Reaction #68482

Reaction equation

tert-butyl (6-chloro-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)methylcarbamate

triethyl(ethynyl)silane

Triethylamine

→

desired product

tert-butyl(6-(2-(triethylsilyl)ethynyl)-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)methylcarbamate

Solvents

Acetonitrile

Conditions

Workup

1. 1
   OtherA 1 L-round-bottomed flask flushed with argon
2. 2
   OtherThe first drops resulted in a change of color to light yellow/orange
3. 3
   workup.ADDITIONAt the end of the addition
4. 4
   workup.STIRRINGAfter stirring at 50° C. for one hour
5. 5
   Concentrationconcentrated in vacuo
6. 6
   OtherPurification by MPLC (ISCO, EtOAc/MeOH: 100/0 to 90/10)

Procedure

A 1 L-round-bottomed flask flushed with argon was charged with tert-butyl (6-chloro-[1,2,4]triazolo[4,3-b]pyridazin-3-yl)methylcarbamate (12.00 g, 42.3 mmol), Pd(dppf)Cl2—CH2Cl2 adduct (3.45 g, 4.23 mmol), copper iodide (2.01 g, 10.6 mmol) at room temperature. Acetonitrile (400 mL) was added followed by triethyl(ethynyl)silane (37.9 ml, 211 mmol). Upon stirring the reaction mixture turned dark red. Triethylamine (177 ml, 1269 mmol) was added via cannula over five minutes. The first drops resulted in a change of color to light yellow/orange. At the end of the addition, the reaction mixture was dark red again. After stirring at 50° C. for one hour, the mixture was cooled to room temperature and concentrated in vacuo. Purification by MPLC (ISCO, EtOAc/MeOH: 100/0 to 90/10) afforded the desired product. The material was taken forward without further purification. MS m/z=388.3 [M+1]+. Calc'd for C19H29NSO2Si: 387.2.

Source