Biochemical synthesis, purification and preliminary pharmacological evaluation of normorphine-3-glucuronide

Normorphine was synthesised from morphine by thermal decomposition of an N-alpha-chloroethylchloroformate adduct, and purified (> 98% purity) using semipreparative HPLC with ultraviolet detection. Normorphine-3-glucuronide (NM3G) was biochemically synthesised using the substrate normorphine, uridine diphosphoglucuronic acid and Sprague-Dawley rat liver microsomes in a 75% yield (relative to normorphine base). The synthesised NM3G was purified by precipitation and washing with acetonitrile. Determinations of purity using HPLC with electrochemical and ultraviolet detection confirmed that the NM3G produced was of high (> 99%) purity. Mass spectrometry, fourier transform infrared spectrophotometry and nuclear magnetic resonance spectrometry confirmed the structure, especially placement of the glucuronide moiety at the 3-phenolic position and not at the 17-nitrogen. Administration of NM3G by the intracerebroventricular (icy) route to rats in doses of 2.5 and 7.5 mu g resulted in the development of central nervous system (CNS) excitatory behavioural effects including myoclonus, chewing, wet-dog shakes, ataxia and explosive motor behaviour. At an icy dose of 7.5 mu g, NM3G also induced short periods of tonic-clonic convulsive activity. Thus, NM3G elicits CNS excitation following supraspinal administration in a manner analogous to morphine-3-glucuronide (M3G), the major metabolite of morphine (1). Further studies are required to determine whether NM3G attenuates morphine-induced antinociception in se similar manner to M3G.

Effect of milling conditions on the synthesis of chromium carbides by mechanical alloying

The synthesis of chromium carbides, Cr7C3 and Cr3C2, by mechanically allowing chromium and carbon powders has been investigated. Milling conditions were found to have a strong influence on the evolution of microstructure, with high collision energies being required to form carbide phases. Milling at intermediate energy levels resulted in the formation of an amorphous phase, and with low energy conditions only grain size refinement of Cr occurred with no evidence of any reaction between Cr and C. The amorphous phase was found to be the precursor to carbide formation. (C) 1997 Elsevier Science S.A.

Synthesis, identification, characterization, stability, solubility, and protein binding of ester derivatives of salicylic acid and diflunisal

O-Acyl esters were prepared from salicylic acid and diflunisal by esterification with the appropriate acyl anhydride (in the presence of sulfuric acid at 80 degrees C) or acyl chloride (in the presence of pyridine at 0 degrees C). Synthesis, identification and characterization of these compounds is described. In vitro hydrolysis, solubility and protein binding studies of these O-acyl esters were performed. For the diflunisal esters, the melting points fell as the side chain was increased from ethyl to pentyl. The melting points showed no significant difference as the length of the side chain was increased from pentyl to heptyl. The aspirin analogues showed a similar trend, The relationship between solubility and carbon chain length agreed closely with that for the melting points with carbon chain length. In vitro non-enzymatic hydrolysis studies concluded that: (1) hydrolysis rate constants generally decreased with carbon chain length; (2) the diflunisal esters have shorter half lives compared with their salicylate counterparts; and (3) the in vitro hydrolysis of these compounds was retarded by the presence of bovine serum albumin. Protein binding experiments showed that the strength of binding of the aspirin and diflunisal analogues to bovine serum albumin increased with carbon chain length. (C) 1997 Elsevier Science B.V.

Chemistry of 5-oxodihydroisoxazoles .18. Synthesis of oxazoles by the photolysis and pyrolysis of 2-acyl-5-oxo-2,5-dihydroisoxazoles

N-Acylisoxazol-5-ones lose carbon dioxide under photochemical and thermal conditions affording iminocarbenes which undergo intramolecular cyclisation through the oxygen of the acyl group to give oxazoles. Under photochemical conditions those acylisoxazolones with electron withdrawing groups at C-4 usually give high yields of oxazoles, while those with electron donating groups at C-4 give only poor yields: the reverse is observed under thermal conditions.

The chemistry of 5-oxodihydroisoxazoles .19. The synthesis and photolysis of N-thioacylisoxazol-5(2H)-ones

5-Oxodihydroisoxazoles react with thiocarbonyl chlorides to afford N-thioacylisoxazol-5(2H)-ones which lose carbon dioxide under photochemical conditions and undergo intramolecular cyclisation of the iminocarbene to afford thiazoles, However, in some cases loss of carbon dioxide is accompanied by loss of sulfur, giving 1,3-oxazin-6-ones.

