Highly efficient and facile synthesis of densely functionalized thiazolo[3,2-a]chromeno[4,3-d]pyrimidin-6(7H)-ones using [Bmim] BF4 as a reusable catalyst under solvent-free conditions

作者：Reddy Avuthu Vidya Sagar; Jeong Yeon Tae

来源：Tetrahedron, 2016, 72(1): 116-122.

DOI：10.1016/j.tet.2015.11.010

• Chromenopyrimidines
• 1-Butyl-3-methylimidazolium tetrafluoroborate
• Multicomponent reaction
• Solvent-free condition

An efficient and concise synthesis of structurally diverse thiazolo[3,2-a]chromeno[4,3-d]pyrimidin-6(7H)-one derivatives (4a-4ab) with good to excellent yields has been developed. This reaction is a versatile one-pot multicomponent condensation of 4-hydroxycoumarins, 2-aminobenzothiazoles, and various aldehydes catalyzed by eco-friendly and reusable 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid under solvent-free conditions. Several advantages of this protocol include its operational simplicity, short reaction time, efficient utilization of all the reactants, non-chromatographic purification procedure, wide functional group tolerance, and ease of recovery and reuse of the catalyst for at least five consecutive cycles without loss of activity.

• 出版日期2016-1-7