黃國(guó)保,雷 茜,黃勝梅,謝厚知,潘英明,王恒山
(廣西師范大學(xué)化學(xué)化工學(xué)院藥用資源化學(xué)與藥物分子工程重點(diǎn)實(shí)驗(yàn)室,廣西桂林 541004)
松香酸具有多個(gè)構(gòu)型穩(wěn)定且易改造的手性官能團(tuán),其衍生物已應(yīng)用于催化[1,2]和手性分離[3,4]。近年來(lái)本課題組在松香基手性分離試劑的研制與開(kāi)發(fā)利用方面都取得了較大進(jìn)展[5~8]。最近我們發(fā)現(xiàn)松香異構(gòu)化產(chǎn)物與α-(9-蒽基)-α-甲氧基乙酸和S-1-萘基甲氧基乙酸有很相似的手性骨架,因此該類松香異構(gòu)化產(chǎn)物有很強(qiáng)的磁各向異性,有望提高手性選擇的性能,預(yù)期其可能具有更高的NMR識(shí)別能力。
本文以脫氫松香酸(1)為原料,通過(guò)酯化、溴代、異構(gòu)化、水解等反應(yīng)合成了磁各向異性更強(qiáng)的6-溴-7-異丙基-1,10-二甲基-1,2,3,4-四氫蒽-1-羧酸(8,Scheme 1),其結(jié)構(gòu)經(jīng)1H NMR,13C NMR,MS和元素分析表征。8為新化合物。
Scheme 1
WRS-1A型數(shù)字熔點(diǎn)儀(溫度未校正);Perkin Elmer Model 341型旋光儀;AVANCE AV 500型超導(dǎo)核磁共振儀(CDCl3為溶劑,TMS為內(nèi)標(biāo));BRUKER ESQUIRE HCT型質(zhì)譜儀;Carlo Erba 1106型元素分析儀。
脫氫松香酸甲酯(2)[9],7-氧基脫氫松香酸甲酯 (3)[10]和 12-溴-7-羰基脫氫松香酸甲酯(4)[11]按文獻(xiàn)方法合成;NBS,安耐吉化學(xué)試劑有限公司;CDCl3,硼氫化鈉和氫氧化鋰,百靈威化學(xué)試劑有限公司;工業(yè)一級(jí)松香和歧化松香,梧州松脂廠;其余所用試劑均為分析純。
(1)12-溴-7-羰基-5,8,11,13-松香四烯-18-羧酸甲酯(5)的合成
在反應(yīng)瓶中加入 4 0.6 g(1.5 mmol),二氧化硒3 g(27 mmol),冰醋酸13 mL 和水 6.5 mL,攪拌至均勻,回流(135℃)反應(yīng)10 h。冷卻至室溫,旋蒸脫溶,加入乙醚30 mL,過(guò)濾,濾液依次用5%碳酸鈉溶液(20 mL)和飽和食鹽水(20 mL)洗滌,無(wú)水硫酸鈉干燥,濃縮后經(jīng)硅膠柱層析[洗脫劑:A=V(石油醚)∶V(乙酸乙酯)=9∶1]純化,甲醇重結(jié)晶得無(wú)色晶體 5 0.5 g,收率82.7%,m.p.76℃ ~78 ℃;1H NMR δ:1.27 ~1.32(dd,J=7.0 Hz,6H,16,17-H),1.56(s,3H,20-H),1.66(s,3H,19-H),1.94 ~ 2.00(m,2H,2-H),2.21 ~2.48(m,2H,3-H),2.93 ~2.96(m,2H,4-H),3.35 ~3.41(m,1H,15-H),3.74(s,3H,21-H),6.14(s,1H,8-H),7.71(s,1H,11-H),8.03(s,1H,14-H)。
(2)6-溴-7-異丙基-1,10-二甲基-1,2,3,4-四氫蒽-1-羧酸甲酯(7)的合成
在反應(yīng)瓶中加入 5 0.7 g(1.7 mmol),七水合三氯化鈰0.8 g(3 mmol),甲醇3.5 mL和四氫呋喃3.5 mL,攪拌至完全溶解;加入硼氫化鈉80 mg(2 mmol),于室溫反應(yīng)15 min。加入乙醚20 mL,用飽和食鹽水洗滌,無(wú)水硫酸鈉干燥,減壓蒸除溶劑得 12-溴-7-羥基-5,8,11,13-松香四烯-18-羧酸甲酯(6)粗品。加入無(wú)水二氯甲烷30 mL,冰浴下加入三氟化硼(0.68 g)的乙醚(1.2 mL)溶液,攪拌下于室溫反應(yīng)1 h。加入乙醚50 mL,依次用稀鹽酸(30 mL)和飽和食鹽水(30 mL)洗滌,無(wú)水硫酸鈉干燥,旋蒸脫溶后經(jīng)硅膠柱層析(洗脫劑:A=10∶1)反復(fù)純化得黃色膏狀物7 0.51 g,兩步總產(chǎn)率 76.2%,m.p.102 ℃ ~103 ℃,[α]20D-23 °(c0.50,CHCl3);1H NMR δ:1.36 ~1.37(s,6H,16,17-H),1.66(s,3H,19-H),1.69(s,3H,20-H),1.90 ~2.20(m,4H,2,3-H),2.93 ~2.96(m,2H,4-H),3.45 ~3.51(m,1H,15-H),3.74(s,3H,21-H),7.56(s,1H,9-H),7.60(s,1H,8-H),8.25(s,1H,5-H)。
(3)8的合成
在反應(yīng)瓶中加入7 0.8 g(2 mmol),混合溶劑[V(甲醇)∶V(四氫呋喃)∶V(水)=2 ∶2 ∶1]10 mL,攪拌使其完全溶解;加入LiOH·H2O 0.42 g,于室溫反應(yīng)10 h。過(guò)濾,濾液用10%NaH2PO4調(diào)至pH 4,用二氯甲烷(3×10 mL)萃取,合并萃取液,用飽和食鹽水洗滌,無(wú)水硫酸鈉干燥,旋蒸脫溶后經(jīng)硅膠柱層析(洗脫劑:A=30∶1)純化得白色固體 8 0.3 g,收率 65.2%,m.p.177.5 ℃ ~178.0 ℃,[α]20D- 16.9 °(c0.50,EtOH);1H NMR δ:1.28(s,3H,17-H),1.66(s,3H,19-H),1.69(s,3H,16-H),1.80 ~ 1.82(m,2H,2-H),1.92(m,2H,3-H),2.93~2.96(m,2H,4-H),3.43~3.46(m,1H,15-H),7.62(s,1H,9-H),7.64(s,1H,8-H),8.23(s,1H,5-H);13C NMR δ:14.85(C20),19.73(C3),23.33(C16,17),27.95(C19),28.25(C4),32.75(C15),34.68(C2),46.83(C1),122.85(C6),124.91(C9),126.10(C5),127.44(C13),130.23(C8),131.03(C10),131.25(C14),133.61(C7),139.84(C12),143.13(C1),178.50(C18);IR ν:3 436,2 961,2 868,1 698,1 464,1 401 cm-1;MSm/z:373{[M -H]+};Anal.calcd for C20H23O2Br:C 64.01,H 6.18;found C 64.15,H 6.06。
