New downstream synthetic route of 6-Bromopyrazolo[1,5-a]pyrimidine

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route,705263-10-1, its application will become more common.

Application of 705263-10-1, In the chemical reaction process,reaction time,type of solvent,can easily affect the result of the reaction, thereby determining the yield and properties of the reaction product.An updated downstream synthesis route of 705263-10-1 as follows.

Preparative Example 14 Step 1 : 6-(4,4,5,5-tetramethyl-l,3,2-dioxaborolan-2-yl)pyrazolo[l,5-a]pyrimidine To a solution of 6-bromopyrazolo[l,5-a]pyrimidine (1.5 g, 7.57 mmol) in 1,4-dioxane (20 mL) were added 4,4,4′,4′,5,5,5′,5′-octamethyl-2,2′-bi(l,3,2-dioxaborolane) (2.12 g, 8.33 mmol), potassium acetate (1.48 g, 15.14 mmol) and l,l’-bis(diphenylphosphino)ferrocene-palladium(II)dichloride (553 mg, 0.76 mmol). The reaction mixture was purged with nitrogen for 2 min and heated to 100 C for 4 h and subsequently concentrated to dryness in vacuo. The resulting viscous mass was diluted with water and extracted with ethyl acetate (2 x 50 mL). The combined organic layers were dried over sodium sulfate and concentrated to dryness in vacuo. The resulting residue was purified by column chromatography (silica gel, 100-200 mesh, 30% ethyl acetate in hexane) affording 6-(4,4,5,5- tetramethyl-1 ,3,2-dioxaborolan-2-yl)pyrazolo[l ,5-a]pyrimidine (1.0 g, 54%): lU NMR (400 MHz, Chloroform-d) delta 8.99 (s, 1H), 8.69 (s, 1H), 8.15 (d, / = 2.4 Hz, 1H), 6.67 (d, J = 2.4 Hz, 1H), 1.42 (s, 12H).

These compound has a wide range of applications. It is believed that with the continuous development of the source of the synthetic route,705263-10-1, its application will become more common.

Reference:
Patent; F. HOFFMANN-LA ROCHE AG; GENENTECH, INC.; ESTRADA, Anthony; HUESTIS, Malcolm; KELLAR, Terry; PATEL, Snahel; SHORE, Daniel; SIU, Michael; (260 pag.)WO2016/142310; (2016); A1;,
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia