Cellulose sulfonic acid as a green, efficient, and reusable catalyst for Nazarov cyclization of unactivated dienones and pyrazoline synthesis. Issue 127 (11th December 2015)

• Record Type: Journal Article
• Authors: Daneshfar, Zahra; Rostami, Ali
• Is Part Of: RSC advances. Volume 5:Issue 127(2015)
• Page Start: 104695
• Page End: 104707
• Publication Date: 2015-12-11
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c5ra19773b
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A high yielding and eco-friendly procedure for the preparation of cyclopentenoid and pyrazoline derivatives via cellulose sulfonic acid-mediated electrocyclization processes. Abstract : A high yielding, eco-friendly and simple procedure for the synthesis of five membered carbo- and heterocycles through cellulose sulfonic acid (CSA) mediated electrocyclization processes has been developed. Cellulose sulfonic acid (CSA) not only was able to induce the cyclization of "unactivated" dienones generating cyclopentenoids; it was also able to trigger the cyclization of α, β-unsaturated hydrazones giving rise to pyrazolines in excellent yields under green reaction conditions. The ease of catalyst recovery and reusability, short reaction time, simple experimental and work-up procedure; compared to the conventional methods, makes this protocol practical, environmentally friendly and economically desirable. The cellulose-SO3 H (CSA) was characterized by FT-IR spectroscopy, powder X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) analyses, and catalyst stability was judged by thermogravimetry/differential thermal analysis (TG/DTA). The catalyst can be recycled several times without significant loss of catalytic activity.