天堂网亚洲,天天操天天搞,91视频高清,菠萝蜜视频在线观看入口,美女视频性感美女视频,95丝袜美女视频国产,超高清美女视频图片

Welcome to chemicalbook!
Chinese English Japanese Germany Korea
400-158-6606
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 2-Amino-6-methylpyrazine
5521-56-2

2-Amino-6-methylpyrazine synthesis

11synthesis methods
-

Yield: 71%

Reaction Conditions:

with ammonia in water at 180; under 26252.6 Torr; for 8 h;sealed vessel;

Steps:

1.c
60ml) at O0C was added, diethylmalonate (2.1moleq) in THF (60ml) and 2,6- dichloropyrazine (2Og) in THF (40ml). The mixture was then heated to reflux for 18hrs before being allowed to cool and 2M Hydrochloric acid (100ml) added. The resulting two layers were separated and the THF layer partially concentrated under vacuum to give a solution containing 2-(6-chloro-pyrazin-2-yl)-malonic acid diethyl ester. This solution was EPO then cooled to 100C and 2M sodium hydroxide (328ml) added. After stirring for 24hrs the mixture was washed with methyl isobutyl ketone [MIBK] (200ml) and the organic layer discarded. The aqueous layer containing 2-(6-chloro-pyrazin-2-yl)-malonic acid was then added to 6M hydrochloric acid (135ml), maintaining a reaction temperature of 20-25°C to facilitate the decarboxylation.The resulting 6-chloro-pyrazin-2-yl-acetic acid partially precipitated from the mixture, but for ease of isolation was extracted into MIBK (130ml), dried using MgSO4, filtered and evaporated to give a yellow solid. The resulting crude solid 22.4g was then crystallised from methyl-t-butyl ether (MTBE) to give pure 6-chloro-pyrazin-2-yl-acetic acid , 15.4g 67% yield based on 2,6-dichlorpyrazine.The 6-chloro-pyrazin-2-yl-acetic acid (20.Og) was then treated with aqueous ammonia (120ml) in a sealed vessel at 180°C (35 bar) for 8hrs. The mixture was then cooled to 20°C and water (40ml) added, before being concentrated under vacuum to remove the ammonia. The product was extracted into ethyl acetate and the solution treated with charcoal, before being dried using MgSO4, filtered and evaporated to give 6-methyl-2-pyrazin-2-ylamine as a pale green solid 9.Og, 71% yield based on 6-chloro-pyrazin-2-yl-acetic acid. Analysis 2-(6-Chloro-pyrazin-2-yl)-malonic acid diethyl esterMS (EI +ve) 273/275 (M+H) IH NMR (CDCl3) :δ 8.7 (IHs), 8.5 (IHs), 4.9 (IHs), 4.2(2x2Hq), 1.2 (2x3Ht).6- Chloro-pyrazin-l-yl-acetic acidMS (EI +ve) 173/175 (M+H)IHNMR (CDCl3) :δ 8.55 (IH s), 8.50 (IH s); 3.9 (2Hs).6-Methyl-2-pyrazin-2-ylamine MS (GC/MS) : 100% RT 2.0mins, M+H = 110IHNMR (CDC13) : δ 7.8 (IHs), 7.8 (IHs), 4.4 (2H bs), 2.4 (3Hs). Mpt : 124-1250C

References:

ASTRAZENECA AB WO2007/35153, 2007, A1 Location in patent:Page/Page column 2; 4-5

2-Amino-6-methylpyrazine Related Search: