǎn)率62%. m.p. 205-206 °C.IR (KBr) v: 3 327, 3 272, 2 930, 2 845, 2 360, 1 661, 1 629, 1 590, 1 424, 1 363, 1 241, 1 127, 1 036, 960, 818, 746, 637 cm-1. 1H NMR (400 MHz, DMSO-d6) δ 9.88 (1H, s, NH), 9.28 (1H, s, 4'-OH), 7.48 (1H, dd, J = 8.3,1.9 Hz, 2'-H), 7.46 (1H, dd, J = 8.3,2.5 Hz, 6'-H), 7.43 (1H, d, J = 15.6 Hz, α-H), 7.16 (1H, s, 2-H), 6.81 (2H, d, J = 8.1,2.1 Hz, 3'-H, 5'-H), 6.72 (1H, d, J = 6.5 Hz, 5-H), 6.70 (1H, dd, J = 6.5,1.3 Hz, 6-H), 6.59 (1H, d, J = 15.6 Hz, β-H), 5.60 (1H, s, 4-OH), 3.82 (3H, s, 3-OCH3); 13C NMR (101 MHz, DMSO-d6) δ 163.87, 153.72, 148.91, 148.31, 140.32, 131.65, 126.78, 122.25, 121.22, 119.58, 116.14, 115.60, 111.18, 55.97. MS (ESI) m/z: 286[M+H]+.
2 結(jié)果與討論
2.1 合成方法討論
本文第一步采用克腦文蓋爾(Knoevenagel)縮合反應(yīng)合成阿魏酸,這是合成α,β-不飽和酸的常用方法.首先將丙二酸以苯胺和吡啶為堿催化得到碳負(fù)離子,然后與香草醛發(fā)生縮合反應(yīng).該反應(yīng)需控制反應(yīng)溫度在90~95 ℃左右,原因是該反應(yīng)的產(chǎn)物有順?lè)磧煞N異構(gòu)體,而反式產(chǎn)物才是我們所需要的,經(jīng)過(guò)多次試驗(yàn)探索,當(dāng)反應(yīng)溫度過(guò)高(超過(guò)100 ℃),會(huì)得到順式油狀物.
本合成的關(guān)鍵步驟是酰胺化,我們以阿魏酸為原料,DCC/DMAP為催化劑,無(wú)水THF為溶劑,與多種胺反應(yīng).DCC(Dicyclohexylcarbodiimide,N,N′-二環(huán)己基碳酰亞胺)是一種常用的縮合劑,在此反應(yīng)中可活化羧基并起到脫水作用;DMAP(4-dimethylamiopryidine,4-二甲氨基吡啶)是一種新型的高效催化劑.與傳統(tǒng)的?;磻?yīng)相比較,DCC/DMAP催化酰胺化反應(yīng)具有反應(yīng)條件溫和(可以在室溫下進(jìn)行)、反應(yīng)時(shí)間短、反應(yīng)速度快(比吡啶催化快一萬(wàn)倍)、操作簡(jiǎn)便、產(chǎn)率較高等優(yōu)點(diǎn).DCC吸水后生成不溶于溶劑的N,N-二環(huán)己基脲(DCU),容易與產(chǎn)物分離.我們通過(guò)分析DCC-DMAP法合成阿魏酸酰胺類化合物的反應(yīng),發(fā)現(xiàn)反應(yīng)溶劑、催化劑、反應(yīng)溫度、加料順序和胺的極性大小等對(duì)反應(yīng)有著至關(guān)重要的影響.
