Identification and optimisation of novel sulfonamide, selective vasopressin V1B receptor antagonists

The synthesis and preliminary structure-activity relationships (SAR) of a novel class of vasopressin V(1B) receptor antagonists are described. Hit compound 5, identified via high throughput screening of the corporate collection, showed good activity in a V(1B) binding assay (K(i) 63 nM) but did not possess the lead-like physicochemical properties typically required in a hit compound. A 'deletion approach' on the HTS hit 5 was performed, with the focus on improvement of physicochemical properties, yielding the selective V(1B) antagonist 9f (K(i) 190 nM), with improved druglike characteristics.     

Synthesis and biological evaluation of novel indoloazepine derivatives as non-peptide vasopressin V2 receptor antagonists

A series of novel 3,4,5,6-tetrahydro-1H-azepino[4,3,2-cd]indoles was synthesized and tested for vasopressin receptor antagonist activity. We identified compounds with high affinity for the human V2 receptor and good selectivity over the human V1a receptor. Compound 6c bound to V2 receptors with an IC(50) value of 20 nM, had >100-fold selectivity over V1a receptors, and inhibited cAMP formation in a cellular V2 functional assay with an IC(50) value of 70 nM.     

The design and synthesis of novel NK1/NK2 dual antagonists

Functional probing of the backbone of the Sanofi NK2 antagonist SR 48968 has resulted in the discovery of two new classes of NK1/NK2 dual antagonists: the diamine class and the oxime class. The addition of the amino or the oxime functional group results in the reversal of the stereochemical preference of the NK2 receptor.     

An optimized chemical synthesis of human relaxin‐2

Human gene 2 relaxin (RLX) is a member of the insulin superfamily and is a multi‐functional factor playing a vital role in pregnancy, aging, fibrosis, cardioprotection, vasodilation, inflammation, and angiogenesis. RLX is currently applied in clinical trials to cure among others acute heart failure, fibrosis, and preeclampsia. The synthesis of RLX by chemical methods is difficult because of the insolubility of its B‐chain and the required laborious and low yielding site‐directed combination of its A (RLXA) and B (RLXB) chains. We report here that oxidation of the Met²⁵ residue of RLXB improves its solubility, allowing its effective solid‐phase synthesis and application in random interchain combination reactions with RLXA. Linear Met(O)²⁵‐RLX B‐chain (RLXBO) reacts with a mixture of isomers of bicyclic A‐chain (bcRLXA) giving exclusively the native interchain combination. Applying this method Met(O)²⁵‐RLX (RLXO) was obtained in 62% yield and was easily converted to RLX in 78% yield, by reduction with ammonium iodide. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.     

Structure-based design, synthesis, and biological evaluation of novel 1,4-diazepines as HDM2 antagonists

Crystallographic analysis of ligands bound to HDM2 suggested that 7-substituted 1,4-diazepine-2,5-diones could mimic the alpha-helix of p53 peptide and may represent a promising scaffold to develop HDM2-p53 antagonists. To verify this hypothesis, we synthesized and biologically evaluated 5-[(3S)-3-(4-chlorophenyl)-4-[(R)-1-(4-chlorophenyl)ethyl]-2,5-dioxo-7-phenyl-1,4-diazepin-1-yl]valeric acid (10) and 5-[(3S)-7-(2-bromophenyl)-3-(4-chlorophenyl)-4-[(R)-1-(4-chlorophenyl)ethyl]-2,5-dioxo-1,4-diazepin-1-yl]valeric acid (11). Preliminary in vitro testing shows that 10 and 11 substantially antagonize the binding between HDM2 and p53 with an IC(50) of 13 and 3.6 microM, respectively, validating the modeling predictions. Taken together with the high cell permeability of diazepine 11 determined in CACO-2 cells, these results suggest that 1,4-diazepine-2,5-diones may be useful in the treatment of certain cancers.     

Synthesis and some pharmacologic properties of five novel V1 or V1/V2 antagonists of AVP

Based on [1-(1-mercaptocyclohexaneacetic acid),2-(O-ethyl-D-tyrosine),4-valine]-8-arginine-vasopressin as a model, five new analogues of arginine-vasopressin (AVP) were designed and synthesized. Four of them have in position 1 a large lipophilic substituent, whereas the fifth contains pchloro-D-phenylalanine at position 2. We found that the anti-antidiuretic potency with 1-mercapto-4-methycyclohexaneacetic acid is higher than with 1-mercaptocyclohexaneacetic acid (model peptide) in position 1 and this analogue is among the most potent antagonists of the antidiuretic response to AVP known to date. Upon further increase of the size of substituents, antagonistic potency was significantly decreased or totally eliminated. As for the substitution of p-chloro-D-phenylalanine in position 2, we conclude that this modification leads to substantial decrease of the V2 antagonistic potency.     

