Điều chế benzofuran-2-carbohydrazide để tổng hợp benzofuran mang 1,2,4-triazole và 1,3,4-oxadiazole

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Tác giả: Thị Châu Ngô

Ngôn ngữ: vie

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Thông tin xuất bản: Tạp chí Khoa học và Công nghệ - Đại học Nguyễn Tất Thành, 2023

Mô tả vật lý: tr.81

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ID: 341563

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Benzofuran, triazole and oxadiazole spontaneously occur in natural compounds with highly desired bioactivities, such as antibacterial, antifungal, antiviral and anticancer. These cyclic scaffolds happen in a variety of commercial medicines as well as developed drugs in late-stage clinical trials (eg. amiodarone, ramelteon, zibotentan, and ataluren). Benzofuran-bearing triazole and oxadiazole can be synthesized by click reaction, requiring an alkynyl group. The formation of the alkynyl group can be achieved by treating the precursor with sodium azide, a poisonous chemical that needs safe conditions for manipulation. In this study, a simple and convenient reflux-based method for the synthesis of benzofuran-involved triazole and oxadiazole was developed. Firstly, benzofuran-2-carbohydrazide (3) was prepared by the reaction of salicylaldehyde and ethyl chloroacetate, followed by the treatment with hydrazine hydrate. Subsequently, compound (3) reacted with KOH, CS2 and hydrazine hydrate to afford 4-amino-1,2,4-triazole-3-thiol derivative (4), existing in a tautomeric form with its thione isomer (4b) in 1:3 of molar ratio. Intriguingly, the reaction of (3) and 4-fluorobenzaldehyde afforded N'-(4-fluorobenzoyl)-1-benzofuran-2-carbohydrazide (6) instead of 1,3,4-oxadiazole derivatives. Their structures were confirmed by NMR and MS. Altogether, this study implies the potential of using the simple and cost-effective reflux-based method for benzofuran-bearing triazole and oxadiazole synthesis.Các dị vòng benzofuran, triazole and oxadiazole thường được tìm thấy trong các hợp chất tự nhiên với những hoạt tính sinh học quý báu như kháng khuẩn, kháng nấm, kháng vi rut và kháng ung thư. Những dị vòng này cũng thường xuất hiện rộng rãi trong các loại thuốc đang được sử dụng hằng ngày hoặc những loại thuốc quý đang được thử nghiệm lâm sàng giai đoạn cuối (thí dụ như amiodarone, ramelton, zibotentan, và ataluren). Các dẫn xuất triazole và oxadiazole chứa dị vòng benzofuran thường được tổng hợp thông qua phản ứng “Click” dựa trên nền chất có nhóm chức alkynyl. Tuy nhiên, tổng hợp chất nền với nhóm chức alkynyl thường dựa trên tác chất sodium azide, một hợp chất khá độc với con người và vì vậy đòi hỏi độ an toàn và điều kiện thí nghiệm khắc khe. Để giải quyết vấn đề này, phương pháp tổng hợp dẫn xuất triazole và oxadiazole chứa dị vòng benzofuran sử dụng dụng cụ đơn giản, tiết kiệm và hiệu quả được nghiên cứu và đánh giá. Hợp chất benzofuran-2-carbohydrazide (3) được tổng hợp bằng phản ứng của salicylaldehyde, ethyl chloroacetate và hydrazine. Sau đó, hợp chất (3) phản ứng với KOH, CS2 và hydrazine tạo thành dẫn xuất 4-amino-1,2,4-triazole-3-thiol (4), tồn tại trong hợp hai isomers (thiol và thione) với tỉ lệ mole là 1:3. Phản ứng giữa hợp chất (3) và 4-fluorobenzaldehyde tạo thành dẫn xuất N'-(4-fluorobenzoyl)-1-benzofuran-2-carbohydrazide (6), thay vì 1,3,4-oxadiazole như mong đợi. Cấu trúc hoá học của các dẫn xuất tổng hợp trong bài được xác định bằng các phương pháp phổ hiện đại như NMR và MS. Công trình nghiên cứu này phát triển phương pháp tổng hợp dẫn xuất triazole and oxadiazole chứa dị vòng benzofuran một cách hiểu quả và tiết kiệm.

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