New microsphere cobalt complex: preparation and catalytic consideration for the synthesis of some heterocyclic compounds

Abstract

Herein a novel cobalt complex prepared by combination of Co(NO3)2.6H2O and thiosalycilic acid. Prepared microsphere cobalt complex was characterized by XRD, FTIR, TGA, BET, ICP and SEM techniques. Also, we report here an efficient method for the preparation of pyrroloacridine‐1(2H)‐one derivatives from a three‐component condensation reaction of amine, dimedone, and isatin and synthesis of chromeno [2, 3‐ d] pyrimidin‐8‐amines by reaction of benzaldehyde, α‐naphthol, malononitrile, and ammonium acetate in the presence of microsphere cobalt complex as the catalyst. The microsphere cobalt complex can be recovered without great loss of catalytic activity.

ZnFe2O4@SiO2‐ascorbic acid: Green, magnetic, and versatile catalyst for the synthesis of chromeno[2,3‐d] pyrimidine‐8‐amine and quinazoline derivatives

“…The mechanism provided for the preparation of chromeno from benzaldehyde, ammonium acetate, malononitrile, and α-naphthol using ZnFe 2 O 4 @SiO 2ascorbic acid as a catalyst is described in Scheme 4. [31,67] Firstly, the reaction was granted to start through the activation of the carbonyl group of the aldehyde via protonation by ZnFe 2 O 4 @SiO 2 -ascorbic acid as a Bronsted acid T A B L E 1 Optimization of the reaction conditions for the cyclocondensation of 4-chlorobenzaldehyde, ammonium acetate, and α-naphthol with malononitrile in the presence of ZnFe 2 O 4 @SiO 2 -ascorbic acid as the model reaction for the synthesis of 7,10-bis (4-chlorophenyl)-7H-benzo [7,8]chromeno [2,3-d] [66] 2 2 74 189-194 [66] 3 2 80 205-212 [66] 4 2 85 158-160 [66] T A B L E 2 (Continued)…”

“…268-273 [66] 6 2 95 252-258 [66] (Continues) S C H E M E 4 Suggested mechanism for the synthesis of 7,10-diphenyl-7Hbenzo [7,8]chromeno [2,3-d]pyrimidin-8-amine catalyzed of ZnFe 2 O 4 @SiO 2ascorbic acid catalyst. Then, 2-benzylidene malononitrile (3) was formed by Knoevenagel's addition of malononitrile to benzaldehyde catalyzed by ZnFe 2 O 4 @SiO 2 -ascorbic acid.…”