2.1.1 反應(yīng)溶劑的選擇
在阿魏酸酰胺類化合物的合成過(guò)程中,曾在二氯甲烷、N,N-二甲基甲酰胺(DMF)、無(wú)水四氫呋喃等不同極性的溶劑中反應(yīng),實(shí)驗(yàn)結(jié)果表明,溶劑的極性大小對(duì)實(shí)驗(yàn)的成敗至關(guān)重要.在二氯甲烷中由于阿魏酸和胺類的溶解度較小,反應(yīng)1天,TLC檢測(cè)幾乎沒(méi)有反應(yīng);在N,N-二甲基甲酰胺體系中的反應(yīng),TLC檢測(cè)有反應(yīng),但是DMF沸點(diǎn)較高,后處理麻煩;在無(wú)水四氫呋喃體系中,通過(guò)TLC檢測(cè)發(fā)現(xiàn)在極性適中的THF體系中反應(yīng)效果最佳.
2.1.2 催化劑的選擇
催化劑的用量在一定范圍內(nèi),產(chǎn)率隨著催化劑用量的增加而升高,否則產(chǎn)率反而會(huì)下降.本文試驗(yàn)以DCC、DCC/DMAP、DCC/N,N-二甲基苯胺等3種不同催化劑組合制備阿魏酸酰胺類化合物,以DCC/DMAP催化效果最佳,DCC∶胺為2∶1(摩爾比),DMAP∶胺為0.1∶1(摩爾比)時(shí)收率最高.DCC/DMAP催化具有應(yīng)用范圍廣、反應(yīng)條件溫和、反應(yīng)時(shí)間短和產(chǎn)率較高等優(yōu)點(diǎn).
2.1.3 反應(yīng)溫度的選擇
在以阿魏酸為原料,DCC/DMAP為催化劑,THF為溶劑的反應(yīng)中,我們選擇剛開(kāi)始在0 oC左右反應(yīng),一段時(shí)間后,將其移至室溫.原因是反應(yīng)溫度太低時(shí),反應(yīng)速度較慢,反應(yīng)產(chǎn)物的收率也不高;反應(yīng)溫度太高時(shí),反應(yīng)速率過(guò)快,容易有副產(chǎn)物生成,反應(yīng)難以控制.
2.1.4 加料順序的選擇
從DCC/DMAP的催化反應(yīng)機(jī)理可以看出,阿魏酸的羧基先和DCC反應(yīng),然后再與胺的氨基反應(yīng)生成酰胺鍵.但是在實(shí)際的反應(yīng)過(guò)程中,加料順序?qū)Ψ磻?yīng)結(jié)果并無(wú)太大影響,可能是由于使用具有超強(qiáng)親核的?;饔么呋瘎〥MAP,其催化效果很好.
2.1.5 胺的選擇
反應(yīng)機(jī)理表明,當(dāng)苯環(huán)上引入供電子取代基時(shí),增加芳香胺的親核性,有助于酰胺化反應(yīng)的進(jìn)行,容易得到阿魏酸酰胺化合物.此外,2-氨基苯酚、3-氨基苯酚和對(duì)氨基苯酚都有氨基和酚羥基雙官能團(tuán),與阿魏酸反應(yīng)的產(chǎn)物應(yīng)該既有酰胺化產(chǎn)物又有酯化產(chǎn)物,但目標(biāo)化合物經(jīng)過(guò)分離和提取只得到酰胺化產(chǎn)物.原因是整個(gè)反應(yīng)在弱堿性環(huán)境中進(jìn)行,酚羥基在堿性條件下發(fā)生解離形成了氧負(fù)離子,由于氧負(fù)離子上的孤對(duì)電子和苯環(huán)間強(qiáng)的p-π共軛效應(yīng)使得N原子電子云密度提高,增強(qiáng)了氨基的親核性,從而有助于氨基進(jìn)攻羰基碳,有利于酰胺的形成.
2.1.6 反應(yīng)后處理
反應(yīng)后處理中,用到水、飽和食鹽水等進(jìn)行洗滌,需要在低溫下進(jìn)行.先將配好的洗滌液放置于冰箱內(nèi)冷凍一段時(shí)間,在操作時(shí)停留時(shí)間要盡可能的短,否則在有機(jī)相和水相之間會(huì)有一層白色絮狀沉淀生成,所產(chǎn)生的白色絮狀物是產(chǎn)品的水解產(chǎn)物和未反應(yīng)的N,N′-二環(huán)己基碳酰亞胺(DCC)吸水生成的N,N′-二環(huán)己基脲(DCU).其原因可能是用作后處理的有機(jī)溶劑與洗滌劑接觸時(shí)發(fā)生反應(yīng)而迅速放熱,從而導(dǎo)致有副產(chǎn)物的生成,大大降低產(chǎn)率.
