ChemicalBook CAS DataBase List 3-(4,4,5,5-TETRAMETHYL-1,3,2-DIOXABOROLAN-2-YL)PYRAZOLO[1,5-A]PYRIDINE

3-(4,4,5,5-TETRAMETHYL-1,3,2-DIOXABOROLAN-2-YL)PYRAZOLO[1,5-A]PYRIDINE synthesis

7synthesis methods

Product Name:3-(4,4,5,5-TETRAMETHYL-1,3,2-DIOXABOROLAN-2-YL)PYRAZOLO[1,5-A]PYRIDINE
CAS Number:1207557-48-9
Molecular formula:C13H17BN2O2
Molecular Weight:244.1

61676-62-8 Synthesis

2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane

61676-62-8
319 suppliers
$10.00/5g

19363-99-6
46 suppliers
$464.00/100mg

3-(4,4,5,5-TETRAMETHYL-1,3,2-DIOXABOROLAN-2-YL)PYRAZOLO[1,5-A]PYRIDINE

1207557-48-9
68 suppliers
$65.00/10mg

Yield:1207557-48-9 90%

Reaction Conditions:

with TurboGrignard in tetrahydrofuran at 5 - 10; for 2 h;Inert atmosphere;

Steps:

4.1.3.1. Using isopropylmagnesium lithium chloride
Isopropylmagnesium lithium chloride (43.5 mL, 49.99 mmol, 1.15 M solution in THF) was added dropwise to a stirred solution of 3-iodopyrazolo[1,5-a]pyridine (11, 12.2 g, 49.99 mmol) and 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (15.30 mL, 74.99 mmol) in THF (120 mL) at 5 °C (internal temperature kept below 10 °C), over a period of 10 min, under nitrogen. The resulting solution was stirred at 5 °C for 2 h and then concentrated under reduced pressure. The residue was diluted with DCM (50 mL), the suspension was filtered through a pad of silica, eluting with EtOAc (1000 mL) and evaporated to afford crude product, which was purified by flash chromatography (0-20% EtOAc/heptane) to give the title compound (10, 10.96 g, 90%) as a white solid; δ_H (400 MHz, CDCl₃): 1.36 (12H, s, 2×Me₂CO), 6.81 (1H, td, J 7, 1 Hz, ArH-6), 7.21 (1H, ddd, J 9, 7, 1 Hz, ArH-5), 7.96 (1H, dt, J 9, 1 Hz, ArH-4), 8.23 (1H, s, ArH-2), 8.51 (1H, dt, J 7, 1 Hz, ArH-7); δ_C(101 MHz, CDCl₃): 24.94 (4 CH₃), 83.12 (2C), 112.47, 120.09, 124.77, 128.82, 145.63, 148.77, C-B not seen; m/z (ES⁺) 245 (100, MH⁺); HRMS (ESI): MH⁺, found 245.14558. C₁₃H₁₈BN₂O₂ requires 245.14558.

References:

Bethel, Paul A.;Campbell, Andrew D.;Goldberg, Frederick W.;Kemmitt, Paul D.;Lamont, Gillian M.;Suleman, Abid [Tetrahedron,2012,vol. 68,# 27-28,p. 5434 - 5444] Location in patent:experimental part

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5910-12-3 Synthesis