Kang J, Yeong Kim S, Hee Jo H, Zong K. Triflic Acid-Assisted Regioselective Bromination of Quinoxaline Derivatives Enables a Facile Synthesis of Polymer PTQ10.
CHEMSUSCHEM 2024:e202400216. [PMID:
38627218 DOI:
10.1002/cssc.202400216]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/16/2024] [Indexed: 05/16/2024]
Abstract
Poly[(thiophene)-alt-(6,7-difluoro-2(2-hexyldecyloxy)quinoxaline)] (PTQ10) emerges as a promising candidate for donor materials in organic solar cells (OSCs) due to its high efficiency, simplified synthesis, and cost-effectiveness. The acceptor unit of PTQ10 is derived from the alkylation of 5,8-dibromo-6,7-difluoroquinoxaline-2-ol, emphasizing the importance of its economical synthesis for commercial viability. This study investigates triflic acid-assisted regioselective bromination of quinoxaline derivatives and proposes an alternative synthetic pathway for PTQ10. The developed route benefits from concise synthetic steps, a dependable procedure, and high overall yield. Starting with the condensation of 4,5-difluorobenzene-1,2-diamine with ethyl oxoacetate to yield 6,7-difluoroquinoxaline-2-ol, subsequent triflic acid-assisted regioselective bromination produces 5,8-dibromo-6,7-difluoroquinoxaline-2-ol in high yield. Alkylation under Mitsunobu reaction conditions yields 5,8-dibromo-6,7-difluoro-2-(2-hexyldecyloxy)quinoxaline, followed by polymerization with 2,5-distannylated thiophene under Stille reaction conditions to afford PTQ10. This research provides insights into efficient synthetic strategies for PTQ10, advancing its potential for commercial application in OSCs.
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