An efficient synthesis of 1,8-dioxo-octahydro-xanthene derivatives promoted by a room temperature ionic liquid at ambient conditions under ultrasound irradiation.
The condensation reaction involving an aldehyde and diketone was efficiently promoted by the Ionic liquid, [Hbim]BF(4) (IL) as a reaction medium with methanol as co-solvent at ambient temperature under ultrasonic irradiation to afford the corresponding 1,8-dioxo-octahydro-xanthene (xanthene) derivatives in excellent yields. The advantages of this method include among others the use of a recyclable, non-volatile ionic liquid, which promotes this protocol under ambient temperature without the requirement of any added catalyst. The reaction times and yields are compared with p-TSA catalyzed synthesis of xanthenes under thermal conditions, which is also reported for the first time under our reaction conditions.
Venkatesan
K
K
Organic Chemistry, Technology Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
Pujari
Suresh S
SS
Organic Chemistry, Technology Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
Lahoti
R J
RJ
Organic Chemistry, Technology Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
Srinivasan
K V
KV
Organic Chemistry, Technology Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India. Electronic address: kv.srinivasan@ncl.res.in.
D001880:Boranes / Q000737:chemistry; D002384:Catalysis; D009682:Magnetic Resonance Spectroscopy; D013055:Spectrophotometry, Infrared; D013696:Temperature; D014465:Ultrasonics; D014966:Xanthenes / Q000737:chemistry; D044004:Xanthones / Q000737:chemistry*
D001880:Boranes; D014966:Xanthenes; D044004:Xanthones; C021274:boron trifluoride