5-Bromo-7-azaindole synthesis

Yield:183208-35-7 77.6%

Reaction Conditions:

Stage #1:5-bromo-1,3-dihydro-2H-pyrrolo[2,3-b]pyridin-2-one with hydrogenchloride;tin in ethanol;water at 40; for 2 h;
Stage #2: with copper(ll) bromide in chloroform at 60; for 2 h;Solvent;Temperature;Reagent/catalyst;

Steps:

2
In the 250 ml flask is sequentially added in 50 ml ethanol and 5 - bromo -1 - hydrogen pyrrolo [2,3 - the b] pyridine -2 - ketone (4.2g, 20 mmol), Sn powder (4.7 g, 40 mmol) and 5 mol/L hydrochloric acid (14 ml), 40 °C stirring for 2 hours, the reaction is completed, to remove the ethanol, add 50 ml of water residue is completely dissolved, saturatedNaHCO₃solution and to PH=8, and filtering the resulting solid, after drying, dissolved in 50 ml chloroform, addingCuBr₂(13.4 g, 60mmol), 60 °Cstirring for 2 hours, the reaction is completed, the end of the reaction, rotary evaporated to remove chloroform, adding 50 ml saturatedNaHCO₃solution, ethyl acetate (3 × 100 ml), the combined organic phase with water (50 ml) for washing and then the saturated salt water (50 ml) washing, anhydrousNa₂SO₄drying, filtering, the filtrate is concentrated to obtain 5 - bromo - 1H - pyrrolo [2,3 - the b] pyridine the crude product, the crude product is chloroform: hexane=2:1 (volume ratio) mixed solution recrystallize to get 3.1 g of pale yellow 5 - bromo - 1H - pyrrolo [2,3 - the b] pyridine pure product, yield 77.6%, melting point:176.8-177.3 °C,

References:

Heze University;Fan, Hongli;Li, Fenghai;Xu, Meiling;Guo, Qianqian CN106045995, 2016, A Location in patent:Paragraph 0022

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