ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

N-propargylation reaction of substituted 4H-pyrano[2,3-d]pyrimidine derivatives under conventional, ultrasound- and microwave-assisted conditions

Do Son Hai, Nguyen Thi Thu Ha, Do Tien Tung, Cao Thi Le, Hoang Huu Anh, Vu Ngoc Toan, Hoang Thi Kim Van, Duong Ngoc Toan, Nguyen Thi Kim Giang, Nguyen Thi Thu Huong, and Nguyen Dinh Thanh

Institute of Science and Technology, Ministry of Public Security of Vietnam, Hanoi, Vietnam

E-mail: nguyendinhthanh@hus.edu.vn

Received: 2 October 2021  Accepted: 28 December 2021

Abstract:

A series of substituted 4H-pyrano[2,3-d]pyrimidines were synthesized from corresponding substituted 4H-pyrans by ring-closing reaction with acetic anhydride or acetic acid in the presence of trifluoroacetic acid as catalyst. The successive alkylation reaction of lactam N–H bond on pyrimidine-4-one ring was carried out using propargylic bromide in dry acetonitrile in the presence of anhydrous potassium carbonate. Three procedures applied for this purpose, including MW-assisted heating conditions at power of 100 W, under conventional heating conditions in water bath at 50 °C, and under ultrasound-assisted heating conditions at 50 °C. Dry acetonitrile was used as reaction solvent. Excellent yields of N-propargyl-4H-pyrano[2,3-d]pyrimidine derivatives were obtained. The single-crystal X-ray structure of compound 6a has been recorded, and the study helps to confirm the structure of synthesized N-propargyl derivative of 4H-pyrano[2,3-d]pyrimidines 6a–6p.

Keywords: 1-Alkyne; Propargyl bromide; N-propargylation; 4H-pyrano[2,3-d]pyrimidines; Microwave-assisted; Ultrasound-assisted

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02213-0

Chemical Papers 76 (8) 5281–5292 (2022)