Boric acid in aqueous micellar medium: an effective and recyclable catalytic system for the synthesis of aryl-7,8-dihydro[1,2,4]triazolo[4,3-a]pyrimidine-6-carbonitriles

A one-pot three-component reaction involving 2-aminochromone in aqueous micellar medium: a green synthesis of hexahydrochromeno[2,3- $$b$$ b ]quinolinedione

“…Use of a 0.6 M aqueous CTAB solution gave 70 % of 7a. No improvement in yield was noticed on increasing the molar concentration of CTAB (entries [12][13][14], whereas anionic surfactant SDS was found to be more efficient (entries [15][16][17]. Heating an equimolar mixture of 1a, 2a and 3a in 0.5 M aqueous SDS at 80-90 • C for 4 h becomes the optimized reaction condition (entry 16).…”

“…Factors responsible for organic reactions in aqueous medium include the Breslow hydrophobic effect [13], H-bonding, polarity effect and the Marcus transphase H-bonding phenomena [14]. Another approach to carry out organic reactions in aqueous medium is by using micelles [15][16][17].…”

Synthesis of pyrimidine-6-carbonitriles, pyrimidin-5-ones, and tetrahydroquinoline-3-carbonitriles by new superb oxovanadium(V)-[5,10,15,20-tetrakis(pyridinium)-porphyrinato]-tetra(tricyanomethanide) catalyst via anomeric based oxidation

“…Triazolopyrimidines and tetrahydroquinolines were synthesized by using numerous approaches and catalysts such as thiamine hydrochloride (VB 1 ) 23 , Nafion-H 24 , phthalhydrazide-MCM-41 (P-MCM-41) 25 , boric acid under aqueous micellar medium 26 , [DABCO](SO 3 H) 2 Cl 2 and [DABCO](HSO 3 ) 2 (HSO 4 ) 2 27 , DBU 28 , microwave irradiation 29 , etc. [30][31][32][33][34][35][36][37][38][39] .…”

α-Aminoazoles/azines: key reaction partners for multicomponent reactions

“… 138 It was observed that the replacement of NaOH by triethyl amine, l -proline or acetic acid did not yield the product under both heating conditions. This purine analogue containing triazolopyrimidines with a bridgehead nitrogen was also achieved with same combination of reacting components using catalysts such as boric acid (H 3 BO 3 ) in aqueous micellar, 139 DBU, 140 [H 2 -DABCO][H 2 PO 4 ] 2 or DABCO][ClO 4 ] 2 , 141 γ-Fe 2 O 3 @SiO 2 @[Bis-APTES]Cl 2 nanoparticles, 89 Brönsted acidic ionic liquid supported on rice husk ash (RHA-[pmim]HSO 4 ), 80 polyethylene glycol (PEG-400) in water, 142 nanoporous sodium montmorillonite clay (Na + -MMT)-modified 1-methyl-3-(trimethoxysilylpropyl)-imidazolium hydrogen sulfate (Na + -MMT-[pmim]HSO 4 ), 31 and 1,4-piperazinium hydrogen sulfate ([H-pi]HSO 4 ). 143 A brief summary of the information regarding the reaction conditions, reaction time, yield of product, etc.…”