2.2 結(jié)構(gòu)表征實(shí)例
以(E)-3-(3-甲氧基-4-羥基苯基)-N-(2-羥基苯基)丙烯酰胺7為例,對(duì)其結(jié)構(gòu)進(jìn)行波譜解析.
化合物7的氫譜分析:1H NMR (400 MHz, DMSO-d6) δ (ppm) 3.83處峰面積為3的單峰可歸屬為3位甲氧基的氫;δ 5.59處峰面積為1的單峰可歸屬為與N原子相連的苯環(huán)上2'位羥基的氫;δ 6.78處峰面積為1的耦合常數(shù)為7.1,1.9 Hz的雙峰是6位的氫;δ 6.81處峰面積為1的耦合常數(shù)為7.1 Hz的雙峰是5位的氫;δ 7.69處峰面積為1的耦合常數(shù)為15.7 Hz的雙峰是α位的氫,δ 6.88處峰面積為1的耦合常數(shù)為15.7 Hz的雙峰是β位的氫,該耦合常數(shù)證明了構(gòu)建的烯鍵為反式構(gòu)型;δ6.93處峰面積為1的耦合常數(shù)為8.1,1.8 Hz的雙峰是與N原子相連的苯環(huán)上3'位的氫;δ 7.06處峰面積為1的耦合常數(shù)為8.1 Hz的雙峰是與N原子相連的苯環(huán)上5'位的氫;δ 7.23處峰面積為1的單峰可歸屬為2位的氫;δ 7.46處峰面積為1的耦合常數(shù)為8.5 Hz的雙峰是與N原子相連的苯環(huán)上4'位的氫;δ 9.37處峰面積為1的單峰是氮原子的氫,因?yàn)轸驶偷拥奈娮幼饔檬蛊錃浠瘜W(xué)位移向低場(chǎng)移動(dòng).δ 9.36處的單峰是4位羥基氫.
化合物7的碳譜分析:13C NMR (101 MHz, DMSO-d6) δ (ppm) 60.61可歸屬為3位甲基的碳;δ 120.70,124.19,126.64,129.56,131.42,152.96歸屬為與氮原子相連的苯環(huán)上的6個(gè)碳;δ 115.77,120.85,127.39,131.85,152.58,153.73歸屬為另一個(gè)苯環(huán)上的6個(gè)碳;δ 123.89歸屬為β位的碳;δ 145.90歸屬為α位的碳;與氧原子、雙鍵連接的碳原子,化學(xué)位移比較大,δ 169.61歸屬為羰基的碳.
化合物7的IR圖譜解析:3 327 cm-1和3 275 cm-1處分別歸屬于O-H伸縮振動(dòng)吸收峰和N-H伸縮振動(dòng)峰;2 926 cm-1和2 840 cm-1處為C-H伸縮振動(dòng)吸收峰;1 658 cm-1可歸屬于C=O伸縮振動(dòng)吸收峰,1 622 cm-1,1 590 cm-1,1 507 cm-1,1 424 cm-1為苯環(huán)骨架C=C吸收峰;1 260 cm-1處歸屬于甲氧基C-O-C伸縮振動(dòng)吸收峰;818 cm-1處歸屬于苯環(huán)上C-H面外彎曲振動(dòng)吸收峰.
