Silica ferric hydrogensulfate is an efficient heterogeneous catalyst for the cyclization of 2- aminochalcones to the corresponding 2,3-dihydroquinolin- 4(1H)-ones. This intramolecular aza Michael reaction was carried out in high yields using chalcones bearing of electron donating and electron withdrawing groups. The catalyst is reusable without significant decreases in its activity after four t...

results of the bromination and dehydrobromination of several angular methylated decalindiones are described. the key reaction, base-induced cyclization of the monobromo keto ester (3), and the dibromo ketone (4), leads to the formation of tricyclic systems (6) and (9) respectively.

A general, simple, practical and convenient method has been described for the synthesis of anesthetic drug thiopental using thiourea in the presence of sodium ethoxide. Anesthetic drug of thiopental was prepared in two stages; during the first stage, the alkylation of mthyl cyanoacetate was performed which was then to be followed by cyclization. Alkylation of methyl cyanoacetate which was perfo...

A straightforward stereoselective and enantiodivergent cyclization strategy for the construction of γ-lactams is described. The cyclization strategy makes use of chiral malonic esters prepared from enantiomerically enriched monoesters of disubstituted malonic acid. The cyclization occurs with the selective displacement of a substituted benzyl alcohol as the leaving group. A Hammett study illust...

The lantibiotic synthetases LctM and HalM2 are bifunctional enzymes that catalyze both the dehydration of serine and threonine residues and the Michael-type additions of cysteine residues to the resulting dehydroamino acids in their substrate peptides. Using Fourier transform mass spectrometry to analyze these activities in vitro, the dehydration is shown to take place by a distributive mechani...

Backbone cyclization has a profound impact on the biological activity and thermal and proteolytic stability of proteins and peptides. Chemical methods for cyclization are not always feasible, especially for large peptides or proteins. Recombinant Staphylococcus aureus sortase A shows potential as a new tool for the cyclization of both proteins and peptides. In this review, the scope and backgro...

Results of the bromination and dehydrobromination of several angular methylated decalindiones are described. The key reaction, base-induced cyclization of the monobromo keto ester (3), and the dibromo ketone (4), leads to the formation of tricyclic systems (6) and (9) respectively.

An efficient cyclization of 2’-hydroxychalcone to flavanone using calcium chloride as a catalyst was developed. The scope of the reaction was studied with substituted 2’-hydroxychalcone and these chalcones was converted into corresponding flavanone in good yield. The merits of this method are inexpensive and easily available catalyst, easy workup procedure, avoid use of toxic solvent.