One-pot synthesis of tetrazolo[1,5-a]pyrimidines under solvent-free conditions

Abstract

A series of 5,7-diaryl-4,7-dihydrotetrazolo [1,5-a]pyrimidines and 5-methyl-7-aryl-4,7-dihydrotetrazolo [1,5-a]pyrimidine-6-carboxylates were obtained from aryl aldehydes, 2-aminotetrazole, substituted acetophenones, or ethyl acetoacetate in good to excellent yields by proceeding through a simple, mild, and efficient procedure utilizing N,N,N,N-tetrabromobenzene-1,3-disulfonamide as catalyst.

Fe3O4@SiO2@propyl‐ANDSA: A new catalyst for the synthesis of tetrazoloquinazolines

“…As a part of our continuing effort toward the synthesis of tetrazolopyrimidine derivatives and other organic compoundes, and in continuation of our interest in the application of nano catalysts in organic reactions, herein, we describe the synthesis of tetrahydrotetrazolo[1,5‐ a ]quinazolines and tetrahydrobenzo[ h ]tetrazolo[5,1‐ b ]quinazolines through the condensation reaction of substituted aldehydes, 5‐aminotetrazole, and dimedone or 6‐methoxy‐3,4‐dihyronaphtalen‐1(2 H )‐one in the presence of Fe 3 O 4 @SiO 2 @Propyl–ANDSA (Scheme ).…”

N‐Bromosulfonamides catalyzed synthesis of new spiro [indoline‐3,4'‐pyrano[2,3‐c]pyrazole] derivatives

“…Probable reaction mechanism in this way that initially these catalysts releases Br + in situ , which act as an electrophilic species and accelerated the formation of products. Therefore, the following mechanism can be suggested for the synthesis of spiro[indoline‐3,4 ' ‐pyrano[2,3‐ c ]pyrazole] derivatives (Scheme ) . Also, using a catalytic amount of aqueous 48% HBr instead of TBBDA to afford no desired product, this result indicates that the generation of the protic acid HBr may not be the only factor responsible for the catalytic activity of TBBDA.…”

Efficient One‐Pot Synthesis of Quinazoline and Benzopyrano[2,3‐d]pyrimidine Derivatives Catalyzed by N‐Bromosulfonamides

“…In the Scheme , we suggested a mechanism for the conversion of the o ‐aminoaryl ketones, various aldehydes, and ammonium acetate to quinazoline derivatives. According to this mechanism, TBBDA can be releases Br + as electrophilic species and the carbonyl groups activated by this catalyst and gave products .…”