2,6-Methano-3-benzazocine-11-ropanols. Lack of antagonism between optical antipodes and observation of potent narcotic antagonism by two n-methyl derivatives.

Resolution of a 2,6-methano-3-benzazocine-11-propanol analogue of buprenorphine showed that the biological activity resides in the levo antipode. An attempt to enhance agonist activity by preparation of N-methyl derivatives resulted in two compounds three and five times as potent as nalorphine as antagonists of phenazocine. These compounds are the most potent N-methyl narcotic antagonists reported to date.

Benzomorphans. Structure of a position isomer.

May's benzomorphan synthesis leads not only to the alpha or cis isomer and the beta or trans isomer but also to a position isomer hereinafter called the gamma isomer. The structure and synthesis of this isomer are described. Biological activities of the alpha and gamma isomers are compared.

Synthesis and narcotic agonist-antagonist evaluation of some 2,6-methano-3-benzazocine-11 propanols. Analogues of the ring C bridged oripavine-7-mehtanols.

A general synthesis of variously substituted 2,6-methano-3-benzazocine-11-propanols is described. Nine N-CH3 derivatives and their corresponding N-cyclopropylmethyl counterparts were prepared and studied in the mouse acetylcholine induced writhing and rat phenazocine antagonism tests. The results are compared with literature information on the bridged oripavine methanols. It is concluded that the synthetic analogues have a different structure-activity profile, in general being weak agonists but potent antagonists.

(2,6-Methano-3-benzazocin-11 beta-yl)alkanones. 1. Alkylalkanones: a new series of N-methyl derivatives with novel opiate activity profiles.

A general stereospecific synthesis of (N-methyl-2,6-methano-3-benzazocin-11 beta-yl)alkanones is described and applied to the preparation of a series of alkyl ketones wherein the alkyl group is a straight or terminally branched chain containing from one to six carbon atoms. Several compounds with methoxy groups in the aromatic ring are in the morphine range of potency; they are uniformly inactive as phenazocine antagonists. Phenolic analogues range up to 100 times as potent as morphine. Those containing five or six carbon atoms in the alkyl group exhibit phenazocine antagonist activity, in one case equivalent to naloxone. This compound (3e) is selective for phenazocine in its antagonist action.

Novel inhibitors of potassium ion channels on human T lymphocytes.

The in vitro biological characterization of a series of 4-(alkylamino)-1,4-dihydroquinolines is reported. These compounds are novel inhibitors of voltage-activated n-type potassium ion (K+) channels in human T lymphocytes. This series, identified from random screening, was found to inhibit [125I]charybdotoxin binding to n-type K+ channels with IC50 values ranging from 10(-6) to 10(-8) M. These analogs also inhibit whole cell n-type K+ currents with IC50 values from 10(-5) to 10(-7) M. The preparation of a series of new 4-(alkylamino)-1,4-dihydroquinolines is described. Structure-activity relationships are discussed. Naphthyl analog 7c, the best compound prepared, exhibited > 100-fold selectivity for inhibition of [125I]charybdotoxin binding to n-type K+ channels compared with inhibition of [3H]dofetilide binding to cardiac K+ channels. These compounds represent a potent and selective series of n-type K+ channel inhibitors that have the potential for further development as anti-inflammatory agents.

Novel inhibitors of the nuclear factor of activated T cells (NFAT)-mediated transcription of beta-galactosidase: potential immunosuppressive and antiinflammatory agents.

The preparation of a series of quinazoline-2,4-diones, 1-3, and pyrrolo[3,4-d]pyrimidine-2,4-diones, 4-8 is described. A small number of quinazolinedione analogs were identified from random screening to possess low micromolar (1.3-4.4 microM) potency in the nuclear factor of activated T cells-1-regulated beta-galactosidase expression assay. An expanded analog search resulted in identifying pyrrolopyrimidinedione 4b which is 5-10-fold (0.26 microM) more potent than the quinazolinediones. Replacement of the benzyl group with naphthyl led to greater potency and conformationally restricted analogs 4u-w. The naphthyl and acenaphthyl analogs are 10-100 times more potent inhibitors of beta-galactosidase expression than 4b. Binding affinity data for displacement of radiolabeled 4s from Jurkat cell membranes reflected an excellent correlation with the IC50 value for inhibition of beta-galactosidase activity. These products, whose structure-activity relationships are discussed, are of interest as potential agents for preventing interleukin-2 gene transcription.

