The depolymerization of N- substituted oligourethanes via an intramolecular cyclization event was studied in-depth, while the applicability these macromolecules as anti-counterfeiting tags demonstrated by labeling a polyurethane material.

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 reaction of 1-alkenoylcyclopropane carboxylic acids with NBS or NIS was investigated, which provides an efficient route to biologically important 7-halogenated furo[3,2-c]pyran-4-ones in a one-pot transformation. The major pathway for the formation of the O-O heterocycles was proposed as a halo-oxa-cyclization, HBr elimination, cyclopropane ring-opening and recyclization (intramolecular oxa...

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 intramolecular C-H insertion of the Mes*-substituted phosphanylidenecarbene [Mes*P=C:] (Mes* = 2,4,6-t-Bu3C6H2) and physicochemical properties of the cyclized product, 6,8-di-tert-butyl-3,4-dihydro-4,4-dimethyl-1-phosphanaphthalene were studied based on ab initio calculations. Whereas the alternative Fritsch-Buttenberg-Wiechell-type rearrangement requires almost no activation energy, the in...

Polyfunctionalized carbazole derivatives have been synthesized by a one-pot reaction between indoles and keto-functionalized nitroolefins. The first step is based on Friedel-Crafts followed acid-promoted microwave-assisted intramolecular cyclization.

A facile synthesis of highly functionalized 2H-iminopyran derivatives by the multi-component reaction of cyclohexyl isocyanide, dialkyl acetylenedicarboxylates, arylglyoxals and arylamines is described. The zwitterionic intermediate produced by addition of cyclohexyl isocyanide to electron-deficient acetylene diesters was trapped by the electrophilic imine moiety of α-iminoketones, derived from...

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...

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...

A novel Cu(II)-catalyzed cyclization of α-diazo-β-oxoamides with amines has been developed, constituting a straightforward method to construct pyrrol-3(2H)-one rings. The intramolecular hydrogen bonding effect in α-diazo-β-oxoamides plays an essential role in this reaction. A plausible reaction mechanism involving divergent generation and subsequent [2 + 3] cyclization of ketene and α-diazoimin...