- Synthesis and biological evaluation of potent, selective, hexapeptide CCK-A agonist anorectic agents
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Cholecystokinin (CCK) is a 33-amino acid peptide with multiple functions in both the central nervous system (via CCK-B receptors) and the periphery (via CCK-A receptors). CCK mediation of satiety via the A-receptor subtype suggest a role for CCK in the ma
- Pierson,Comstock,Simmons,Kaiser,Julien,Zongrone,Rosamond
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p. 4302 - 4307
(2007/10/03)
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- Amino acids and peptides. LI. Application of the 2- adamantyloxycarbonyl (2-Adoc) group to the protection of the hydroxyl function of tyrosine in peptide synthesis
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A 2-adamantyloxycarbonyl (2-Adoc) group was introduced as a protecting group for the hydroxyl function of tyrosine (Tyr) through the Shotten- Bauman reaction of 2-adamantyloxycarbonyl chloride with the copper complex of Tyr. The 2-Adoc group is stable to trifluoroacetic acid (TFA), 5.0 N HCl/dioxane, hydrogenation over a Pd catalyst and tertiary amine, and is easily removed by treatment with 1M trifluoromethanesulfonic acid (TFMSA)- thioanisole/TFA and HF. Boc-Tyr(2-Adoc)-OH was prepared by the reaction of (Boc)2O and H-Tyr(2-Adoc)-OH in the presence of triethylamine. Boc-Tyr(2- Adoc)-OH was successfully applied to the synthesis of Boc-Ala-Thr-Val- Lys(2-Adoc)-Phe-Lys(2-Adoc)-Tyr(2-Adoc)-Gly-OH, corresponding to the sequence 1-9 of Sulfolobus solfataricus RNase, and Boc-Tyr(2-Adoc)-Asp(O- 2-Ada)-Glu(O-cHex)-Gly-OH, corresponding to the sequence 33-36 of S. solfataricus RNase. Boc-Phe-Lys(2-Adoc)-Tyr(2-Adoc)-Lys(2-Adoc)-Gly-OBzl was treated with anhydrous HF to afford H-Phe-Lys-Tyr-Gly-OH without any side reactions, in a good yield.
- Okada, Yoshio,Shintomi, Noriyuki,Kondo, Yukihiro,Yokoi, Toshio,Joshi, Shima,Wei
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p. 1860 - 1864
(2007/10/03)
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