8的1H NMR分析結(jié)果與其分子式(C20H23O2Br)一致:7.0~9.0處出現(xiàn)芳環(huán)上三個(gè)質(zhì)子單峰,表明質(zhì)子沒(méi)有偶合;2.50處出現(xiàn)三個(gè)質(zhì)子單峰,表明甲基連接在芳環(huán)上;異丙基的特征峰也很明顯。在8的 IR譜中,3 436 cm-1處為羧基中OH 的伸縮振動(dòng)峰,2 868 cm-1~2 961 cm-1為芳環(huán)C-H的伸縮振動(dòng)吸收峰,1 698 cm-1處為羧基中 C=O的伸縮振動(dòng)吸收峰,1 400 cm-1~1 464 cm-1為芳環(huán)骨架振動(dòng)吸收峰。
綜上分析結(jié)果表明8為預(yù)期產(chǎn)物6-溴-7-異丙基-1,10-二甲基-1,2,3,4-四氫蒽-1-羧酸。
[1]Jiang X,Zhang Y,Wang R,et al.Doubly stereocontrolled asymmetric aza-Henry reaction with in situ generation ofN-Boc-imines catalyzed by novel rosin-derived amine thiourea catalysts[J].Adv Synth Catal,2009,(351):2096 -2100.
[2]Jiang X,Zhang G,F(xiàn)u D,et al.Direct organocatalytic asymmetric aldol reaction of α-isothiocyanato imides to α-ketoesters under low ligand loading:A doubly stereocontrolled approach to cyclic thiocarbamates bearing chiral quaternary stereocenters[J].Org Lett,2010,12:1544-1547.
[3]Ye F G,Zhao S L.Maleopimaric acid anhydridebonded silica monolith as chiral stationary phase for separations of phenylthiocarbamyl amino acids by CEC[J].Electrophoresis,2010,31:1488 - 1429.
[4]姚貴陽(yáng),韋京辰,戴偉龍,等.馬來(lái)海松酸三甲酯區(qū)域選擇性格氏加成反應(yīng)研究[J].Chin J Org Chem,2013,33:138 -142.
[5]Zhao S L,Wang H S,Pan Y M,et al.3-[(3-Dehydroabietamidopropyl)dimethylammonio]-1-propanesulfonate as a new type of chiral surfactant for enantiomer separation in micellar electrokinetic chromatography[J].J Chromatogr A,2007,(1145):246 -249.
[6]Zhao S L,Zhang R C,Liu Y,et al.Degradingdehydroabietylisothiocyanate as a chiral derivatizing reagent for enantiomeric separations by capillary electrophoresis[J].Electrophoresis,2006,27:3428 -3433.
[7]Wang H S,Zhao S L,Pan Y M.Synthesis and application of dehydroabietylisothiocyante as a new chiral derivatizing agent for the enantiomeric separation of chiral compounds by capillary electrophoretic[J].Anal Chim Acta,2006,(560):64 -68.
[8]Wang H S,Pan Y M,Wu Q.Synthesis and enantiomeric recognition ability of 22-crown-6 ethers derived from rosin acid and BINOL[J].Tetrahedron:Asymmetry,2011,22:381 -386.
[9]Fieser L F.Concerning dehydroabietic acid and the structure of pine resin acids[J].Journal of the American Chemical Society,1938,60(1):159 -170.
[10]Wenkert E,Jackson B G.Rearrangements and oxidations of tricarbocyclic diterpenes[J].Journal of the American Chemical Society,1958,80(1):211 -217.
[11]Yoh-ichi M,Yoshihisa I,Satoru Y,et al.Synthesis of 12-deoxyroyleanone,cryptoquinone,11,14-dihydroxy-8,11,13-abietatrien-7-one,and related derivatives from dehydroabietic acid[J].Chem Pharm Bull,1974,22:1547 -1554.