Potential GABAB receptor antagonists .9. The synthesis of 3-amino-3-(4-chlorophenyl)propanoic acid, 2-amino-2-(4-chlorophenyl)ethylphosphonic acid and 2-amino-2-(4-chlorophenyl)ethanesulfonic acid

This paper describes the synthesis of 3-amino-3-(4-chlorophenyl)propanoic acid and the corresponding phosphonic and sulfonic acids, lower homologues of baclofen, phaclofen and saclofen respectively. The chlorinated acids were all weak specific antagonists of GABA at the GABAB receptor, with the sulfonic acid (pA(2) 4.0) being stronger than the phosphonic acid (pA(2) 3.8) and carboxylic acid (pA(2) 3.5).

The biomimetic synthesis of marine epoxylipids: Bisepoxides to tetrahydrofurans

The biomimetic synthesis of novel lipids 1, 2, 8 and 10 obtained from the southern Australian marine brown alga Notheia anomala has been achieved, and features the acid mediated conversion of methylene interrupted bisepoxides to tetrahydrofurans. (C) 1997 Elsevier Science Ltd.

Effect of lipopolysaccharide from periodontal pathogens on the production of tissue plasminogen activator and plasminogen activator inhibitor 2 by human gingival fibroblasts

Both tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 2 (PAI-2) are important proteolysis factors present in inflamed human periodontal tissues. The aim of the present study was to investigate the effect of lipopolysaccharide (LPS) on the synthesis: of t-PA and PAI-2 by human gingival fibroblasts (HGF). LPS from different periodontal pathogens including Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum were extracted by the hot phenol water method. The levels of t-PA and PAI-2 secreted into the cell culture media were measured by enzyme-linked immunosorbent assays (ELISA). The mRNA for t-PA and PAI-2 were measured by RT-PCR. The results showed t-PA synthesis was increased in response to all types of LPS studied and PAI-2 level was increased by LPS from A. actinomycetemcomitans and F. nucleatum, but not P. gingivalis. When comparing the effects of LPS from non-periodontal bacteria (Escherichia coli and Salmonella enteritidis) with the LPS from periodontal pathogens, we found that the ratio of t-PA to PAI-2 was greater following exposure of the cells to LPS from periodontal pathogens. The highest ratio of t-PA to PAI-2 was found in those cells exposed to LPS from P. gingivalis. These results indicate that LPS derived from periodontal pathogens may cause unbalanced regulation of plasminogen activator and plasminogen activator inhibitor by HGF and such an effect may, in part, contribute to the destruction of periodontal connective tissue through dysregulated pericellular proteolysis.

Identification and total synthesis of novel fatty acids from the siphonarid limpet Siphonaria denticulata

The novel fatty acids 17-methyl-6(Z)-octadecenoic acid and 17-methyl-7(Z)-octadecenoic acid were identified for the first time in nature in the mollusk Siphonaria denticulata from Queensland, Australia. The principal fatty acids in the limpet were hexadecanoic acid, octadecanoic acid, and (Z)-9-octadecenoic acid, while the most interesting series of monounsaturated fatty acids was a family of five nonadecenoic acids with double bonds at either Delta (7), Delta (9), Delta (11), Delta (12), or Delta (13). The novel compounds were characterized using a combination of GC-MS and chemical transformations, such as dimethyl disulfide derivatization. The first total syntheses for the two novel methyl-branched nonadecenoic acids are also described, and these were accomplished in four to five steps and in high yields.

Lipophilic methotrexate conjugates with glucose-lipoamino acid moieties: Synthesis and in vitro antitumor activity

To obtain methotrexate (MTX) derivatives with a balanced hydrolipophilic character, we synthesized a series of conjugates in which the drug was linked to lipoamino acid (LAA)-glucose residues (LAAG-MTX). These conjugates displayed increased solubility in polar media compared with the corresponding LAA-MTX conjugates previously described. In vitro biological testing of LAAG-MTX indicated that the introduction of the sugar moiety decreased the biological activity of these MTX conjugates. The tetradecyl derivative 6b, however, was effective in inhibiting the dihydrofolate reductase activity in vitro and showed an inhibitory effect on human lymphoblastoid cell growth. (C) 2001 Wiley-Liss, Inc.