138455-22-8Relevant articles and documents
N-alkylation of purines with alkyl esters of phosphorus oxy acids.
Yamauchi,Hayashi,Kinoshita
, p. 385 - 386 (1975)
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A novel method of caffeine synthesis from uracil
Zajac, Matthew A.,Zakrzewski, Anthony G.,Kowal, Mark G.,Narayan, Saraswathi
, p. 3291 - 3297 (2003)
An inexpensive and novel method of caffeine synthesis starting from uracil in six simple steps is described. Uracil 1 is first converted to I, 3-dimethyluracil 2, followed by nitration, reduction, and cyclization to theophylline and finally methylation of theophylline forms caffeine.
N-alkylation of pyrimidine and purine derivatives (uracils, xanthines, adenine) using solid/liquid phase-transfer catalysis without solvent
Bram,Decodts,Bensaid,et al.
, p. 543 - 545 (1985)
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Fillippos'yants et al.
, (1968)
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Trimethylsulfonium Fluoride and n-Butyldimethylsulfonium Fluoride: New Methylating Agents for Nucleosides and Related Compounds
Yamauchi, Kiyoshi,Hisanaga, Yorisato,Kinoshita, Masayoshi
, p. 852 - 853 (1980)
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Molecular and biochemical characterization of caffeine synthase and purine alkaloid concentration in guarana fruit
Schimpl, Flávia Camila,Kiyota, Eduardo,Mayer, Juliana Lischka Sampaio,Gon?alves, José Francisco De Carvalho,Da Silva, José Ferreira,Mazzafera, Paulo
, p. 25 - 36 (2014)
Guarana seeds have the highest caffeine concentration among plants accumulating purine alkaloids, but in contrast with coffee and tea, practically nothing is known about caffeine metabolism in this Amazonian plant. In this study, the levels of purine alkaloids in tissues of five guarana cultivars were determined. Theobromine was the main alkaloid that accumulated in leaves, stems, inflorescences and pericarps of fruit, while caffeine accumulated in the seeds and reached levels from 3.3% to 5.8%. In all tissues analysed, the alkaloid concentration, whether theobromine or caffeine, was higher in young/immature tissues, then decreasing with plant development/maturation. Caffeine synthase activity was highest in seeds of immature fruit. A nucleotide sequence (PcCS) was assembled with sequences retrieved from the EST database REALGENE using sequences of caffeine synthase from coffee and tea, whose expression was also highest in seeds from immature fruit. The PcCS has 1083 bp and the protein sequence has greater similarity and identity with the caffeine synthase from cocoa (BTS1) and tea (TCS1). A recombinant PcCS allowed functional characterization of the enzyme as a bifunctional CS, able to catalyse the methylation of 7-methylxanthine to theobromine (3,7-dimethylxanthine), and theobromine to caffeine (1,3,7-trimethylxanthine), respectively. Among several substrates tested, PcCS showed higher affinity for theobromine, differing from all other caffeine synthases described so far, which have higher affinity for paraxanthine. When compared to previous knowledge on the protein structure of coffee caffeine synthase, the unique substrate affinity of PcCS is probably explained by the amino acid residues found in the active site of the predicted protein.
Mechanistic Insight into Caffeine-Oxalic Cocrystal Dissociation in Formulations: Role of Excipients
Duggirala, Naga Kiran,Vyas, Amber,Krzyzaniak, Joseph F.,Arora, Kapildev K.,Suryanarayanan, Raj
, p. 3879 - 3887 (2017)
Caffeine-oxalic acid cocrystal, widely reported to be stable under high humidity, dissociated in the presence of numerous pharmaceutical excipients. In cocrystal-excipient binary systems, the water mediated dissociation reaction occurred under pharmaceutically relevant storage conditions. Powder X-ray diffractometry was used to identify the dissociated products obtained as a consequence of coformer-excipient interaction. The proposed cocrystal dissociation mechanism involved water sorption, dissolution of cocrystal and excipient in the sorbed water, proton transfer from oxalic acid to the excipient, and formation of metal salts and caffeine hydrate. In compressed tablets with magnesium stearate, the cocrystal dissociation was readily discerned from the appearance of peaks attributable to caffeine hydrate and stearic acid. Neutral excipients provide an avenue to circumvent the risk of water mediated cocrystal dissociation.
SERS multiplexing of methylxanthine drug isomersviahost-guest size matching and machine learning
Chio, Weng-I Katherine,Dinish, U. S.,Jones, Tabitha,Lee, Tung-Chun,Liu, Jia,Olivo, Malini,Parkin, Ivan P.,Perumal, Jayakumar
supporting information, p. 12624 - 12632 (2021/10/06)
Multiplexed detection and quantification of structurally similar drug molecules, methylxanthine MeX, incl. theobromine TBR, theophylline TPH and caffeine CAF, have been demonstratedviasolution-based surface-enhanced Raman spectroscopy (SERS), achieving highly reproducible SERS signals with detection limits down to ～50 nM for TBR and TPH, and ～1 μM for CAF. Our SERS substrates are formed by aqueous self-assembly of gold nanoparticles (Au NPs) and supramolecular host molecules, cucurbit[n]urils (CBn,n= 7, 8). We demonstrate that the binding constants can be significantly increased using a host-guest size matching approach, which enables effective enrichment of analyte molecules in close proximity to the plasmonic hotspots. The dynamic range and the robustness of the sensing scheme can be extended using machine learning algorithms, which shows promise for potential applications in therapeutic drug monitoring, food processing, forensics and veterinary science.
Dehydroxymethylation of alcohols enabled by cerium photocatalysis
Zhang, Kaining,Chang, Liang,An, Qing,Wang, Xin,Zuo, Zhiwei
supporting information, p. 10556 - 10564 (2019/08/20)
Dehydroxymethylation, the direct conversion of alcohol feedstocks as alkyl synthons containing one less carbon atom, is an unconventional and underexplored strategy to exploit the ubiquity and robustness of alcohol materials. Under mild and redox-neutral reaction conditions, utilizing inexpensive cerium catalyst, the photocatalytic dehydroxymethylation platform has been furnished. Enabled by ligand-to-metal charge transfer catalysis, an alcohol functionality has been reliably transferred into nucleophilic radicals with the loss of one molecule of formaldehyde. Intriguingly, we found that the dehydroxymethylation process can be significantly promoted by the cerium catalyst, and the stabilization effect of the fragmented radicals also plays a significant role. This operationally simple protocol has enabled the direct utilization of primary alcohols as unconventional alkyl nucleophiles for radical-mediated 1,4-conjugate additions with Michael acceptors. A broad range of alcohols, from simple ethanol to complex nucleosides and steroids, have been successfully applied to this fragment coupling transformation. Furthermore, the modularity of this catalytic system has been demonstrated in diversified radical-mediated transformations including hydrogenation, amination, alkenylation, and oxidation.
