Synthesis 2025; 57(01): 154-166
DOI: 10.1055/a-2348-5564
paper
Special Topic Dedicated to Prof. H. Ila

Dehydration in Water: A Reagentless and Straightforward Synthesis of Tetrahydroquinazolines under Microwave Irradiation or by Stirring at Room Temperature, and Their Subsequent Conversion into Quinazolines in a Micellar Medium

Padmini. C. Panjikar
a   Department of Chemistry, Birla Institute of Technology and Sciences, KK Birla Goa Campus, NH 17B Bypass Road, Zuarinagar, Goa 403726, India
b   Department of Chemistry, Parvatibai Chowgule College of Arts & Science (Autonomous), Margao, Goa 403602, India
,
Abigail. B. Pinheiro
a   Department of Chemistry, Birla Institute of Technology and Sciences, KK Birla Goa Campus, NH 17B Bypass Road, Zuarinagar, Goa 403726, India
,
Soumik Saha
a   Department of Chemistry, Birla Institute of Technology and Sciences, KK Birla Goa Campus, NH 17B Bypass Road, Zuarinagar, Goa 403726, India
,
Amrita Chatterjee
a   Department of Chemistry, Birla Institute of Technology and Sciences, KK Birla Goa Campus, NH 17B Bypass Road, Zuarinagar, Goa 403726, India
,
Mainak Banerjee
a   Department of Chemistry, Birla Institute of Technology and Sciences, KK Birla Goa Campus, NH 17B Bypass Road, Zuarinagar, Goa 403726, India
› Institutsangaben
M.B. is grateful to the Department of Biotechnology, Ministry of Sci ence and Technology, India (DBT-BUILDER) (Project no. BT/INF/22/SP42543/2021) for financial support.


This article is dedicated to Prof. H. Ila, JNCASR, Bangalore on the occasion of her 80th birthday

Abstract

Using a reagent- and catalyst-free approach, a series of 2-substituted 1,2,3,4-tetrahydroquinazolines is synthesized by cyclocondensation between aldehydes and 2-aminobenzylamines via dehydration in water. The reactions are complete in 2 minutes under microwave irradiation and proceed well under stirring at room temperature, affording tetrahydroquinazolines in high to excellent yields. The products are water-insoluble and are isolated by simple filtration, avoiding a conventional work-up step and offering an organic-solvent-free process. Furthermore, the tetrahydroquinazolines are efficiently oxidized in a micellar medium derived from cetyltrimethylammonium bromide (CTAB) using a cheap commercial bleaching solution (4% NaOCl in water) to give quinazolines in high yields. This sustainable protocol has a near zero E-factor.

Supporting Information



Publikationsverlauf

Eingereicht: 13. Mai 2024

Angenommen nach Revision: 19. Juni 2024

Accepted Manuscript online:
19. Juni 2024

Artikel online veröffentlicht:
15. Juli 2024

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