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Eleven new tetrahydrobenzo[b]pyran derivatives were synthesized via a three component reaction of different aromatic aldehydes, methyl cyanoacetate and 1,3-cyclohexadione, with water as solvent under catalyst-free microwave irradiation. The structures of all the new molecules were well analysed and their structures established by using various spectral techniques (1H NMR, 13C NMR, 15N NMR and HRMS). Various advantages of reported protocol are the ease of preparation, short reaction times (10 min), aqueous solvent and excellent yields (89–98%). Additionally, this method provides a clean access to the desired products by simple workup.

A facile, swift and ecofriendly microwave-assisted multi-component/one-pot protocol is designed for the synthesis of novel pyrazolo-[3,4-b]-quinolines at ambient temperature in aqueous ethanol as a reaction medium.

A green approach is designed for the synthesis of 1,4‐dihydropyrine derivatives catalyzed by triethylamine with water as solvent and under microwave irradiation conditions. The title reaction involved the one‐pot condensation of four components, namely aryl aldehyde, benzyl acetoacetate, 5‐methyl‐1,3‐cyclohexanedione and ammonium acetate. Good to excellent yields (88‐98%), short reaction times (10 min), green solvent and simple workup are attractive features for the approach. The method requires no further chromatographic separation. The structures of all the ten new derivatives were fully characterized by spectroscopic analysis with 1H NMR, 13C NMR, 15N NMR and HRMS.

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