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A 14-step biomimetic synthetic route to glyceollin I (1.5% overall yield) was developed and deployed to produce the natural enantiomeric form in soy, its unnatural stereoisomer, and a racemic mixture. Enantiomeric excess was assessed by asymmetric NMR shift reagents and chiral HPLC. Antiproliferative effects were measured in human breast, ovarian, and prostate cancer cell lines, with all three chiral forms exhibiting growth inhibition (GI) in the low to mid μM range for all cells. The natural enantiomer, and in some cases the racemate, gave significantly greater GI than the unnatural stereoisomer for estrogen receptor positive (ER+) versus ER–breast/ovarian cell lines as well as for androgen receptor positive (AR+) versus AR–prostate cancer cells. Surprisingly, differences between ER+and ER–cell lines were not altered by media estrogen conditions. These results suggest the antiproliferative mechanism of glyceollin I stereoisomers may be more complicated than strictly ER interactions.

The rise in organisms resistant to existing drugs has added urgency to the search for new antimicrobial agents. Aspartate β-semialdehyde dehydrogenase (ASADH) catalyzes a critical step in an essential microbial pathway that is absent in mammals. Our laboratory is using fragment library screening to identify efficient and selective ASADH inhibitors. These preliminary agents are then tested to identify compounds with desired antimicrobial properties for further refinement. Toward this end, we have established a microplate-based, dual-assay approach using a single reagent to evaluate antibiotic activity and mammalian cell toxicity during early stage development. The bacterial assay uses nonpathogenic bacteria to allow efficacy testing without a dedicated microbial laboratory. Toxicity assays are performed with a panel of mammalian cells derived from representative susceptible tissues. These assays can be adapted to target other microbial systems, such as fungi and biofilms, and additional mammalian cell lines can be added as needed. Application of this screening approach to antibiotic standards demonstrates the ability of these assays to identify bacterial selectivity and potential toxicity issues. Tests with selected agents from the ASADH inhibitor fragment library show some compounds with antibiotic activity, but as expected, most of these early agents display higher than desired mammalian cell toxicity.

Total syntheses of racemic and (−)-glycinol (1) are described. A Wittig reaction produced the isoflav-3-ene from which a Sharpless dihydroxylation introduced either the racemic or enantiomeric 6a-hydroxy group. A 5.5% overall yield of racemic material was obtained after 12 steps. A method was devised for a one-pot switch of protecting groups masking a sensitive resorcinolic para-functionality, and conditions were optimized to prompt spontaneous closure of the pterocarpanolic dihydrofuran upon subsequent exposure of its ortho-functionality. These improvements eliminated two steps and increased the overall yield to 9.8% during production of the natural enantiomer.

Peptidylglycine α-amidating monooxygenase (PAM) converts inactive terminal-glycine prohormones into their activated α-amidated forms. PAM is thought to play a role in the development of antiandrogen drug resistance in prostate cancer (CaP) through PAM-activated autocrine growth. On the basis of the previous finding that many lung cancer cell lines excrete PAM into their culture media, this study investigates PAM levels in media collected from human CaP cell line cultures. Androgen-independent DU145 and PC-3 prostate cancer cell lines exhibited readily detectable levels of PAM activity in extracts and media, whereas the androgen-dependent LNCaP cell line showed little or no activity. Because of the much larger volume of media versus cell extracts, more than 90% of the total PAM activity was located in the media for both the PC-3 and DU145 cell lines, providing a readily accessible source of CaP PAM. A simple, scalable method to obtain PAM from the culture media of androgen-independent human prostate cancer cell lines is described in this article. This approach provides a much easier means of collecting CaP-derived PAM than previously described cell fractionation procedures and should facilitate the investigations of the role and targeting of PAM in hormone-independent CaP.

A microplate screening method has been developed to evaluate the effects of test agents on the accumulation of the fluorescent P-glycoprotein (Pgp) substrates Hoechst 33342, rhodamine 123, and rhodamine 6G in multidrug-resistant (MDR) breast cancer cells that overexpress Pgp. All three substrates exhibit substantially higher accumulation in MCF7 non-MDR cells versus NCI/ADR-RES MDR cells, while incubation with 50 μM reserpine significantly reduces or eliminates these differences. Rhodamine 123 shows the lowest substrate accumulation efficiency in non-MDR cells relative to the substrate incubation level. The effects of several chemosensitizing agents and a series of paclitaxel analogs on the accumulation of each fluorescent substrate suggest that there are distinct differences in the substrate interaction profiles exhibited by these different agents. The described methods may be useful in Pgp-related research in the areas of cancer MDR, oral drug absorption, the blood-brain barrier, renal/hepatic transport processes, and drug-drug interactions.

