All Blogs | Help | Support | About
x This LabTrove instance has just been upgraded to 2.3, to see what new check out the documentation, http://www.labtrove.org/documentation/
1st October 2014 @ 11:06

Palladium catalysed coupling of JU 26 and JU 29-1 (boronic ester) to form the fluoroalkene.  

Github issue:

Literature ref:

Reaction Scheme

Procedure

Started 4:30pm

JU 26 (~20-30 mg, flask was washed out, 0.1-0.15 mmol, 1 equiv), JU 29-1 (85 mg, 0.3 mmol, 2 equiv), potassium carbonate (104 mg, 0.75 mmol, 6 equiv) were stirred into toluene (3.75 mL), ethanol (0.75 mL) and water (0.75 mL). 2 balloons of argon were bubbled through to remove oxygen. 1,4-Bis(diphenylphosphino)butane-palladium(II) chloride (12 mg, 0.02 mmol, 0.2 equiv) was added and the mixture heated at reflux overnight. 

 

HIRAC

HIRAC JU 31-1.pdf

InChI strings

InChI=1S/C11H15BBrNO2/c1-10(2)11(3,4)16-12(15-10)8-6-5-7-9(13)14-8/h5-7H,1-4H3

and

InChI=1S/C8H6BrF/c9-8(10)6-7-4-2-1-3-5-7/h1-6H/b8-6-

to

InChI=1S/C13H9BrFN/c14-13-8-4-7-12(16-13)11(15)9-10-5-2-1-3-6-10/h1-9H/b11-9-

SMILES

BrC1=CC=CC(B2OC(C)(C)C(C)(C)O2)=N1

and

BrC(F)=[S=I]CC[4]=CC=CC=C@5

to

BrC1=CC=CC(/C(F)=C/C2=CC=CC=C2)=N1

Attached Files
30th September 2014 @ 02:13

See Repeat synthesis of 5-chloro-[1,2,4]triazolo[4,3-a]pyrazine (TM 37-14) for method.

scheme

hydrazinylpyrazine (from Preparation of 2-hydrazinylpyrazine (TM 62-1): 1.5 g, 13.6 mmol) was dissolved in toluene (15 mL), triethyl orthoformate (3.4 ml, 20.4 mmol, 1.5 eq) and TsOH (235 mg, 1.36 mmol, 10 mol %) added, and the reaction mixture refluxed (bath temp 110 oC) for 24 h. Solvents removed under reduced pressure, and purified by FCC (EtOAc, hexanes).

Attached Files
29th September 2014 @ 05:06

Trialling an aromatic Finkelstein reaction, to give an iodo TP hopefully more suitable for Pd-catalysed carbonylative couplings. Conditions taken from 10.1021/ol048987n.

scheme

 

5-chloro-[1,2,4]triazolo[4,3-a]pyrazine (from Repeat synthesis of 5-chloro-[1,2,4]triazolo[4,3-a]pyrazine (TM 37-14): 155 mg, 1 mmol), sodium iodide (3.0 g, 20 mmol, 20 eq), and TFA (0.38 mL, 5 mmol, 5 eq) were stirred in butanone (20 mL) at –45 °C (dry ice in 60:40 ethylene glycol:ethanol bath) for 5 h. The product was added to saturacted NaHCO3 solution (10 mL), extracted with DCM (3 x 25 mL), and the organic layers washed with water (5 mL) and brine (5 mL) before being concentrated under reduced pressure to give 260 mg of crude product as a tacky brown solid.

Attached Files
29th September 2014 @ 02:33

scheme

See Resynthesis of 2-chloro-6-hydrazinylpyrazine (TM 34-3) for method.

2-chloropyrazine (3 g, 26.2 mmol) was dissolved in EtOH (15 mL), and hydrazine hydrate (2.6 mL, 52 mmol, 2 eq) added. The mixture was refluxed for ?? h.

 

HIRAC:

62-1 hirac.pdf

Linked Posts
Attached Files
25th September 2014 @ 07:20

Reaction performed in parallel to TM 60-1.

scheme

A 21 mL sample vial was oven dried, then allowed to cool under vacuum (using a teflon vial adapter fitted with a septum). A stirbar, 3 Å powdered molecular sieves (stored in an oven, then microwave activated; 150 mg), potassium carbonate (also stored in oven; 207 mg, 1.5 mmol), palladium acetate (5 mg, 2 mol %), and dcpp • 2HBF4 (25 mg, 4 mol %) were added to the vial, which was then evacuated for several minutes (avoiding disturbance of the finely powdered solid contents). Two nested balloons attached to a short section of tubing fitted with a stopcock were flushed three times with carbon monoxide, then filled (around 150 mL), and attached to a three-way valve connected to the vial and vacuum. The vial was evacuated and refilled with CO three time, then DMF (dried over 4 Å sieves, degassed by freeze-thawing, then stored over 4 Å sieves under argon; 1 mL), 3-chloropyridine (114 mg, 1 mmol, 0.95 uL), and ethanol (0.3 mL, ~5 mmol, 5 eq)) added by syringe.

The reaction mixture was heated to 110 °C for 5 hours, then diluted with EtOAc (~ 15 mL), filtered through a plug of celite, rinsed with more EtOAc (~25 mL), then concentrated on celite before purification by automatic column chromatography (silica, hexanes:EtOAc) to give one fraction.

Pure TM 61-1 was obtained as a white solid (80 mg, 53 %).

NMR:

1H (CDCl3, 500 MHz)

Ethyl picolinate 1H CDCl3 500 MHz.pdf

13C (CDCl3, 500 MHz)

Ethyl picolinate 13C CDCl3 500 MHz.pdf

carbonylative screening Ethyl pyridinyl.zip

Attached Files