Attachment of histidine, histamine and urocanic acid to resins of the trityl-type (original) (raw)
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Regiospecific synthesis of 2, 3-disubstituted-L-histidines and histamines
2001
Regiospecific synthesis of 2, 3-disubstituted-l-histidines and 2, 3-disubstituted histamines starting from l-histidine methyl ester and histamine is reported. The key step involves homolytic free radical alkylation via silver catalyzed oxidative decarboxylation of alkylcarboxylic acids with ammonium persulfate.
Synthesis of 5-Alkynyl and 2,5-Dialkynyl-L-histidines
ChemistrySelect, 2022
Synthesis of previously unknown 5-alkynyl-L-histidines and 2,5dialkynyl-L-histidines is reported. Fully protected 5-iodo-and 2,5-diiodo-L-histidines obtained upon electrophilic iodination underwent cross-coupling alkynylation reaction with terminal alkynes in the presence of palladium-copper co-catalytic system to afford ring-modified histidines in 62-85 % yield. The method is also successfully utilized to late-stage alkynylate a 5iodohistidine residue containing peptide.
Journal of Labelled Compounds and Radiopharmaceuticals, 2013
Isotopologues of l‐histidine and its N‐methylderivatives labeled with deuterium and tritium at the 5‐position in the imidazole ring were obtained using the isotope exchange method. The deuterium‐labeled isotopologues [5‐2H]‐l‐histidine, [5‐2H]‐Nτ‐methyl‐l‐histidine, [5‐2H]‐Nπ‐methyl‐l‐histidine, and [2,5‐2H2]‐l‐histidine were synthesized by isotope exchange method carried out in a fully deuterated medium with. The same reaction conditions were applied to synthesize [5‐3H]‐Nτ‐methyl‐l‐histidine, [5‐3H]‐Nπ‐methyl‐l‐histidine, and [5‐3H]‐l‐histidine with specific activity of 2.0, 5.0, and 2.6 MBq/mmol, respectively. The Nπ‐[methyl‐14C]‐histamine was obtained with specific activity of 0.23 MBq/mmol in a one‐step reaction by the direct methylation of histamine by [14C]iodomethane.
The Journal of Organic Chemistry, 1991
0.25 mL were withdrawn at intervals and quenched into 1.5 mL of 95% ethanol. The solutions were centrifuged (13000g, 5 min), 0.5 mL of supernatant was added to 4 mL of glycine buffer (0.2 M, pH 10.4), and the absorbance at 540 nm was recorded. The reaction was allowed to proceed until no further change in A M was observed. The concentration of UDP-GlcUA was calculated from the difference between the final A M from solution 1 and the AM from solution 2, utilizing a molar absorbtivity for phenolphthalein at pH 10.4 of 38500 L mol-' cm-' . Acknowledgment. This work was supported by the NIH, grants GM30367 and GM39589. Registry No. UDP-Glc, 133-89-1; UDP-GlcUA, 2616-64-0;
Journal of Combinatorial Chemistry, 1999
The use of Phoxime resin 2 (phosgenated p-nitrophenyl(polystyrene)ketoxime) in the synthesis of acyclic and heterocyclic amino acid derived ureas is described. Resin 2 was previously shown to be a useful precursor in the solid-phase preparation of nonsymmetric ureas from thermolysis of corresponding primary amine oxime carbamates and subsequent trapping with an amine in solution. Generation of functionalized polymersupported primary amine oxime carbamates (3 and 9) for further diversification was accomplished by addition of amino acids or substituted hydrazines to resin 2. The use of these functionalized oxime carbamate resins for the generation of acyclic R-ureidoacetamides 5, 3-aminohydantoins 7, and 1,2,4-triazine-3,6-diones 8 is suitable for combinatorial library generation.
Facile regiospecific syntheses of N-α,N-1(τ)-dialkyl-l-histidines
Journal of Heterocyclic Chemistry, 2007
Two diverse methodologies describe the first synthesis of suitably protected N-,N-1()-dialkyl-Lhistidine derivatives. Synthesis of suitably protected N-,N-1()-dialkyl-L-histidines 7-9 containing different alkyl groups at the N-and N-1() positions was achieved in four steps starting from L-histidine methyl ester. Whereas, in the one-step alternate route N-Boc-L-histidine methyl ester upon direct and simultaneous N-and N-1() alkylation with various alkyl halides in the presence of sodium hydride in DMF easily afforded N-,N-1()-dialkyl-L-histidines 14 containing identical alkyl group at the N-and N-1() positions in high yields. Both procedures allowed facile entry to methyl and other higher alkyl groups at the N-position of the histidine ring
Organometallics, 2004
Sila-substitution (C/Si exchange) of one or both of the two quaternary carbon atoms of the histaminic H 1 antagonist terfenadine (1a) leads to sila-terfenadine-A (1b; R 3 COH f R 3 SiOH), sila-terfenadine-B (1c; R 4 C f R 4 Si), or disila-terfenadine (1d; R 3 COH f R 3 SiOH, R 4 C f R 4 Si). Sila-substitution of the quaternary carbon atom of the histaminic H 1 antagonist fexofenadine (2a) affords sila-fexofenadine (2b; R 3 COH f R 3 SiOH). The silicon compounds rac-1b, rac-1c, rac-1d, and rac-2b were synthesized in multistep syntheses, and the identities of these compounds and their precursors were established by elemental analyses and multinuclear NMR studies. Some of the precursors were additionally characterized by singlecrystal X-ray diffraction. The pharmacological profiles of rac-1a, rac-1b, rac-1c, rac-1d, rac-2a, and rac-2b were assessed across a range of histaminic receptor binding assays (radioligand binding studies at histamine central H 1 , peripheral H 1 , H 2 , and H 3 receptors). The silicon compounds, within experimental error, exhibited an affinity and selectivity profile similar to their corresponding carbon analogues.