Identification,design and synthesis of novel pyrazolopyridine influenza virus nonstructural protein 1 antagonists

Nonstructural protein 1 (NS1) plays a crucial function in the replication, spread, and pathogenesis of influenza virus by inhibiting the host innate immune response. Here we report the discovery and optimization of novel pyrazolopyridine NS1 antagonists that can potently inhibit influenza A/PR/8/34 replication in MDCK cells, rescue MDCK cells from cytopathic effects of seasonal influenza A strains, reverse NS1-dependent inhibition of IFN-β gene expression, and suppress the slow growth phenotype in NS1-expressing yeast. These pyrazolopyridines will enable researchers to investigate NS1 function during infection and how antagonists can be utilized in the next generation of treatments for influenza infection.     

人干细胞因子cDNA的设计、合成与克隆

选择大肠杆菌的偏爱密码子,分成18个长约60个碱基且相互配对的寡核苷酸片段,合成了可溶形式的人干细胞因子（hSCF)的cDNA,合成片段经纯化、5′-端磷酸化后,通过PCR进行合成hSCF的cDNA一次性组装与扩增,得到了含有可溶形式的hSCF的全部编码区及EcoRⅠ、SalⅠ位点在内的全长共515个碱基对的DNA片段,回收该DNA片段,酶切消化,定向克隆进质粒pUC19。经酶切鉴定以及序列测定,得到了全序列正确的克隆株,为下一步的工作奠定了基础。     

The pharmacology of burimamide and metiamide, two histamine H2-receptor antagonists.

Burimamide and metiamide are two histamine H2-receptor antagonists. Evidence is presented that indicates the competitive nature and the specificity of the antagonism. Metiamide is about ten times more potent than burimamide and is also more effective than burimamide when given orally. Both compounds inhibit gastric secretion and the evidence is consistent with this inhibition being due to competitive antagonism of H2 receptors in the gastric mucosa. Burimamide, unlike metiamide, causes release of catecholamines even at dose levels that are just sufficient to produce H2-receptor antagonism. Burimamide, but not metiamide, has alpha-adrenoceptor blocking activity. In certain models for inflammation, particularly rat paw edema induced by compound 48/80, burimamide in combination with the H1-receptor antagonist mepyramine shows anti-inflammatory activity. This may, in part, be associated with the catecholamine-releasing properties of the compound. Metiamide is less active in this respect.     

The physical and chemical properties of eumelanin

In this article, we review the current state of knowledge concerning the physical and chemical properties of the eumelanin pigment. We examine properties related to its photoprotective functionality, and draw the crucial link between fundamental molecular structure and observable macroscopic behaviour. Where necessary, we also briefly review certain aspects of the pheomelanin literature to draw relevant comparison. A full understanding of melanin function, and indeed its role in retarding or promoting the disease state, can only be obtained through a full mapping of key structure-property relationships in the main pigment types. We are engaged in such an endeavor for the case of eumelanin.     

The design and synthesis of novel, phosphonate-containing transient receptor potential melastatin 8 (TRPM8) antagonists

A series of benzothiophene-based phosphonates was synthesized and many analogs within the series were shown to be potent antagonists of the TRPM8 channel. The compounds were obtained as a racemic mixture in 5 synthetic steps, and were tested for TRPM8 antagonist activity in a recombinant, canine TRPM8-expressing cell line using a fluorometric imaging plate reader (FLIPR) assay. Structure-activity relationships were developed initially by modification of the core structure and subsequently by variation of the aromatic substituents and the phosphonate ester. Compound 9l was administered intraperitoneally to rats and demonstrated engagement of the TRPM8 target in both prevention and reversal-modes in an icilin-induced 'wet-dog' shake model.     

The design and synthesis of novel, potent and orally bioavailable N-aryl piperazine-1-carboxamide CCR2 antagonists with very high hERG selectivity

A novel N-aryl piperazine-1-carboxamide series of human CCR2 chemokine receptor antagonists was discovered. Early analogues were potent at CCR2 but also inhibited the hERG cardiac ion channel. Structural modifications which decreased lipophilicity and basicity resulted in the identification of a sub-series with an improved margin over hERG. The pharmacological and pharmacokinetic properties of the lead compound from this series, N-(3,4-dichlorophenyl)-4-[(2R)-4-isopropylpiperazine-2-carbonyl]piperazine-1-carboxamide, are described.     

Identification and synthesis of major metabolites of Vasopressin V2-receptor agonist WAY-151932, and antagonist, Lixivaptan

Small molecule agonists and antagonists of the V(2)-vasopressin receptor have been discovered and have undergone clinical trials. In conjunction with these discovery programs, the synthesis and biological testing of various metabolites associated with these clinical targets were actively pursued. We now report the results of our synthetic efforts and the corresponding biological data generated for several of the metabolites of WAY-151932 and CL-347985 (Lixivaptan).     

