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.
Organic Chemistry, Technology Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
K
K
Venkatesan
Organic Chemistry, Technology Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
Suresh S
SS
Pujari
Organic Chemistry, Technology Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India.
R J
RJ
Lahoti
Organic Chemistry, Technology Division, National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India. Electronic address: kv.srinivasan@ncl.res.in.
K V
KV
Srinivasan
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