Efficient one-pot preparation of 5-substituted-2-amino-1,3,4-oxadiazoles using resin-bound reagents

The reaction of (N‐isocyanimino) triphenylphosphorane with an electron‐poor α‐haloketone in the presence of aromatic carboxylic acids: A novel three‐component reaction for the synthesis of disubstituted 1,3,4‐oxadiazole derivatives

“…The 1 H NMR spectrum of 4a consisted of a singlet for the CH 3 (δ = 1.93), a hydroxy hydrogen atom (δ = 4.51), exchangeable by D 2 O and two doublet for the aromatic protons (δ = 7.50 and 7.99, 3 J HH = 8.5 Hz). The 1 H decoupled 13 C NMR spectrum of 4a showed nine distinct resonances, partial assignment of these resonances is given in the Experimental section. The 1 H and 13 C NMR spectra of compounds 4b-k were similar to those of 4a, except for the aromatic and aliphatic moieties, which exhibited characteristic signals with appropriate chemical shifts.…”

Preparation of Fully Substituted 1,3,4-Oxadiazole Derivatives from N-Isocyaniminotriphenylphosphorane, (E)-Cinnamic Acids, Chloroacetone and Primary Amines

“…synthesis of 1,3,4-oxadiazoles, especially from available carboxylic acids and acid hydrazides. [14][15][16] As part of our ongoing program to develop efficient and robust methods for the synthesis of heterocyclic compounds, 17-20 we wish to report the preparation of a new class of 1,3,4-oxadiazole derivatives 5a-o by a novel Four-component condensation reaction of chloroacetone 1, primary amine 2, (N-isocyanimino)triphenylphosphorane 4 and (E)-cinnamic acids 3 in excellent yields under neutral conditions (Scheme 1).…”

Polymer‐Supported Organosuperbases

“…In this sequence, PS-BEMP was successfully used for both the deprotonation of acyl hydrazides and N-alkylation of weakly acidic triazoles. Using the conceptually analogous cyclodehydration strategy, a variety of 2-amino-1,3,4-oxadiazole derivatives, an important class of heterocycles in medicinal chemistry, were also prepared by the PS-BEMP promoted cyclization of diacyl hydrazides and related compounds [66][67][68]. In some cases, the use of microwave irradiation was extremely useful for facilitating rapid access to the desired products [68].…”