Analogues and derivatives of ciproxifan, a novel prototype for generating potent histamine H3-receptor antagonists

Novel derivatives of the highly potent and selective histamine H3-receptor antagonist ciproxifan (3) with different chain lengths as well as with structural variants of the cyclopropyl ketone moiety have been prepared and screened for their antagonist H3-receptor potencies in vitro and in vivo. Some derivatives (2, 6-8, 12) containing other functionalities were effective in vitro in the same (sub)nanomolar concentration range and in vivo in a remarkably low oral dose.     

Novel linear antagonists of the antidiuretic (V2) and vasopressor (V1) responses to vasopressin

We report the solid phase synthesis of a series of 16 linear analogues of the cyclic antagonist of the antidiuretic (V2) and the vasopressor (V1) responses to arginine vasopressin (AVP), d(CH2)5[D-Tyr(Et)2, Val4]AVP(A). Peptide 1, the linear precursor of (A), (CH2)5(SH)-CH2-CO-D-Tyr(Et)-Phe-Val-Asn-Cys-Pro-Arg-Gly-NH2 was modified at position six with alpha-L-aminobutyric acid (Abu) to give peptide 2. Further modifications of the Abu6 analogue (No. 2) at position one by substituting cyclohexylacetic acid (Caa), cyclohexylpropionic acid (Cpa), 1-adamantaneacetic acid (Aaa), phenylacetic acid (Phaa), tert.-butylacetic acid (t-Baa), isovaleric acid (Iva), propionic acid (Pa), L-penicillamine (P), tert.-butoxycarbonyl (Boc) or omitting any substituent at this position, and/or in combination with Arg-NH2(9), Ala-NH2(9), D-Arg8-Arg-NH2(9), and desGly9 modifications yielded the remaining 14 peptides. All 16 peptides were examined for agonistic and antagonistic potencies in AVP V2 and V1 assays in rats. Apart from the Cpa analogue and the analogue lacking any substituent in the 1-position, all exhibit substantial V2 and V1 antagonism. A number are as potent as (A) as V2 antagonists. With an anti-V2 pA2 = 8.11 +/- 0.07, Aaa-D-Tyr(Et)-Phe-Val-Asn-Abu-Pro-Arg-Arg-NH2 (No. 6) is as potent as any cyclic AVP V2 antagonist reported to date. The PaI analogue of No. 6 exhibits promising anti-V2/anti-V1 selectivity. These findings prove conclusively that a ring structure is not a requirement for recognition of or for binding to AVP V2 or V1 receptors. This discovery thus offers a promising new approach to the design of peptide and non-peptide antagonists of AVP and perhaps also to other cyclic peptides such as somatostatin, atrial-natriuretic factor, insulin, and the recently discovered endothelin. Some of these linear antagonists may be of value as pharmacological tools and as therapeutic agents.     

A comparative study of plasma vasopressin levels and V1 and V2 vasopressin receptor properties in congenital hypothyroid rat under thyroxine or vasopressin therapy

The effects of propylthiouracil (PTU) treatment on the plasma vasopressin level, on the number of hepatic (V1) or renal (V2) vasopressin receptors and on the hormone-sensitive adenylate cyclase activity in the kidney of developing rats were studied in parallel. In addition, we investigated the corrective effects of thyroxine therapy on the plasma vasopressin level and parameters related to the liver, and the effects of vasopressin therapy on the parameters related to the kidney. As already reported in the case of the number of V2 receptors and adenylate cyclase activity in the kidney, the deficient plasma vasopressin level in hypothyroid rats was completely corrected by two daily physiological doses of thyroxine given from birth to the age of sacrifice (1 month). Unlike the V1 receptors, the V2 receptors are known to be highly dependent on their specific circulating ligand. Since, first of all, the deficit was similar in the numbers of V1 and V2 receptors in hypothyroid rats, and, secondly, the treatment of hypothyroid rats by two daily physiological doses of long lasting vasopressin was found ineffective to recover the deficit in the number of V2 receptors, it can be concluded that thyroid deficiency directly alters vasopressin receptor biosynthesis in both liver and kidney, instead of acting via the depressed plasma vasopressin level.     

Beta-carboline-carbohydrate hybrids: molecular design, chemical synthesis and evaluation of novel DNA photocleavers

Beta-carboline present in beta-carboline alkaloids from marine organisms was found, for the first time, to cleave DNA at the guanine site upon irradiation with UV light with a long wavelength without any additive, and beta-carboline-carbohydrate hybrid system was effective for DNA cleavage.