- Synthetic method for preparing marine alkaloid Bacuacuacuanin-L intermediate
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The invention discloses a synthesis method for preparing a marine alkaloid Baculiferin-L intermediate. According to the method, a novel synthesis route suitable for the Baculiferin-L intermediate is designed, which is started from a raw material, substitu
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Paragraph 0078; 0081
(2020/07/13)
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- A general method for the synthesis of N-unsubstituted 3,4-diarylpyrrole-2, 5-dicarboxylates
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A general method for the synthesis of N-unsubstituted 3,4-diarylpyrrole-2, 5-dicarboxylates (3) has been developed. The key reactions involved are the Hinsberg-type synthesis of dimethyl N-benzyl-3,4-dihydroxypyrrole-2,5- dicarboxylate (6) followed by palladium-catalyzed Suzuki-Miyaura coupling of its bis-triflate derivative (7). The N-benzyl protecting group of the resulting 3,4-diaryl pyrrole-2,5-dicarboxyl ates (8) is cleanly removed under hydrogenolytic or solvolytic conditions.
- Fukuda, Tsutomu,Hayashida, Yukie,Iwao, Masatomo
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experimental part
p. 1105 - 1122
(2010/09/16)
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- Water-soluble xanthobilirubinic acids?
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Xanthobilirubinic acid, a model dipyrrinone for one-half of the bilirubin molecule in photochemical and metabolism studies, is more polar than bilirubin and insoluble in water and in chloroform. Replacing the β-alkyl substituents on the lactam ring of xanthobilirubinic acid with methyl-capped ethylene glycol, diethylene glycol, and triethylene glycol (PEG) groups steadily increased the water solubility of the pigment so that the last is completely soluble in both water and chloroform. Synthesized by base-catalyzed condensation of the corresponding methyl-capped 3,4-diPEG-pyrrolin-2-one with 3,5-dimethyl-4(2-ethoxycarbonylethyl)-2-formyl-1H-pyrrole, these new PEGylated analogs of xanthobilirubinic acid are yellow-colored dipyrrinones that form intermolecular hydrogen-bonded dimers in chloroform solution but are monomeric in methanol and water, as revealed by 1H NMR spectroscopy and vapor pressure osmometry. Methyl xanthobilirubinate has served as a synthetic precursor to bilirubinoids; its amphiphilic PEGylated analogs suggest a route to water-soluble bilirubinoids and biliverdinoids. Graphical abstract: [Figure not available: see fulltext.]
- Dey, Sanjeev K.,Lightner, David A.
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experimental part
p. 161 - 170
(2010/04/02)
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- A new route to porphyrins substituted with long alkoxy groups, attempts to prepare the discotic liquid crystals
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Pyrroles substituted with long alkoxy groups are prepared by the reaction of iminodiacetic acid dimethyl ester and dimethyl oxalate and the subsequent alkylation. These pyrroles are good precursor molecules for the corresponding porphyrins, which are expected to form an ordered columnar mesophase and are able to co-ordinate to various metals.
- Murashima, Takashi,Wakamori, Naoko,Uchihara, Yuki,Ogawa, Takujl,Uno, Hidemitsu,Ono, Noboru
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p. 165 - 171
(2007/10/03)
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- 3,4-Dialkoxypyrroles and 2,3,7,8,12,13,17,18-octaalkoxyporphyrins
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A five-step general synthesis of 3,4-dialkoxypyrroles 7c-f is described starting with the condensation of dimethyl N-benzyliminodiacetate (1 b) and diethyl oxalate to give dimethyl 1-benzyl-3,4-dihydroxypyrrole-2,5-dicarboxylate (2b), which is bis-O-alkylated to the corresponding 3,4-diethers 3c-g. Pyrrole N-benzyl cleavage followed by ester hydrolysis and decarboxylation leads to 7c-f in 10-50% overall yield. Pyrroles 7c-f react with formaldehyde or benzaldehydes to give meso-H- (8a-d) or meso-tetraaryloctaalkoxyporphyrins 9a-g in moderate yields.
- Merz,Schropp,Dotterl
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p. 795 - 800
(2007/10/02)
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