107326-87-4

Upstream product

• 65864-24-6 Boc-Nle-Asp(OBzl)-Phe-NH₂ 
• 76-05-1 trifluoroacetic acid 

Downstream Products

• 136015-52-6 (S)-3-[(S)-2-((S)-2-tert-Butoxycarbonylamino-3-naphthalen-1-yl-propionylamino)-hexanoylamino]-N-((S)-1-carbamoyl-2-phenyl-ethyl)-succinamic acid benzyl ester 
• 120085-36-1 C₆₈H₈₉N₁₁O₁₄ 
• 120085-39-4 C₆₈H₈₉N₁₁O₁₄ 
• 107326-92-1 Boc-Tyr-Nle-D-Lys(Z)-Trp-Nle-Asp(OBzl)-Phe-NH₂ 
• 107326-88-5 C₆₇H₈₇N₁₁O₁₄ 
• 136794-01-9 (S)-3-[(S)-2-((S)-2-tert-Butoxycarbonylamino-3-naphthalen-2-yl-propionylamino)-hexanoylamino]-N-((S)-1-carbamoyl-2-phenyl-ethyl)-succinamic acid benzyl ester 
• 117903-30-7 Boc-Trp-Nle-Asp(OBzl)-Phe-NH₂ 

Relevant academic research and scientific papers

CCK-B agonist or antagonist activities of structurally hindered and peptidase-resistant Boc-CCK4 derivatives

Replacement of Met31 by (N-Me)Nle in CCK8 or CCK4 has been shown to improve the affinity and selectivity for CCK-B receptors. In order to obtain molecules with enhanced bioavailability, two novel series of protected tetrapeptides of the general formula Boc-Trp30-X-Asp-Y33 have been developed. Introduction of (N-Me)Nle and the bulky, aromatic naphthylalaninamide (Nal-NH2) in positions X and Y, respectively, does not greatly modify the affinity for guinea pig brain CCK-B receptors. In contrast, incorporation of hindering N-methyl amino acids such as (N-Me)Phe, (N-Me)Phg, or (N-Me)Chg, but not their non-methylated counterparts, in position X induced a large decrease in affinity for the CCK-B binding sites. Among the various peptides synthesized, Boc-[(N-Me)Nle31,1Nal- NH233]CCK4 (2) (K(I) = 2.8 nM), Boc-[Phg31,1Nal-NH233]CCK4 (15) (K(I) = 14 nM), and Boc-[Phg31,1Nal-N(CH3)233]CCK4 (17) (K(I) = 39 nM) displayed good affinities for brain CCK-B receptors and had good selectivity ratios. These pseudopeptides, in which the presence of unnatural and hydrophobic residues is expected to improve their penetration of the central nervous system, were shown to be very resistant to brain peptidases. Interestingly, whereas compounds 2 and 15 proved to be full agonists for rat hippocampal CCK-B receptors when measured in an electrophysiological assay, compound 17 behaved as a potent antagonist in the same test and displayed a good affinity in rat brain K(I)(CCK-B) = 51 nM as compared to the Merck antagonist L365,260, K(I)(CCK-B) = 12 nM. This illustrates a simple means to obtain CCK-B antagonists and suggests that the free, CONH2 group plays a critical role in the recognition of the agonist state of brain CCK-B receptors.

Synthesis and biological activities of cholecystokinin analogues substituted in position 30 by 3-(1-naphthyl)-L-alanine [Nal(1)] or 3-(2-naphthyl)-L-alanine [Nal(2)]

Acetyl derivatives of ethyl esters of 3-(1-naphthyl)-D,L-alanine and 3-(2-naphthyl)-D,L-alanine were synthesized through a malonic condensation. Resolution of these derivatives by subtilisin Carlsberg followed by acid hydrolysis afforded the 2 optical isomers of 3-(1-naphthyl)-alanine [Nal(1)] and 3-(2-naphthyl)-alanine [Nal(2)]. The L enantiomers of these amino acids were incorporated into the sequence of cholecystokinin in place of the tryptophan in position 30. The cholecystokinin analogues thus obtained behaved as full agonists, with reduced potencies on rat pancreatic acini and on guinea pig brain membranes, by about one order of magnitude for the Nal(1) derivative, as compared to the potent parent compound Boc-Tyr(SO3H)-Nle-Gly-Trp-Nle-Asp-Phe-NH2.