1.1
Reagents:
Pyridine
Solvents:
Dichloromethane
2.1
Reagents:
Hydrochloric acid
Solvents:
Methanol
,
Tetrahydrofuran
,
Water
;
3.5 h, rt
3.1
Reagents:
Pyridine
Catalysts:
4-(Dimethylamino)pyridine
Solvents:
Benzene
;
rt; 24 h, reflux; reflux → rt
3.2
Reagents:
Hydrochloric acid
Solvents:
Water
4.1
Reagents:
Hydrochloric acid
Solvents:
Tetrahydrofuran
,
Water
;
11 d, rt