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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 49, Number 2
JKCSEZ 49(2)
April 20, 2005 

 
Title
Synthesis of Pyrazolo[3,4-b]quinoxaline Derivatives (Part I)

Pyrazolo[3,4-b]quinoxaline 유도체의 합성 (제1보)
Author
Ho Sik Kim*, Hyung Chul Lee

김호식*, 이형철
Keywords
분자내 고리화반응, 피라조로[3,4-b]퀴녹살린류 , Intramolecular Cyclization, Pyrazolo[3,4-b]quinoxalines
Abstract
3-Methoxycarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline (7)과 m-trifluoromethylbenzenediazonium chloride를 반응시켜 3-[a-(m-trifluoromethylphenylhydrazono)methoxycarbonylmethyl]-1,2-dihydro-2-oxoquinoxaline (8)을 합성하고, 이것을 phosphoryl chloride와 반응시켜 2-chloro-3-[a-(m-trifluoromethylphenylhydrazono)methoxycar- bonylmethyl]quinoxaline (9)을 합성하였다. 화합물 9를 hydrazine hydrate와 반응시켜 분자내 고리화반응으로 1-(m-trifluoromethylphenyl)-3-hydrazinocarbonyl-1H-pyrazolo[3,4-b]quinoxaline(10)을 합성한 다음, 이것을 alkanoyl chloride류, 벤즈알데히드류 또는 isothiocyanate류와 반응시켜 1H-pyrazolo[3,4-b]quinoxaline류(12-14)를 각각 합성하였다. 그리고 화합물 14를 2N NaOH 용액에서 환류시키니 1,2,4-triazolyl-1H-pyrazolo[3,4-b]quinoxaline류(15)가 합성되었고, 화합물 13을 아세트산 무수물과 반응시켰더니 1,3,4-oxadiazolyl-1H-pyrazolo[3,4-b]quinoxaline류(16)로 고리화가 일어났다.

The reaction of 3-methoxycarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline (7) with m-trifluoromethylbenzenediazonium chloride gave 3-[a-(m-trifluoromethylphenylhydrazono)methoxycarbonylmethyl]-1,2-dihydro-2-oxoquinoxaline (8), whose reaction with phosphoryl chloride provided 2-chloro-3-[a-(m-trifluoromethylphenylhydrazono)- methoxycarbonylmethylquinoxaline (9). The reaction of compound 9 with hydrazine hydrate resulted in the intramolecular cyclization to give 1-(m-trifluoromethylphenyl)-3-hydrazinocarbonyl-1H-pyrazolo[3,4-b]quinoxaline (10). The reaction of compound 10 with alkanoyl chlorides, benzaldehydes or isothiocyanates afforded 1H-pyrazolo[3,4-b]quinoxalines (12-14), respectively. Refluxing of compounds 14 in 2N NaOH solution gave the 1,2,4-triazolyl-1H-pyrazolo[3,4-b]quinoxalines (15). The reaction of compounds 13 with acetic anhydride were also cyclized to the 1,3,4-oxadiazolyl-1H-pyrazolo[3,4-b]quinoxalines (16).

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