Ultrasound-promoted synthesis of novel dihydropyrido[2,3-d:5,6- d`]dipyrimidine derivatives

An efficient synthesis of dihydropyrido[2,3-d:5,6-d`]pyrimidine derivatives was developed via one-pot three-component reaction of 6-amino-2-(alkylthio)-pyrimidine-4(3H)one and aryl aldehydes in the mixed solvent of glacial acetic acid and DMF (1:1, v:v) under ultrasonic irradiation. In this protocol novel fused dihydropyrido[2,3-d]pyrimidines were synthesized in high yields (80-97%) and lower reaction times (5-25 min)

Ultrasonic-assisted ruthenium-catalyzed one-pot synthesis of biscoumarins

The Ru-grafted zeolite beta was found to be an excellent heterogeneous catalyst for one-pot synthesis of biscoumarins. This reaction was carried out under reflux condition and ultrasonic irradiation. On the other hand, the catalyst could be recovered for the subsequent reactions and reused without appreciable loss of activity

Synthesis of biscoumarin derivatives by the reaction of aldehydes and 4-hydroxycoumarin using ruthenium (III) chloride hydrate as a versatile homogeneous catalyst

The one-pot domino Knoevenagel-type condensation/Michael reaction of aromatic, heteroaromatic and aliphatic aldehydes with 4-hydroxycoumarin in aqueous media in the presence of ruthenium salt as homogeneous catalyst was investigated. It was found that 5 mol% of RuCl3.nH2O catalyzes biscoumarin synthesis in high yields (70-95%) under optimised, mild, green and environmentally benign reaction conditions in short times (25-35min)

An easy conversion of carbamates of β-amino esters into the β-lactams

724-731A facile and direct conversion of carbamates of unsaturated β-amino esters derived from Baylis–Hillman adducts into their corresponding α-methylene β-lactams and α-arylidene β-lactams by potassium tert-butoxide (KOtBu) at room temperature and in excellent yields is described. This system is efficient, cheap, and easily available and reacts under mild reaction conditions for the selective preparation of β-lactam derivatives from their carbamates

Convergent and efficient synthesis of 1,2,4-triazolo[5,1-b]quinazolin-8-ones using copper incorporated hydroxyapatite encapsulated Kit-6 as a recoverable nanocatalyst

856-865Copper incorporated hydroxyapatite encapsulated Kit-6 (Cu@HAp@KIT-6) has been used as an effective nanocatalyst in the synthesis of 1,2,4-triazolo[5,1-b]quinazolin-8-one derivatives by a one-pot reaction of 3-amino-1,2,4-triazole, dimedone and aromatic aldehydes in ethanol. This novel protocol affords the products under optimized reaction conditions with high to excellent yields (88-97%) and lower reaction times (40-50 min). Wide substrate scope, facile work-up procedure, reduced reaction time, the use of green solvent and recyclability of the catalyst are some prominent advantages of this protocol. The catalytic activity of the catalyst after six consecutive runs has been preserved without an appreciable decrease in its activity

One-pot conversion of carbamates of unsaturated β-aminoesters into unsaturated β-lactams by use of trimethylsilyl iodide

<p>Trimethylsilyl iodide (TMSI) is introduced as an efficient reagent for the one-pot and direct transformation of carbamates of unsaturated β-aminoesters into the corresponding α-methylene-β-lactams and α-arylidene-β-lactams. The mild reaction conditions, excellent yields and easy work-up procedures make it a useful alternative to previously applied procedures for the rapid synthesis of β-lactams from easily available Baylis-Hillman adducts.</p