+ Translate

Photochemistry of benzothiazole models of pheo melanin

, : Photochemistry of benzothiazole models of pheo melanin. Photochemistry & Photobiology 39(1): 5-10

The photochemistry of several 4-hydroxy- and 4-methoxybenzothiazoles was investigated by laser flash photolysis. In aqueous solutions of ph 3-12, the 4-hydroxybenzothiazole chromophore undergoes monophotonic photoionization to afford eaq- with quantum yields on the order of 0.06; no evidence for triplet species was obtained. The spectra and stability of the resultant free radicals were determined using pulse radiolysis. In contrast, triplet transients with life-times on the order of 8 .mu.s are readily observable upon irradiation of the 4-methoxybenzothiazole analog. Triplet sensitization experiments with the water-soluble carotenoid crocetin were employed to obtain the triplet extinction coefficients and subsequently the triplet quantum yields. The significance of these differences in photochemical behavior is discussed in relationship to the photochemistry and photobiology of the epidermal melanin pigment pheomelanin.

(PDF 0-2 workdays service)

Accession: 006110317

Submit PDF Full Text: Here

Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:

Related references

Patil D.G.; Chedekel M.R., 1984: Pheo melanin photochemistry. Photochemistry & Photobiology 39(SUPPL): 36S

Liu C T.; Chedekel M.R., 1982: Pheo melanin photochemistry photolysis of model compounds. Two pheomelanin model compounds were prepared and their photochemistries examined. Upon irradiation, an O2 mediated photopolymerization reaction was observed. The photopolymers obtained were characterized by their apparent MW, UV and fluorescence...

Rozanowska, M.; Sarna, T.; Land, E.J.; Truscott, T.G.orge, 1999: Free radical scavenging properties of melanin interaction of eu- and pheo-melanin models with reducing and oxidising radicals. The human skin and eye melanin is commonly viewed as an efficient photoprotective agent. To elucidate the molecular mechanism of the melanin-dependent photoprotection, we studied the interaction of two synthetic melanins, dopa-melanin and cysteiny...

Chedekel, M.R.; Post, P.W.; Deibel, R.M.; Kalus, M., 1977: Photo destruction of pheo melanin. Pheomelanin readily decomposes by the action of UV light and O2. This finding may explain many of the abnormal reactions of the skin of redheads and blondes to sunlight, including their high susceptibility to skin cancer. In aqueous solution, pheo...

Aquaron R.; Rouge F.; Aubert C., 1980: Pheo melanin in albino negroes. Yale Journal of Biology & Medicine 53(5): 396

Chedekel M.R.; Land E.J.; Sinclair R.S.; Tait D.; Truscott T.G., 1980: Photochemistry of 4 hydroxy benzothiazole a model for pheomelanin photo degradation. Journal of the American Chemical Society 102(21): 6587-6590

Patil D.G.; Chedekel M.R., 1984: Synthesis and analysis of pheo melanin degradation products 2. The syntheses of 2 of the HI degradation products, i.e., .alpha.-amino-.beta.-(4-hydroxy-7-benzothiazolyl)propionic acid and .alpha.-amino-.beta.-(3-hydroxy-4-aminophenyl)propionic acid, of the red-brown polymeric pheomelanin pigment in humans are...

Agin, P.P.; Sayre, R.M.; Chedekel, M.R., 1980: Photo degradation of pheo melanin an in vitro model. A new in vitro model system for studying the photochemistry and photobiology of melanins in [human] epidermal tissue was developed. The photochemistry of pheomelanin in this model system follows the same course as in pH 8.0 aqueous buffered soluti...

Matsueda S.; Nebuya C.; Takeuchi T., 1980: Structural analysis of pheo melanin from yellow mice. Yale Journal of Biology & Medicine 53(5): 396

Chedekel M.R.; Post P.W.; Vessell D.L., 1980: Effects of ph and wavelength upon the photo destruction of pheo melanin. Klaus, S N (Ed ) Pigment Cell, Vol 4 Biologic Basis Of Pigmentation; Proceedings Of The 10th International Conference, Cambridge, Mass , Usa, Oct 8-12, 1977 Xvi+358p S Karger: Basel, Switzerland; New York, N Y , Usa Illus P323-328, 1979