Results 191 to 200 of about 8,569 (252)
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Reductone and the Synthesis of Pteridines
Nature, 1948As we have pointed out1 that the 3-carbon atom unit comprising the ring atoms 6 and 7 and the exocyclic carbon atom (indicated in heavy type) in pteroic acid (I) might be derived from a triose, 3-phosphoglyceraldehyde and phosphodihydroxyacetone being specifically mentioned, the suggestion by O‘Meara, McNally and Nelson2 that the strongly reducing non ...
H. S. Forrest, James Walker
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Helvetica Chimica Acta, 2003
AbstractThe low solubility of pterins can drastically be improved by N2‐acylation or formation of the N2‐[(dimethylamino)methylene] derivatives. Both types of compounds can be alkylated under Mitsunobu conditions to form from N2‐acylpterins (see 2 and 3) and their derivatives (see 5, 6, 8, 9, 11, 13, 15, and 17) selectively the O4‐alkyl derivatives 22 ...
Wolfgang Pfleiderer, Qizheng Yao
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AbstractThe low solubility of pterins can drastically be improved by N2‐acylation or formation of the N2‐[(dimethylamino)methylene] derivatives. Both types of compounds can be alkylated under Mitsunobu conditions to form from N2‐acylpterins (see 2 and 3) and their derivatives (see 5, 6, 8, 9, 11, 13, 15, and 17) selectively the O4‐alkyl derivatives 22 ...
Wolfgang Pfleiderer, Qizheng Yao
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Three New Pteridines from the Leech Whitmania pigra
, 2013Chemical investigation on the dried material of the leech Whitmania pigra has led to the isolation of three new pteridines, including two new lumazines bearing a thieno[3,2-g]lumazine skeleton, whi...
Tao Li +3 more
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Polarographic Study of Pteridines
Journal of Pharmaceutical Sciences, 1966The electronegativity of the half-wave potentials of a series of pteridine congeners was found to be related to the substituent groups. The 2,4,7-triaminopteridines, 7-substituted 4-amino-2-aryl-6-pteridinecarboxarnides, and 4,7-diamino-2-aryl-6-pteridinecarboxamides were characterized, in that order, by decreasingly lower electronegative half-wave ...
Marvin E Rosenthale, Milton Lapidus
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Nature, 1948
ALTHOUGH many derivatives of pteridine, both natural and synthetic, are known, the parent substance pteridine (I) does not appear to have been described. This substance has now been prepared by the condensation of 4 : 5-diaminopyrimidine with glyoxal bisulphite.
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ALTHOUGH many derivatives of pteridine, both natural and synthetic, are known, the parent substance pteridine (I) does not appear to have been described. This substance has now been prepared by the condensation of 4 : 5-diaminopyrimidine with glyoxal bisulphite.
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Pteridines as reflecting pigments and components of reflecting organelles in vertebrates.
Pigment Cell Research, 1993This paper reviews evidence for the presence of pteridines in iridophores, leucophores, and xanthophores in a wide variety of vertebrate chromatophores, and argues that the chemical and functional distinction between pterinosomes and reflecting platelets
Lynn W. Oliphant, Jocelyn Hudon
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, 2009
Accurate information on the age of wild-caught animals is valuable for a variety of areas, but can be particularly difficult to obtain for small holometabolous insects, whose body size is fixed at the time of pupal eclosion. A variety of chemical groups,
S. Robson, R. Crozier
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Accurate information on the age of wild-caught animals is valuable for a variety of areas, but can be particularly difficult to obtain for small holometabolous insects, whose body size is fixed at the time of pupal eclosion. A variety of chemical groups,
S. Robson, R. Crozier
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Pteridines and purines as major pigments of the avian iris.
Pigment Cell Research, 1987Stromal pigments from the irises of 28 species of birds having brightly colored eyes were extracted and analyzed. Carotenoids were present in six species and they were the sole bright pigment in only two of these. The iris pigments of the majority of the
L. Oliphant
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, 1993
The lithistid sponge Corallistes uizdulatus, which inhabits the base (- 5 10 m) of the New Caledonian coral reef, is shown here to contain the pteridines 1-methylpteridine-2,4- dione}, alreadyknownfromanotherCwalliJtB, and thenew(lrR,2'S)-6-(1',2 ...
A. Guerriero +4 more
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The lithistid sponge Corallistes uizdulatus, which inhabits the base (- 5 10 m) of the New Caledonian coral reef, is shown here to contain the pteridines 1-methylpteridine-2,4- dione}, alreadyknownfromanotherCwalliJtB, and thenew(lrR,2'S)-6-(1',2 ...
A. Guerriero +4 more
semanticscholar +1 more source