Halogenation Reaction of Purpurin-18 and Synthesis of Chlorin Derivatives

Ranran Liu, Jungang Yin, Jiazhu Li, Jin Wu, Guanlong Chen, Yingxue Jin, Jinjun Wang
2012 Youji huaxue  
From purpurin-18 methyl ester the electrophilic addition of C(3)-vinyl group and electrophilic substitution at 20-meso-position produced regioselectively corresponding chloro-substituted or bromo-substituted products. The 3-pyrazolinylpurpurin-18 ester, obtained by 1,3-dipolar cycloaddition of purpurin-18 with diazomethane, reacted with N-bromosuccinimide (NCS) or N-chlorosuccinimide (NBS) to generate halogenated pyrazolinyl-substituted chlorins. After pyrolysis the halogenations of
more » ... ions of 3-pyrazolinylpurpurin-18 ester gave 20-halogenated 3-cyclopropylchlorins. Methyl pheophorbide-a was used another starting material and converted into 20-bromopurpurin-18 derivatives by a series of chemical conversion for C(3)vinyl group and bromination at 20-position. The structures of newly-reported title compounds were characterized by elemental analysis, UV, IR and 1 H NMR spectra.
doi:10.6023/cjoc1105231 fatcat:q46siaqcqngd5iing7tvkzhj5m