Regioselective Syntheses of 3-Benzyl-Substituted 7H-Thiazolo[3,2-a]pyrimidine-7-ones through Palladium-Catalyzed Heteroannulation of Acetylenic Compounds

Table 1

Melting points and yields of 3-aryl-substituted 7H-thiazolo[3,2-a]pyrimidine-7-ones.

Entry	Ar	m.p. (°C)	Yield (%)
4a		253–255	85
4b		228–230	78
4c		250–252	86
4d		269–271	75
4e		277–279	88
4f		265–267	90

^aReaction reagents and conditions: 2 (1.3 mmol), 2a–f (1 mmol), Et₃N (2 mmol), Pd(PPh)₃Cl₂ (0.03 mmol), CuI (0.06 mmol), and CH₃CN (5 mL), room temperature, 24 h.