Introduction of a third meso substituent into 5,10-diaryl chlorins and oxochlorins.
Chlorins/oxochlorins bearing distinct patterns of substituents are valuable compounds in bioorganic and materials chemistry. Treatment of a 5,10-diaryl-substituted chlorin or oxochlorin with TFA-d(1) resulted in selective deuteriation of the remaining meso positions (15, 20) rather than any of the beta-pyrrolic positions. Electrophilic iodination or bromination of a 5,10-diaryl-substituted chlorin proceeded with high regioselectivity, affording the 5,10-diaryl-15-halo-substituted chlorin. Iodination or bromination of a free base 5,10-diaryloxochlorin gave a mixture of products arising through halogenation at the 15-, 20-, and beta-pyrrolic positions, while bromination of a zinc 5,10-diaryloxochlorin selectively gave the 5,10-diaryl-20-bromo-substituted oxochlorin. The Suzuki coupling reaction of a phenyl boronic acid derivative and a 5,10-diaryl-15-iodooxochlorin or 5,10-diaryl-20-bromooxochlorin gave the corresponding 5,10,15- or 5,10,20-triaryloxochlorin. The introduction of a third aryl substituent into the chlorin or oxochlorin causes an approximately 5-nm red shift of the long wavelength Q(y) absorption band. Two phenylethyne-linked oxochlorin-oxochlorin dyads in distinct metalation states (zinc/free base, free base/zinc) were prepared by Sonogashira coupling reactions of a 5,10-diaryl-20-bromooxochlorin and a 10-substituted ethynylphenyl oxochlorin. This study provides access to new chlorins/oxochlorins that can be utilized in diverse applications.
Taniguchi
Masahiko
M
Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA.
Kim
Man Nyoung
MN
Ra
Doyoung
D
Lindsey
Jonathan S
JS
D002384:Catalysis; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008665:Metalloporphyrins / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry; D015032:Zinc / Q000737:chemistry*
D006846:Hydrocarbons, Halogenated; D008665:Metalloporphyrins; D011166:Porphyrins; C006969:chlorin; D010165:Palladium; D015032:Zinc