- Lewis-Acid-Catalysed Activation of Nitriles: A Microwave-Assisted Solvent-Free Synthesis of 2,4-Disubstituted Quinazolines and 1,3-Diazaspiro[5.5]undec-1-enes
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Two different modes of cyclization take place to synthesize quinazoline, quinazolinone, and 1,3-diazaspiro[5.5]undec-1-ene derivatives through the Lewis-acid-catalysed activation of both aliphatic and aromatic nitriles in a single-step, solvent-free, and transition-metal-free reaction. An amidine is expected to form as an intermediate; this then undergoes intramolecular cyclization in a one-pot reaction sequence. The reaction is carried out under microwave irradiation using trimethylsilyltrifluoromethane sulfonate (TMSOTf) as a catalyst and nitriles as a nitrogen source with the respective reaction partners.
- Saikia, Ujwal Pratim,Borah, Geetika,Pahari, Pallab
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- An Efficient Three-component, One-pot Synthesis of Quinazolines under Solvent-free and Catalyst-free Condition
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An efficient green protocol for the synthesis of quinazolines in the absence of solvent and catalyst has been developed. 2,4-Disubstituted quinazolines have been synthesized from three-component one-pot reactions of 2-aminoaryl ketones, orthoesters, and ammonium acetate. The present method has advantages of operational simplicity, substrate generality, clean reaction, high yields (76-94%), and moderate reaction time. The plausible mechanism of the reaction has been proposed based on the spectral characterization and single crystal X-ray analysis of isolated intermediate.
- Bhat, Subrahmanya Ishwar,Das,Trivedi, Darshak R.
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p. 1253 - 1259
(2015/08/06)
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