- Visual Pigments. 11. Spectroscopy and Photophysics of Retinoic Acids and all-trans-Methyl Retinoate
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The photophysics of hydrogen-bonded complexes of retinoic acid and its 9-cis and 13-cis isomers and the photophysics of the dimers of these isomers of retinoic acid were studied.The ivestigation indicated that complexes of retinoic acid and molecules that
- Takemura, T.,Chihara, K.,Becker, Ralph S.,Das, P.K.,Hug, G.L.
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- Preparation method of olefine acid impurity
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The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of an olefine acid impurity. The impurity is (13E) -3, 7-dimethyl -9 -[(3RS) -3-methoxy -2, 6, 6-trimethyl cyclohexenyl] -2, 4, 6, 8-azela
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Paragraph 0054-0056
(2021/01/11)
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- Imidazotetrazines as Weighable Diazomethane Surrogates for Esterifications and Cyclopropanations
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Diazomethane is one of the most versatile reagents in organic synthesis, but its utility is limited by its hazardous nature. Although alternative methods exist to perform the unique chemistry of diazomethane, these suffer from diminished reactivity and/or correspondingly harsher conditions. Herein, we describe the repurposing of imidazotetrazines (such as temozolomide, TMZ, the standard of care for glioblastoma) for use as synthetic precursors of alkyl diazonium reagents. TMZ was employed to conduct esterifications and metal-catalyzed cyclopropanations, and results show that methyl ester formation from a wide variety of substrates is especially efficient and operationally simple. TMZ is a commercially available solid that is non-explosive and non-toxic, and should find broad utility as a replacement for diazomethane.
- Svec, Riley L.,Hergenrother, Paul J.
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supporting information
p. 1857 - 1862
(2019/12/27)
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- Novel retinoic acid metabolism blocking agents endowed with multiple biological activities are efficient growth inhibitors of human breast and prostate cancer cells in vitro and a human breast tumor xenograft in nude mice
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Novel retinoic acid metabolism blocking agents (RAMBAs) have been synthesized and characterized. The synthetic features include introduction of nucleophilic ligands at C-4 of all-trans-retinoic acid (ATRA) and 13-cis-retinoic acid, and modification of ter
- Patel, Jyoti B.,Huynh, Carlic K.,Handratta, Venkatesh D.,Gediya, Lalji K.,Brodie, Angela M. H.,Goloubeva, Olga G.,Clement, Omoshile O.,Nanne, Ivo P.,Soprano, Dianne Robert,Njar, Vincent C. O.
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p. 6716 - 6729
(2007/10/03)
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- Correlation of fluorescence quenching in carotenoporphyrin dyads with the energy of intramolecular charge transfer states. Effect of the number of conjugated double bonds of the carotenoid moiety
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The electrochemistry of a series of non-symmetric synthetic carotenoids, with different conjugated double bounds chain lengths (5 to 11) is reported. The values of the first oxidation potentials of the carotenoids were evaluated by digital simulation of t
- Fungo, Fernando,Otero, Luis,Durantini, Edgardo,Thompson, William J.,Silber, Juana J.,Moore, Thomas A.,Moore, Ana L.,Gust, Devens,Sereno, Leonides
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p. 469 - 475
(2007/10/03)
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- Potent inhibition of retinoic acid metabolism enzyme(s) by novel azolyl retinoids
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Novel (±)-4-azolyl retinoic acid analogues 4, 5, 7 and 8 have been designed and synthesized and have been shown to be powerful inhibitors of hamster microsomal all-trans-retinoic acid 4-hydroxylase enzyme(s). (±)-4-(1H-Imidazol-1-yl)retinoic acid (4) is t
- Njar, Vincent C.O.,Nnane, Ivo P.,Brodie, Angela M.H.
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p. 1905 - 1908
(2007/10/03)
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- A comprehensive survey of Stille-type C(sp2)-C(sp2) single bond forming processes in the synthesis of retinoic acid and analogs
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The synthesis of the retinoid skeleton has been exhaustively explored using the Stille coupling for the formation of the side- chain single bonds. On employing the experimental catalytic conditions developed by Farina [Pd2(dba)3, AsPh3, NMP] we have modified the electronic and steric requirement of the coupling partners, alkenyl stannanes and electrophiles (alkenyl iodides and triflates). The comprehensive survey afforded appropriately matched components for every bond formation considered. Moreover, from the comparison of the reactivities of different coupling partners with different degrees of steric hindrance, the sensitivity of the Stille coupling to steric effects was confirmed. Besides providing a variety of building blocks for retinoid synthesis, the study highlights some trends that might be useful for the application of the Stille reaction to the synthesis of unsubstituted conjugated polyenes.
- Dominguez, Beatriz,Iglesias, Beatriz,De Lera, Angel R.
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p. 15071 - 15098
(2007/10/03)
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- Preparation of 9-(Z)-retinoic acid
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A process for preparing 9-(Z)-retinoic acid from mother liquors from the industrial preparation of C15 -triarylphosphonium salts of the general formula I STR1 where R1 to R3 are each aryl and X? is halogen or (HSO4)?, in an organic solvent, which comprises A. increasing the proportion of 9-(Z)-C15 -triarylphosphonium salt in the C15 -triarylphosphonium salts isolated from the mother liquor by treatment with isopropanol at elevated temperature, cooling and separating off the all-(E)-C15 -triarylphosphonium salt which has crystallized out, B. subjecting the resulting C15 -triarylphosphonium salt to a Wittig reaction with an alkyl β-formylcrotonate of the general formula STR2 and C. hydrolyzing the resulting oily retinoic ester mixture in a C3 -C9 -alkanol, preferably in a propanol or butanol, precipitating the resulting 9-(Z)-retinoic acid where appropriate by adding methanol as crystals, with all-(E)-retinoic acid and other retinoic acid isomers remaining in the alkanolic solution.
