国产一卡2卡三卡4卡麻豆_了解最新日韩草逼视频_h片在线播放一区_国产激情影视在线_好了av四色综合无码久久_欧美黑白双插OOR720P_日本精品中文字幕在线_秋霞午夜手机影院_亚洲国产一区二区3da毛片_欧美杂交深喉video中文字幕

重慶渝偲醫藥科技有限公司
初級會員 | 第3年

19923757617

渝偲醫藥關于:三苯甲基保護的胺基的脫保護介紹

時間:2022/11/18閱讀:297
分享:

Trt容易用酸脫去,如用HOAc50%(或75%HOAc的水溶液在30或回流數分鐘順利除去。這時N-BocO-But可以穩定不動。其他如HCl/MeOHHCl/CHCl3HBr/HOAcTFA都能很方便的脫去Trt,用HCl/MeOH處理Trt-Lys(Trt)OCH3可以得到Lys(Trt)OCH3,說明側鏈上的Trt比α-Trt 對酸更穩定一些Cys(Trt)His(Trt)Try(Trt)等的側鏈上的N-TrtNα-Trt 對酸穩定,因此可以采用適當的酸解條件選擇性脫去Nα-Trt而保留側鏈上的N-Trt

Trt對酸的敏感程度還隨所用的酸的不同而異,例如Trt對醋酸比較敏感,在80%的醋酸中,Trt的脫除速度大約比Bpoc7倍,比Boc21000倍,因而可以在BocMoz存在下選擇性地脫去Trt。但如用0.1MHBr/HOAc為試劑,Trt脫去速度反而慢于BocMoz

Trt也能被催化氫解脫去,但脫去速度比O-芐基和N-Cbz要慢得多。根據所用試劑和脫去方法得不同,Trt被分解所形成的產物也不同(見下式)。

一、TFA脫去三苯甲基示例

M. Firouz Mohd Mustapa,RichardHarris,Nives Bulic-Subanovic et al., J. Org. Chem.2003,21, 8185; S. Vinay, M. Mizio etal., Tetrahedron, 2002, 44, 9101

Compound 1(3.5 g, 4.6 mmol) was treated with a 5%solution of trifluoroacetic acid (1.4 mL, 18 mmol, 4 equiv) in CHCl3(27 mL) under inert conditions for 4 h. The resultingsolution was diluted with CHCl3(200 mL) andwashed with sodium hydrogen carbonate (5% aq w/v, 2 × 75 mL) and water (2 × 50mL). The solvent was removed in vacuo. The material was then redissolved in CHCl3(20 mL) and MeOH (20 mL), and the solvents were againremoved in vacuo to yield compound 2(2.1 g, 87%) as a pale yellowliquid.

二、 TFA-TIS脫去三苯甲基示例

Swall, Vinay; Matteuccl et al., Tetrahedron, 2002, 58(44), 9101-9110

Compound 1(2.0 g, 2.71 mmol) was stirred with TFA(4.9mL), CH2Cl2 (4.9mL) and TIS (0.2 mL) for 1 h. Solventwas removed in vacuo and the residue purified by column chromatography (SiO2, MeOH/CHCl3, 1:9 v:v) toafford compound 2(1.16 g,91%) as a white solid.

三、TFA-Et3SiH脫去三苯甲基示例

Pickersgill, I.Fraser; Rapoport, Henry; J. Org. Chem., 2000,65(13),4048-4057

To a stirred solution of compound 1(3.34 g, 3.82 mmol) and triethylsilane (0.64 mL, 4.01mmol) in CH2Cl2(16 mL) cooled to 0 °C was added dropwise TFA (16 mL). Theresultant colorless solution was allowed to warm to rt, with stirring continuedfor 1 h. The solvents were evaporated, the residue was triturated with hexanes(5 x 50 mL), the hexane extracts were discarded, and the oily residue waspartitioned between CHCl3/IPA (250 mL, 3/1) and 1 M NaOH (precooled to 0 °C,100 mL). The aqueous phase was extracted with further portions of CHCl3/IPA (2 x 200mL, 3/1), and the combined organic phase was dried, filtered, and evaporated togive compound 2(2.04 g, 100% crude yield) as a pale yellowoil.

4.1.2.4 HOAc脫去三苯甲基示例

Vago, Istvan; Kalaus, Groergy et al., Heterocycles,2001, 55(5), 873-880

0.85 g(2 mmol) of compound wasdissolved in the mixture of 20 mL of acetic acid and 0.5 mL of water. The solutionwas heated under argon at 60 oC for 1 h, and then allowed to cool to rt. Theresulted dark solution was diluted with 200 mL of water; the triphenylmethanolwas removed by extraction with ether. The pH of the watery phase was adjustedto a value of 8 with sodium carbonate solution, extracted with dichloromethane;the extract was dried with magnesium sulfate, evaporated to dryness in vacuumtogive, compound 2(0.24 g,64 %) as unstable brown oil.

4.1.2.5 TBSBoc官能團存在下用BF3-HOAc脫去三苯甲基示例

Pickersgill, I, Fraser; Rapoport, Henry; J. Org. Chem., 2000, 65(14),4048-4057

To a solution of 32 (2.67 g, 3.98 mmol) in CH2Cl2(27 mL) cooled to 0 °C were added glacial acetic acid (6.7 mL)and BF3.Et2O (0.529 mL, 4.17 mmol) dropwise, and the mixture wasstirred at 0 °C for 2 h.Cold (0 °C) 1 M NaOH (160 mL) was added and the mixturepartioned between CHCl3/IPA (320 mL, 3/1) and cold (0 °C) 1 M NaOH (66 mL), followed by extraction with further portions ofCHCl3/IPA (2 x 160 mL, 3/1). The combined organic phase wasdried, filtered, and evaporated to a residue which was chromatographed (CH2Cl2/MeOH,19/1 to 9/1) to give 33 (1.50 g,88%) as a colorless oil: [α]22D+3.1 (c = 1.0,CHCl3).

注:本文系本站編輯轉載,轉載目的在于傳遞更多信息,并不代表本網贊同其觀點和對其真實性負責。如涉及作品內容、版權和其它問題,請在30日內與本站聯系,我們將在第一時間刪除內容![聲明]本站文章版權歸原作者所有 內容為作者個人觀點 本站只提供參考并不構成任何投資及應用建議。本站擁有對此聲明的最終解釋權

會員登錄

×

請輸入賬號

請輸入密碼

=

請輸驗證碼

收藏該商鋪

X
該信息已收藏!
標簽:
保存成功

(空格分隔,最多3個,單個標簽最多10個字符)

常用:

提示

X
您的留言已提交成功!我們將在第一時間回復您~
撥打電話
在線留言
主站蜘蛛池模板: 孝义市| 乡城县| 酒泉市| 南康市| 承德市| 得荣县| 东乌珠穆沁旗| 神木县| 丘北县| 崇信县| 阿尔山市| 博客| 玉树县| 嘉定区| 海宁市| 萝北县| 襄汾县| 江永县| 蓬安县| 涿鹿县| 饶平县| 通化市| 罗甸县| 大冶市| 孟州市| 阳曲县| 阜阳市| 天水市| 大石桥市| 察雅县| 淮南市| 乐陵市| 阿拉善左旗| 华容县| 赣州市| 溧阳市| 荣昌县| 马关县| 治县。| 贵南县| 安新县|