Keto/enol epoxy steroids as HIV-1 Tat inhibitors: structure-activity relationships and pharmacophore localization.

Inhibition of the HIV-1 nuclear regulatory protein tat could potentially yield particularly useful drugs because it functions as an activator of transcription. It has no known cellular counterpart, and deletions in the tat gene destroy the ability of HIV-1 to replicate. We recently reported that a structurally unique class of tat inhibitors, 3-keto/enol 4,5-alpha-epoxy steroids bearing electron-withdrawing substituents at position 2, specifically inhibit tat-induced gene expression in virus free transfected SW480 cells. In this paper, we report on additional SAR (structure-activity relationships) for the steroid series and the localization of the pharmacophore to the A-ring functionality. There is a weak enantioselective preference for the natural steroid stereochemistry and hints of additional SAR in the electron-withdrawing group. Compound 34a is of particular interest in that it inhibits HIV replication in H9 cells at a concentration equivalent to its inhibitory level in the primary tat assay.

In vitro characterization of a novel series of platelet-derived growth factor receptor tyrosine kinase inhibitors.

In this report, we describe the discovery and characterization of a novel biarylhydrazone series of platelet-derived growth factor (PDGF) receptor tyrosine kinase inhibitors typified by the prototype WIN 41662 (3-phenyl-N1-[1-(4-pytidyl)pyrimidine]hydrazone). WIN 41662 inhibited PDGF-stimulated autophosphorylation of PDGF receptors from human vascular smooth muscle cells (hVSMC) with an IC50 value of 60 nM. The inhibitor appeared to be competitive with respect to substrate (Mn(2+)-ATP), having a calculated Ki of 15 +/- 5 nM. WIN 41662 was approximately 500-fold more potent in inhibiting the PDGF receptor tyrosine kinase than the p56lck tyrosine kinase. It was inactive against other serine/threonine and tyrosine kinases tested. WIN 41662 produced concentration-dependent inhibition of PDGF-stimulated receptor autophosphorylation in intact hVSMC with an IC50 < 100 nM. Intracellular Ca2+ mobilization and cell proliferation were events that occurred in hVSMC subsequent to PDGF receptor activation. WIN 41662 inhibited PDGF-stimulated Ca2+ mobilization and cell proliferation ([3H]TdR incorporation) with IC50 values of 430 nM and 2.3 microM, respectively. These effects appeared to be specifically related to PDGF receptor tyrosine kinase inhibition since WIN 41662 was not cytotoxic (in vitro) and since WIN 72039, a close structural analog that does not inhibit PDGF receptor tyrosine kinase, also did not inhibit PDGF-stimulated receptor autophosphorylation, Ca2+ mobilization, or hVSMC proliferation. Thus, WIN 41662 is representative of a novel class of selective PDGF receptor tyrosine kinase inhibitors that inhibit PDGF-regulated secondary events in intact cells.

Pharmacological profiles of tonazocine (Win 42156) and zenazocine (Win 42964).

The effects of tonazocine and zenazocine, two mixed agonist/antagonist analgesics, have been evaluated in a range of antinociceptive assays and in isolated tissue preparations in vitro. Both tonazocine and zenazocine were antinociceptive in writhing tests and in the i.a. bradykinin test, and were antagonists in the rat tail flick test. Additionally, zenazocine demonstrated some antinociceptive activity in the rat tail flick test. In vitro, both tonazocine and zenazocine demonstrated agonist and antagonist properties at mu receptors in the GPI and agonist properties at delta receptors in the MVD. In general, the agonist properties of zenazocine were more marked than those of tonazocine, and the antagonist properties of tonazocine were more marked than those of zenazocine.

Effect of Win 44441-3 and naloxone on endotoxin-induced hypotensive shock in anesthetized hypertensive rats.

