一二三四区视频,亚洲少妇熟女色,日本久热无码视频网,欧美国产日韩大尺度,亚洲a视频,久久少妇一区二区,日韩999无码视频,刺激久久久久久久,啊啊啊啊不要啊在线

Welcome to chemicalbook!
Chinese English Japanese Germany Korea
010-86108875
Try our best to find the right business for you.
Do not miss inquiry messages Please log in to view all inquiry messages.

Welcome back!

ChemicalBook CAS DataBase List 4-BROMO-3-HYDROXYPYRIDINE
161417-28-3

4-BROMO-3-HYDROXYPYRIDINE synthesis

2synthesis methods
Carbamic acid, N,N-diethyl-, 4-bromo-3-pyridinyl ester

98976-81-9

4-BROMO-3-HYDROXYPYRIDINE

161417-28-3

The general procedure for the synthesis of 4-bromo-3-hydroxypyridine from the compound (CAS: 98976-81-9) is as follows: to a solution of 4-bromo-3-pyridinyl diethylcarbamate (1.24 g, 4.50 mmol) in methanol (10 mL) was added methanolic solution of sodium methanolate (2.04 g, 9.40 mmol) at 20°C and the resulting mixture was refluxed for 1.5 hours. Upon completion of the reaction, methanol was removed by distillation under reduced pressure, ethyl acetate (15 mL) and water (1 mL) were added, and then the pH was adjusted to 9 with 20% aqueous sulfuric acid. the organic layer was separated, and the residue was washed with ethyl acetate (3 x 5 mL). The organic layers were combined, dried and concentrated with anhydrous sodium sulfate. The crude product was purified by rapid chromatography on silica gel, eluting sequentially with hexane/ethyl acetate (1:1 and 1:2) to give 691 mg (89% yield) of 4-bromo-3-hydroxypyridine.TLC Rf value was 0.38 (1:2 hexane/ethyl acetate). Mass spectra (DCI/NH3) m/e 174 (with 79 Br) and 176 (M+H)+ (with 81 Br).1H NMR (CDCl3, 300 MHz) δ: 8.43 (d, J=1.5 Hz, 1H, ArH), 8.02 (d, J=7.2 Hz, 1H, ArH), 7.54 (dd, J=7.2,1.5 Hz. 1H, ArH).

-

Yield:161417-28-3 89%

Reaction Conditions:

with sodium methylate in methanol

Steps:

20.c 20c.
20c. 4-bromo-3-pyridinol To a solution of 4bromo-3-pyridyl diethylcarbamate (1.24 g, 4.50 mmol) in methanol (10 mL) was added sodium methoxide in methanol (2.04 g, 9.40 mmol), and the resultant mixture was refluxed for 1.5 hours. After removal of MeOH, EtOAc (15 mL) and water (1 mL) were added, the pH was then adjusted to 9 using 20% H2 SO4. The organic layer was decanted, and the residue washed with EtOAc (3*5 mL). The combined organic layers were dried (Na2 SO4) and concentrated. The crude product was purified by flash chromatography on silica gel eluding with hexane/EtOAc (1:1 and 1:2) to provide 691 mg (89% yield) of the title compound. TLC Rf 0.38 (1:2 hexane/EtOAc). MS (DCI/NH3) m/e 174 with 79 Br and 176 (M+H)+ with 81 Br. 1 H NMR (CDCl3, 300 MHz) δ: 8.43 (d, J =1.5 Hz, 1H, ArH), 8.02 (d, J=7.2 Hz, 1H, ArH), 7.54 (dd, J=7.2, 1.5 Hz, 1H, ArH).

References:

Abbott Laboratories US5914328, 1999, A

FullText

4-BROMO-3-HYDROXYPYRIDINE Related Search:

郁南县| 鹿邑县| 上思县| 垦利县| 宝鸡市| 涪陵区| 梅州市| 西林县| 安泽县| 应用必备| 红桥区| 工布江达县| 潮安县| 威海市| 家居| 宝丰县| 依安县| 封开县| 大石桥市| 南川市| 镇坪县| 铁力市| 安远县| 惠来县| 英德市| 思茅市| 兴城市| 辽阳县| 巴林左旗| 镇赉县| 霸州市| 晋州市| 伊吾县| 普兰店市| 太谷县| 榆社县| 澄城县| 平果县| 乐清市| 玉门市| 会昌县|