1.1
Reagents:
Potassium carbonate
Solvents:
Acetonitrile
;
2 h, reflux; reflux → rt
1.2
Reagents:
Trifluoroacetic acid
Solvents:
Dichloromethane
;
16 h, reflux; reflux → rt
1.3
Reagents:
Sodium hydroxide
Solvents:
Water
;
basified, rt
2.1
Reagents:
Diisopropylethylamine
,
O-(Benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoroborate
Solvents:
Dimethylformamide
;
overnight, rt