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- Low-valent titanium reductive elimination: a direct and highly stereoselective synthesis of vitamin A aldehyde and all-trans retinoic acid orthothioester
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It is shown that low-valent titanium reductive elimination can be carried out in the presence of a thioacetal or an orthothioester group.The application to the synthesis of vitamin A aldehyde and all-trans retinoic acid orthothioester is described.Keywords - Ti(0) reductive elimination / vitamin A aldehyde / all-trans retinoic acid
- Solladie, G.,Berl, V.
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p. 568 - 574
(2007/10/02)
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- SYNTHETIC INVESTIGATIONS IN THE CHEMISTRY OF POLYENE COMPOUNDS LII. SYNTHESIS OF RETINOIC AND DIHYDRORETINOIC ESTERS BY THE REFORMATSKII REACTION
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The esters of 7,8- and 7,14-dihydroretinoic acids were obtained by the reaction of 6-methyl-8-(2,6,6-trimethyl-1-cyclohexenyl)-3,5-octadien-2-one with bromoacetic ester in the Reformatskii reaction followed by dehydration.The 7,8- and 7,14-dihydroretinoic
- Tutorskaya, O. O.,Miropol'skaya, M. A.,Samokhvalov, G. I.
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p. 1237 - 1240
(2007/10/02)
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- Assignment of 1H and 13C NMR Spectra of Retinoic Acid Ester Isomers Observed in the Long-Wavelength UV-Induced Photostationary State
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1H and 13C chemical shift assignments, obtained with the aid of two-dimensional hetenuclear shift correlation and double-quantum coherence 13C-INADEQUATE experiments, are reported for four retinoic acid ester isomers observed at the photostationary state.Also detailed are 1H assignments for three additional isomers obtained in insufficient amounts for 13C measurements.KEY WORDS - Retionic acid esters Isomer identification 1H-13C correlation spectra 13C-INADEQUATE experiment
- Curley, Robert W.,Fowble, John W.
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p. 707 - 709
(2007/10/02)
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- Synthesis of retinals labelled at positions 14 and 15 (with 13C and/or 2H)
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Eight retinals labelled at positions 14 and 15 with 13C and/or 2H were obtained with 98 percent chemical purity, 92 percent 13C incorporation, 95 percent 2H incorporation at position 14 and 99 percent 2H incorporation at position 15. (14-13C)retinal, (15-13C)retinal and (14,15-13C)retinal were synthesized from (2-13C)-, (1-13C)- and (1,2-13C)acetonitrile, respectively, while for the synthesis of (14-2H)retinal, 2CH3CN was used.Via a three-step process these retinals were transformed into (14,15-2H)retinal, (14-13C,15-2H)retinal, (15-13C,15-2H)retinal and (14,15-13C2,15-2H)retinal.Their 13C-13C, 13C-2H and 13C-H NMR coupling constants were determined.
- Pardoen, J. A,Winkel, C,Mulder, P.P.J,Lugtenburg, J
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p. 135 - 141
(2007/10/02)
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- A CONVENIENT AND IMPROVED METHOD FOR THE PREPARATION OF RETINOATES
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The reaction of various alcohols with retinoic acid in the presence of N,N'-dicyclohexylcarbodiimide affords the corresponding retinoates in good yields.
- Singh, Anil K.
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p. 447 - 452
(2007/10/02)
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- NEW MASKED BUILDING BLOCK FOR ISOPRENOID POLYENE CHAIN SYNTHESIS
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The new building blocks 2, 3, and 4 have been effectively synthesized starting from 2-hydroxymethyl-4-phenylthio-1-butene (1a).A convenient synthesis of retinoic acid methyl ester (9) using 2 is also described.
- Mandai, T.,Iuchi, Y.,Suzuki, K.,Kawada, M.,Otera, J.
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p. 4721 - 4724
(2007/10/02)
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- Transient Phenomena in the Pulse Radiolysis of Retinyl Polyenes. 1. Radical Anions
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The spectra and kinetics of formation and decay of radical anions of a number of retinyl polyenes have been studied in methanol and 2-propanol at room temperature, using pulse radiolysis and kinetic spectrophotometry.The bimolecular rate constants for the attachment of solvated electrons, e-MeOH, to the retinyl polyenes are in the diffusion-controlled limit (8.6 x 109-1.6 x 1010 M-1 s-1).The radical anions of retinol and retinol acetate have their spectral maxima at 370-390 nm, and undergo decay very slowly with second-order kinetics.On the other hand, the radical anions of retinal, retinal n-butylamine Schiff base, and retinoic acid/ester have spectral maxima at 430-510 nm, and decay by first-order kinetics in methanol with rate constants in the range 1 x 104-1 x 106 s-1.The decay rates of radical anions of retinal and retinoic acid/ester become considerably longer on going from methanol to less acidic alcohol, 2-propanol, suggesting that protonation by solvent is the major mode of their decay in protic media.In the case of retinal Schiff base, an additional slow process with bimolecular rate constant 9.0 x 107 M-1 s-1 im methanol is observed for the formation of radical anion and is ascribed to the electron-transfer reaction from the methanol radical, .CH2OH.
- Raghavan, N.V.,Das, P.K.,Bobrowski, K.
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p. 4569 - 4573
(2007/10/02)
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