The future of medicinal chemistry as both a pure and an applied science has been considered relative to trends that are already having a significant impact upon drug discovery and development. After quickly reviewing how medicinal chemistry has been practiced to date, topics considered into the future include: pursuing therapeutic efficacy, addressing 3D structure within database settings, assuring absorption, directing distribution, controlling metabolism, optimizing elimination, and avoiding toxicity. It is suggested that as the exploration of these topics proceeds into the new millennium by deploying combinatorial chemistry coupled to high-throughput screening, medicinal chemistry will play a key role as a central interpreter of the underlying structure­activity relationships such that the overall process of drug discovery and development will be knowledge-generating. As fundamental knowledge accumulates across all of these areas, virtual approaches will eventually become firmly anchored to experimental and theoretical databases having validated clinical predictability. The potential impact of some of the recent trends in process chemistry, and in analytical chemistry using X-ray diffraction as an exemplary method, are additionally highlighted before reiterating the article's major points in a summary section. From this purview, the summary also considers the education of future medicinal chemists, notes potential issues related to the future of pharmaceutical-related intellectual property, and concludes by alluding to a brewing paradox between enhanced knowledge and enhanced molecular diversity relative to the future discovery of new drugs.

Dilute solutions of paclitaxel-related derivatives having chloroacetyl esters in the C2′ position undergo ready methanolysis according to pseudo first-order kinetics while more concentrated solutions appear to be stabilized, possibly by the formation of hydrophobic aggregates that tend to bury this reaction center. Methanolysis is also attenuated in the presence of weak acid, suggesting that paclitaxel's neighboring benzamide nitrogen may be participating in the reaction by serving as an assisting nucleophile.

A benzoyl migration has been used to remove two steps during the asymmetric dihydroxylation literature route to (2R,3S)-N-benzoyl-3-phenylisoserine, the C-13 position side chain of paclitaxel. The modification provides the product as its more desirable methyl ester in similar overall yields with no loss of enantiomeric purity when scaled up to multigram quantities.

Homogenates of human pituitaries were centrifuged at 30 000 × gand the supernatant chromatographed on Sephadex G-100. Approximately 1 % of the radioimmunologically measured total activity of TSH was eluted in the void volume. Rechromatography of this material on Sephadex G-200 usually showed TSH-activity at Kav= 0.5 (regular TSH), Kav= 0 (void volume-TSH) and at Kav= 0.3 ("big"-TSH). "Big"-TSH was extracted from the corresponding fractions by affinity-chromatography with solid phase anti-TSH. It was eluted with 5 mol/l ammonium thiocyanate and further characterized:1. The molecular weight was approximately 200 000 by comparison with bovine catalase on Sephadex G-200.2. Immunoidentity as compared with standard-TSH (M. R. C. 68/38) was shown by parallel dilution curves in the radioimmunoassay.3. Concanavalin-A-Sepharose adsorbed "big"-TSH, which could be eluted with α-methyl-D-mannoside, indicating the glycoprotein nature of "big"-TSH.4. On polyacrylamide-gel-electrophoresis pH 7.5, "big"-TSH migrated faster (RF= 0.32) than regular TSH (RF= 0.1), indicating a more negatively charged molecule.5. "Big"-TSH, in contrast to regular TSH, was remarkably stable against 6 mol/l guanidine hydrochloride, suggesting a covalently linked (aggregate) structure.6. 1 % mercaptoethanol destroyed the immunological activity of both regular and "big"-TSH.7. "Big"-TSH was digested by trypsin, under mild conditions, to radioimmunologically active products with molecular weights between "big"- and regular TSH, but practically no regular TSH was formed.8. "Big"-TSH and guanidine-treated "big"-TSH, as well as regular TSH and TSH from the void volume of Sephadex G-200 columns, exhibited biological activity in a cytochemical bioassay in good agreement with the respective immunological activities.