3 結(jié) 論
本文以廉價(jià)易得的香蘭素為原料,經(jīng)克腦文蓋爾(Knoevenagel)縮合反應(yīng)得到阿魏酸(1),阿魏酸(1)經(jīng)DCC/DMAP催化脫水合成阿魏酸酰胺類化合物2-9.對(duì)阿魏酸和8種胺的酰胺化反應(yīng)條件進(jìn)行了優(yōu)化.所合成的8種阿魏酸酰胺類化合物中,化合物7和化合物8是未見(jiàn)文獻(xiàn)報(bào)道的新化合物.該阿魏酸酰胺類化合物合成方法原料易得、工藝簡(jiǎn)便、收率較高,具有較大的應(yīng)用價(jià)值.我們正在研究阿魏酸酰胺類化合物的自由基仿生氧化偶合反應(yīng),以期得到生物活性更好的天然苯并呋喃類新木脂素化合物.
參考文獻(xiàn)
[1] OGIWARA T, SATOH K, KADOMA Y, et al. Radical scavenging activity and cytotoxicity of ferulic acid[J]. Anticancer Research,2002,22(5):2711-2717.
[2] KAWABATA K, YAMAMOTO T, HARA A, et al. Modifying effects of ferulic acid on azoxymethane-induced colon carcinogenesis in F344 rats[J]. Cancer Letters, 2000, 157(1):15-21.
[3] CHIANG L C, NG L T, CHIANG W, et al. Immunomodulatory activities of flavonoids, monoterpenoids, triterpenoids, iridoid glycosides and phenolic compounds of Plantago species[J]. Planta Medica,2003,69(7):600.
[4] 袁卓, 張軍平, 楊萃. 阿魏酸對(duì)血管內(nèi)皮細(xì)胞生長(zhǎng)因子誘導(dǎo)的血管平滑肌細(xì)胞遷移的影響[J]. 中國(guó)中西醫(yī)結(jié)合雜志,2012,32(2):229-233.
YUAN Z, ZHANG J P, YANG C. Study on the effects of ferulic acid on the vascular smooth muscle cellmigration in vitro[J]. Chinese Journal of Integrated Traditional and Western Medicine,2012,32(2):229-233.(In Chinese)
[5] LEE C, KIM J, LEE H, et al. Two new constituents of Isodon excisus and their evaluation in an apoptosis inhibition assay[J]. Journal of Natural Products,2001,64(5):659.
[6] NESTERENKO V, PUTT K S, HERGENROTHER P J. Identification from a combinatorial library of a small molecule that selectively induces apoptosis in cancer cells[J]. Journal of the American Chemical Society,2003,125(125):14672-14673.
[7] OKOMBI S, RIVAL D, BONNET S, et al. Analogues of N -hydroxycinnamoylphenalkylamides as inhibitors of human melanocyte-tyrosinase[J]. Bioorganic & Medicinal Chemistry Letters,2006,16(8):2252-2255.
[8] JUNG Y S, KANG T S, YOON J H, et al. Synthesis and evaluation of 4-hydroxyphenylacetic acid amides and 4-hydroxycinnamamides as antioxidants[J]. Bioorganic & Medicinal Chemistry Letters,2003,34(6): 2599-2602.
[9] CARMIGNANI M, VOLPE A R, BOTTA B, et al. Novel hypotensive agents from Verbesina caracasana. 8. Synthesis and pharmacology of (3,4-dimethoxycinnamoyl)-N(1)-agmatine and synthetic analogues[J]. Journal of Medicinal Chemistry, 2001,44(18):2950-2958.
[10]LIU H, LIN L, GAO X, et al. Novel ferulic amide derivatives with tertiary amine side chain as acetylcholinesterase and butyrylcholinesterase inhibitors: The influence of carbon spacer length, alkylamine and aromatic group[J]. European Journal of Medicinal Chemistry,2016, 126:810.
[11]KAZMIERSKI W, BIFULCO N, YANG H, et al. Recent progress in discovery of small-molecule CCR5 chemokine receptor ligands as HIV-1 inhibitors[J]. Bioorganic & Medicinal Chemistry,2003,11(13):2663-2676.
[12]LIN L C, SHEN C C, SHEN Y C , et al. Anti-inflammatory Neolignans from Piper kadsura[J]. Journal of Natural Products,2006,69(5):842-844.