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...

The mechanism of the N-heterocyclic carbene (NHC)-catalyzed intramolecular Stetter reaction of salicylaldehyde 1 to yield chromanone 3 has been theoretically studied at the B3LYP/6-31G** level. This NHC-catalyzed reaction takes place through six elementary steps, which involve: (i) formation of the Breslow intermediate IN2; (ii) an intramolecular Michael-Type addition in IN2 to form the new C-C...

The synthesis of silaheterocycles through the first examples of an intramolecular silene Diels-Alder reaction is described.

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...

ABSTRACT An enantioselective synthesis of (3S,3aS,7aR)-wine lactone, a major aroma component white wine and citrus juices, was achieved starting from (S)-2-methyl-3-butenoic acid. intramolecular Diels–Alder reaction employed as key step.

The active site cysteine of pig liver thioltransferase was identified as Cys22. The kinetics of the reaction between Cys22 of the reduced enzyme and iodoacetic acid as a function of pH revealed that the active site sulfhydryl group had a pKa of 2.5. Incubation of reduced enzyme with [1-14C]cysteine prevented the inactivation of the enzyme by iodoacetic acid at pH 6.5, and no stable protein-cyst...

A novel and metal-free I2-mediated intramolecular C2 amidation of indoles under mild reaction conditions is developed. This methodology affords various indole fused tetracyclic compounds, such as benzo[4,5]imidazo[1,2-a]indoles by intramolecular C2 amidation of N-aryl substituted indoles. This C2 sulfonamidative cyclization also offers convenient access to indolo[2,3-b]indoles and dihydroindolo...

2-Nitroaryldifurylmethanes 1a and 1b, readily available by condensation of 2-nitrobenzaldehyde and 6-nitroveratraldehyde with 2-methylfuran, were transformed into indole, cinnoline and benzothiazine-3,1 derivatives. The reduction of 2-nitroaryldifurylmethanes gave the corresponding anilines 2a,b or indole 3 depending on the reaction conditions. A plausible mechanism for the last reaction involv...

An efficient diastereoselective rhodium catalyzed synthesis of indolines possessing two contiguous tetrasubstituted carbon centers has been achieved with good to excellent yields using ortho-vinylanilines and iminocarbenes derived from N-sulfonyl-1,2,3-triazoles. The reaction affords excellent cisdiastereoselectivity through the initial formation of a N-ylide followed by intramolecular trapping...

An unexpected and interesting intramolecular side reaction occurred during the attempted synthesis of glycosyl cyanides upon treatment of 1-O-acetyl-3-azido-3-deoxyallose derivatives with TMSCN and different Lewis acids. Exo-1,2-O-cyanoalkylidene derivatives formed by neighboring group participation and attack of cyanide underwent, after Lewis-acid mediated isomerization to the endo-isomer, int...