Seven pairs of monoquaternary enantiomeric neuromuscular junction blocking agents were prepared in which the carbon asymmetry is adjacent to the quaternized nitrogen moiety. The tertiary amines from which the blocking species were obtained are carnegine, laudanosine, N‐methylpavine, corydine, isocorydine, glaucine, and boldine. Curarimimetic potencies, obtained with an in vivocat tongue‐hypoglossal nerve preparation, were obtained for the enantiomeric methiodides of each of these amines. Possible contributions to activity by preferential binding to blood components or by selective inhibition of acetylcholinesterase also were studied. The combined studies indicate that there is a modest preference by the neuromuscular junction of the cat for monoquaternary blockers with the (S)‐configuration.

Based on the pharmacophoric relationship heterocycle-phenyl-imidazole (H-P-I) and upon consideration of several potent inhibitors of cardiac cAMP phosphodiesterase, a topographical model of this receptor is proposed. The model consists of two binding sites which interact with H, two steric features, preferential rotation of P away from coplanarity with H, and a binding site for an electron-rich system (I). It is supported by molecular modeling studies and accommodates a variety of inhibitors. It also encompasses the active site of the enzyme and can distinguish cAMP from cGMP as substrates.

Amphetamine and certain of its methoxylated derivatives show a high degree of interaction with NMR shift reagents of the type tris(1,1,1,2,2,3,3‐heptafluoro‐7,7‐dimethyl‐4,6‐octanedione)europium(III). The shifts are not accompanied by appreciable line broadening, and both the aliphatic and aromatic protons can be resolved. The strong interaction between amine and shift reagent diminishes rapidly as the amine function is alkylated. For derivatives containing ortho‐methoxyl groups, a weaker interaction with this functionality also becomes evident as the amine is alkylated. The stereospecificity of the shifting process was investigated by employing tris[3‐(trifluoroacetyl)‐d‐camphorato]europium(III), a chiral shift reagent, with stereochemically pure enantiomers and known enantiomeric mixtures. Although certain (R)‐enantiomers showed greater downfield C‐methyl group shifts, these shift differences from the corresponding (S)‐enantiomers were small and not well resolved.

We synthesized a directed library of compounds to explore the structure–activity relationships of peroxisome proliferator-activated receptor δ (PPARδ) activation relative to mesenchymal stem cell (MSC) osteogenesis. Our scaffold used para-substituted cinnamic acids as a polar headgroup, a heteroatom and heterocycle core connecting units, and substituted phenyl groups for the lipophilic tail. Compounds were screened for their ability to increase osteogenesis in MSCs, and the most promising were examined for subunit specificity using a quantitative PPAR transactivation assay. Six compounds were selected for in vivo studies in an ovariectomized mouse model of human postmenopausal osteoporosis. Four compounds improved bone density in vivo, with two (12dand 31a) having activity comparable to that of GW0742, a well-studied PPARδ-selective agonist. 31a(2-methyl-4-[N-methyl-N-[5-methylene-4-methyl-2-[4-(trifluoromethyl)phenyl]thiazole]]aminocinnamic acid) had the highest selectivity for PPARδ compared to other subtypes, its selectivity far exceeding that of GW0742. Our results confirm that PPARδ is a new drug target for possible treatment of osteoporosis via in situ manipulation of MSCs.

Two enantiomeric pairs of neuromuscular junction blocking agents were prepared in which an asymmetric carbon atom is adjacent to an asymmetric quaternized nitrogen moiety. The blocking agents were obtained from the enantiomers of laudanosine by stereoselective quaternization with benzyl and ethyl iodides. Curarimimetic potencies were measured with an in vivocat hypoglossal nerve-tongue muscle preparation. The studies suggest that the asymmetry present in these structures does not lead to significant differences in blocking potency between enantiomers.

Based on review and examination of recent additions to dopaminergic structure-activity relationships, a topographical model of the renal vascular dopamine receptor is presented. The implications of this model for the design of new dopaminergic drug candidates are discussed briefly.

An extraction and GLC assay procedure was developed for quantitation of procainamide hydrochloride and acecainide hydrochloride in rat feed. 4-Amino-N-[2-(dipropylamino)ethyl]benzamide hydrochloride was synthesized and utilized as an internal standard. The assay has good precision and accuracy and was used to establish the stability of acecainide hydrochloride and procainamide hydrochloride in rat feed.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.