One-Pot Green Synthesis of 2-Oxo-2H-chromene-3-carbonitriles Using Dual-Frequency Ultrasonication
Abstract: A green synthesis of 2-oxo-2H-chromene-3-carbonitriles has been carried out in one step by reacting 2-hydroxybenzaldehydes or 2-hydroxyacetophenones with ethyl cyanoacetate under dual-frequency ultrasonica-tion (ultrasonic bath of 40 KHz and probe of 20 KHz). The compounds were obtained in very high yield, and their structures were confirmed by IR and NMR data.
Aruna,Kumar, S.,Sharma, S. P.,Vashisht, N.
p. 1508 - 1512
(2021/10/26)
Organo Photoinduced Decarboxylative Alkylation of Coumarins with N-(Acyloxy)phthalimide
A metal-free and mild, photoinduced decarboxylative 4-position alkylation of coumarins has been reported. Photoinduced single electron transfer has been initiated by utilizing the visible-light absorptivity of Eosin Y for a reductive generation of alkyl r
Tripathi, Krishna N.,Belal, Md.,Singh, Ravi P.
p. 1193 - 1201
(2020/01/02)
Iodine-mediated one-pot synthesis of 3-cyanocoumarins and 3-cyano-4-methylcoumarins
2-Hydroxybenzaldehydes 1a-e on reaction with malononitrile (2) in the presence of iodine as catalyst give 3-cyanocoumarins 3a-e in one step under thermal heating as well as under microwave irradiation. The latter conditions are much more efficient in terms of time (2-5 min) and yield as compared to the thermal conditions (2-2.5 h). Following a similar procedure, 3-cyano-4-methylcoumarins 3f-i were also prepared by the reaction of 2-hydroxyacetophenones 1f-i with 2.
Sharma, Dinesh,Makrandi, Jagdish K.
p. 527 - 531
(2014/06/10)
Synthesis of 3-cyano and 3-cyano-4-methyl-coumarins using phase transfer catalysis
Synthesis of 3-cyano and 3-cyano-4-methylcoumarins have been achieved by the reaction of 2-hydroxybenzaldehydes/2-hydroxyacetophenones with malanonitrile in biphase medium using phase transfer catalysis.
Seema,Kumar, Surender,Makrandi
p. 1307 - 1308
(2007/10/03)
Conversion of coumarins accompanied by opening and recyclization of the lactone ring. 1. Study of the reaction of 3-ethoxycarbonyl(3-acyl)coumarins with cyanoacetylhydrazine and its derivatives
A stepwise sequence for the interaction of 3-ethoxycarbonyl(acyl)coumarins with cyanoacetylhydrazine, its N-acetyl and N-isopropylidene derivatives, leading to the formation of 3-cyanocoumarins, is proposed and demonstrated. It was established that the 3-cyanocoumarins formed are also able to participate in further conversions by a type of Michael reaction.