Preparation of α-chitin-based nanocomposite as an effective biocatalyst for microwave aided domino reaction

Abstract

In this paper, chitin (Ch) was extracted by an optimized method from cuttlebone of the Persian Gulf cuttlefish (Sepiidae, Cephalopoda). The extracted chitin was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and thermal gravimetric analysis (TGA) which showed that the extracted chitin was in alpha form. The degree of N-acetylation (DA) and degree of substitution (DS) of α-chitin were calculated using titration method and FTIR spectroscopy and found to be 80–82% and 19.57 respectively. The α-Chitin was used as biomolecules for the preparation of nanostructured Ch/ZnO via a hydrothermal method. The obtained nanocomposite was characterized using FT-IR, XRD, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) analysis. The antimicrobial aspect of Ch/ZnO nanocomposite was previously proposed. In this paper, attempt was made to add the catalytic feature to these traits. For this purpose, the nanostructured Ch/ZnO was used as reusable nanocatalyst in the green and efficient synthesis of Benzo[a]pyrano(2,3-c)phenazine derivatives thru a four components microwave aided domino reaction. Eco-friendly, easy work up and separation of the nanostructured catalyst are some of the highlighted features this protocol.

The Use of Chitin from the Molts of Mealworm (Tenebrio molitor) for the Removal of Anionic and Cationic Dyes from Aqueous Solutions

“…Contrary to the crab chitin spectrum, the mealworm chitin spectrum in the 1700–1600 cm −1 range has only one distinct peak at 1626 cm −1 indicating a hydrogen bond between the carbonyl groups of amide I and amide II of the same chain [ 21 , 22 ]. This may suggest that a significant part of the chitin coming from the mealworms has the form of β-chitin [ 23 ], typical of the highly elastic structures.…”

Waste-to-wealth transition: application of natural waste materials as sustainable catalysts in multicomponent reactions

“…Its catalytic activity was examined in the synthesis of the benzo[ a ]pyrano[2,3- c ]phenazine derivatives 114 by the treatment of intermediate 113 , aldehyde derivatives 1 , and malononitrile 10 under MW irradiation; intermediate 113 was obtained by the reaction of 2-hydroxynaphthalene-1,4-dione 62 with O -phenylenediamine 29 (Scheme 73). 113…”

“…It was explored as a catalyst in the synthesis of spiro-oxindoles 112 using isatin 59, dimedones 6, and active methylenes 10 (Scheme 71), wherein easy workup procedure, ease of nanocatalyst separation, higher yields, and reusability of the catalyst were the highlights of this method; the catalyst could be used eight times without any noticeable inactivity. 111 Rezazadeh et al used dried powdered cuttlebone as a catalyst in the synthesis of 3,4-dihydropyrimidin-2(1H)-ones 43 by 113 Patil and co-workers used calcined mussel shells (CMS) as a catalyst to synthesize 4H-pyrans 15 or 20 via the reaction of aldehydes 1, malononitrile 15, and ethyl acetoacetate 13 or dimedone 6 in aqueous media (Scheme 74). The CMS catalyst was studied using FT-IR, XRD, XRF, EDS, and SEM, which revealed the presence of various elements Ca, O, and C according to EDS, and it could be reused five times without any noticeable reduction in the activity.…”

A review on lawsone-based benzo[a]phenazin-5-ol: synthetic approaches and reactions

“…Subsequent Michael addition of 4 to benzylidenemalononitrile, produced via Knoevenagel condensation of arylaldehydes with malononitrile catalyzed by Ch/ZnO, provided the desired product 27 after cyclization of intermediate 28. 42 …”

“…Subsequent Michael addition of 4 to benzylidenemalononitrile, produced via Knoevenagel condensation of arylaldehydes with malononitrile catalyzed by Ch/ZnO, provided the desired product 27 aer cyclization of intermediate 28. 42 In addition, hyperbranched polyglycerol functionalized graphene oxide (GO-HPG-SO 3 H) as an efficient reusable catalyst was employed in the synthesis of benzo In 2020, Nikoorazm et al synthesized benzo[a]pyrano [2,3-c] phenazine derivatives 36 in 87-99% yields by the reaction of 3, 2a, aromatic aldehydes/isatine and malononitrile in the presence of La@guanine@SBA-15 (0.5 mol%), in EtOH at reux conditions for 2-5.5 h. The suggested reaction mechanism has been depicted in Scheme 14. Initially, the intermediate 37 was formed from the Schiff-base condensation of 2a and 3 in the presence of the catalyst.…”