A model of endotoxin-induced shock was developed in anesthetized spontaneously hypertensive rats. E. coli lipopolysaccharide (13 mg/kg i.v.) reduced systolic and diastolic blood pressure by at least 51 mm Hg in 80-90% of rats. Naloxone (1.25-10.0 mg/kg i.v.) partially restored blood pressure of hypotensive rats for 6-15 minutes after injection. Win 44441-3 (0.25-2.0 mg/kg i.v.) raised blood pressure for 3-12 minutes after injection. Ten minute pretreatment with naloxone (10 mg/kg i.v.) or Win 44441-3 (0.5 mg/kg i.v.) did not appreciably reduce the hypotensive effect of E. coli lipopolysaccharide. This model is a rapid and convenient bioassay for evaluating the effects of opioid antagonists in endotoxin shock. In this model naloxone and Win 44441-3 exhibited beneficial effects but a prolonged duration of action of the Win compound over naloxone was not observed.

Multiple opioid receptor profile in vitro and activity in vivo of the potent opioid antagonist Win 44,441-3.

Win 44,441-3 is a pure opioid antagonist in rodents in vivo and in isolated tissue preparations in vitro. Win 44,441-3 produced a weak inhibition of electrically-stimulated twitch contractions of the mouse vas deferens (MVD) and guinea-pig ileum (GPI) preparations that was not prevented by naloxone, suggesting that these effects were not mediated through opioid receptors. Similarly, Win 44,441-3 produced a weak, but nonstereoselective antiwrithing effect in the ACh-induced writhing assay. Win 44,441-3 produced a concentration-related antagonism of mu, kappa and delta agonist actions in the MVD and GPI, and was about 10 times more potent than naloxone at each receptor. Also Win 44,441-3 dissociated from mu, kappa and delta receptors more slowly than naloxone. In vivo, Win 44,441-3 produced a dose-related antagonism of morphine and phenazocine-induced antinociception in the tail flick test, and was equipotent with naloxone following s.c. administration. Win 44,441-3 was active orally and demonstrated a significantly longer duration of action than a pharmacologically equivalent oral dose of naloxone vs morphine and phenzaocine in the tail flick test. It can be concluded that Win 44,441-3 is a pure opioid antagonist, 10 times more potent than, with a receptor selectivity profile similar to, that of naloxone in vitro and is of similar potency to, but of longer duration than, naloxone in vivo.

Design and synthesis of a beta-strand inducer. Application to ICAM-1/LFA-1 mediated cellular adhesion.

The binding of lymphocyte function associated antigen (LFA-1) to intercellular adhesion molecule (ICAM-1) is responsible for several types of cellular adhesion. Amino-acid substitution mutants of ICAM-1 have established the importance of several sequences in this protein. We selected the binding region of Glu34 for further study. One published model of domain 1 placed Glu34 near the end of a beta-strand. We designed and synthesized three tripeptide derivatives centered on the Glu34 sequence and attached a platform which, through hydrogen bonds, induces a rigid beta-strand conformation. Variable temperature NMR methods coupled with NOESY 2D NMR data enabled determination of the solution conformation of these compounds.

Damnacanthal is a highly potent, selective inhibitor of p56lck tyrosine kinase activity.

Damnacanthal, an anthraquinone isolated from a plant extract, was found to be a potent, selective inhibitor of p56lck tyrosine kinase activity. The structure, potency, and selectivity of damnacanthal were confirmed by independent synthesis and testing. Damnacanthal exhibited an IC50 of 17 nM for inhibition of p56lck autophosphorylation and an IC50 of 620 nM for phosphorylation of an exogenous peptide by p56lck. Damnacanthal had > 100-fold selectivity for p56lck over the serine/threonine kinases, protein kinase A and protein kinase C, and > 40-fold selectivity for p56lck over four receptor tyrosine kinases. It also demonstrated modest (7-20-fold), but highly statistically significant, selectivity for p56lck over the homologous enzymes p60src and p59fyn. Mechanistic studies demonstrated that damnacanthal was competitive with the peptide binding site, but mixed noncompetitive with the ATP site. Although damnacanthal contains a potentially reactive aldehyde moiety, equilibrium dialysis experiments demonstrated that significant amine formation between damnacanthal and amines occurred only at high concentrations of reactants. However, damnacanthal appeared to bind nonspecifically to membrane lipids and was not active in whole cell tyrosine kinase assays. Damnacanthal is the most potent, selective inhibitor of p56lck tyrosine kinase activity described to date and may represent the starting point for the identification of novel, selective inhibitors of p56lck which are active in whole cell as well as in cell-free systems.