18822-59-8Relevant articles and documents
A N-(9-fluorenylmethyloxycarbonyl)-O-tert-butyl-L-tyrosine method for the preparation of
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, (2017/04/11)
The invention relates to a method for preparing N-(9-fluorenylmethoxy carbony)-O-tertiary butyl-L-tyrosine. The problem that an enantiomer is easily generated is solved. The method comprises the following synthetic steps: (1) dissolving L-Tyr into a methanol solution, adding SOCl2 and then carrying out reflux reaction, so as to obtain Tyr-OMe.HCl; (2) dissolving the Tyr-OMe.HCl into a water solution, adding AcOEt and Na2CO3 and then reacting with Z-Cl, and controlling the pH of the system at 7-10, so as to obtain Z-L-Tyr-OMe; (3) dissolving the Z-L-Tyr-OMe into a CH2Cl2 solution, adding H2SO4 and isobutene, reacting at normal temperature for 1-10 days, so as to obtain Z-L-Tyr(tBu)-OMe; (4) adding the NaOH solution to the Z-L-Tyr(tBu)-OMe to react, so as to obtain Z-L-Tyr(tBu); (5) dissolving the Z-L-Tyr(tBu) into methanol, adding Pd/C, and leading in hydrogen to react, so as to obtain L-Tyr(tBu); (6) dissolving Z-L-Tyr(tBu) into the water solution, adding the Na2CO3 and THF and then reacting with Fmoc-osu, and controlling the pH of the system at 8-10, so as to obtain Fmoc-Tyr(tBu). By adopting the method, generation of the enantiomer is avoided, and the citric acid is taken as an acidifier, so that the product is more stable, and the reaction processes do not relate to high-temperature and high-pressure reaction, and the method is applicable to large-scale production.
Selective Deprotection of the Nα-tert-Butyloxycarbonyl Group in Solid Phase Peptide Synthesis with Chlorotrimethylsilane and Phenol
Kaiser, Emil Sr.,Picart, Francis,Kubiak, Teresa,Tam, James P.,Merrifield, R. B.
, p. 5167 - 5175 (2007/10/02)
The repetitive deprotection of the Nα-tert-butyloxycarbonyl group during solid phase peptide synthesis was found to be efficient and quantitative by use of a mild new reagent containing 1 M chlorotrimethylsiane and 1 M phenol in dichloromethane.Kinetic studies showed that the half-life for the reaction at 22 deg C with Boc-Val-resin was 17.5 min, a 40-fold increase over the rate in the absence of phenol.The reaction is not due to the presence of HCl in the reagent.The selectivity between the removal at the Nα-tert-butyloxycarbonyl group and benzylic esters, ethers, and carbonate side chain protecting groups was >1E5 and relative to the anchoring benzyl ester bond to the resin support it was 6E3.This is a marked improvement over the selectivity of the conventional 50percent trifluoroacetic acid in CH2Cl2 deprotecting agent and significantly reduces the accumulated byproducts resulting from losses of benzylic groups.The cleavage of the tert-butyl urethane was first order in Me3SiCl and second order in C6H5OH.The preferred reagent is 1 M Me3SiCl-3 M C6H5OH-CH2Cl2 and the deprotection time is 20 min (t1/2 = 1.8 min for Boc-Val-OCH2-resin).Evidence for the mechanism of the reaction was deduced.Several peptides, including Leu-enkephalin, -angiotensin II, and glucagon were successfully synthesized in high yields and excellent purity by the stepwise solid phase method using this new reagent.
