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PubMed2006

Synthetic studies toward highly functionalized 5beta-lanosterol derivatives: a versatile approach utilizing anionic cycloaddition.

Stereoselective synthesis of the potentially biologically valuable 5beta-lanosteroidal-type backbone was achieved via anionic cycloaddition. Synthesis of the two new bicyclic Nazarov intermediates 14 and 40 and their cycloaddition with chiral cyclohexenone 25 and further functional group manipulations resulted in highly functionalized tetracyclic intermediates 28 and 44. These synthetic intermediates could lead to the total synthesis of new lanosterol-based inhibitors.

Amination↗
PubMed1995

New azacyclopropene derivatives from Dysidea fragilis collected in Pohnpei.

The sponge Dysidea fragilis from Pohnpei contained four azacyclopropene derivatives, (4E)-S-dysidazirine [2], which is the optical enantiomer of the known compound dysidazirine [1], (4Z)-dysidazirine [3], (4E)-S-antazirine [4], and (4Z)-antazirine [5]. The structures of the new compounds were elucidated by interpretation of spectral data.

Animals↗
PubMed1996

Insecticidal quinazoline derivatives with (trifluoromethyl)diazirinyl and azido substituents as NADH:ubiquinone oxidoreductase inhibitors and candidate photoaffinity probes.

Two candidate photoaffinity probes are designed from 4-substituted quinazolines known to be potent insecticides/acaricides and NADH:ubiquinone oxidoreductase inhibitors acting at or near the rotenone site. 4-(11-Azidoundecyl-2-amino)quinazoline, based on the undecylamino analog SAN 548A as a prototype, was synthesized in 18% overall yield from ethyl 10-undecenoate by oxidation of the terminal double bond, reductive amination, coupling to 4-chloroquinazoline, and functional group manipulation of the terminal ethyl ester to an alcohol, a mesylate and finally nucleophilic displacement with azide ions. 4-(4-(3-(Trifluoromethyl)-3H-diazirin-3-yl)phenethoxy)quinaz oline [the (trifluoromethyl)diazirinyl analog of fenazaquin insecticide/acaricide] was prepared from 4-bromophenethyl alcohol in 31% overall yield by first introducing the trifluoromethylketone moiety followed by its conversion to the (trifluoromethyl)-diazirine and finally coupling to 4-chloroquinazoline as above. Both candidate photoaffinity probes have the inhibitory potency of rotenone (IC50 of 3-4 nM in each case). The azidoundecylamino compound has inadequate photoreactivity whereas that of the (trifluoromethyl)diazirinyl analog is ideal at 350 nm. Radiosynthesis of the latter photoaffinity ligand included introduction of the diazirinyl moiety as the carbene precursor, oxidation of (trifluoromethyl)diazirinylphenethyl alcohol to the corresponding acid with Jones' reagent, and reduction of the phenacetyl chloride intermediate with sodium borotritide to incorporate tritium.

Affinity Labels↗
PubMedDate not supplied

[Synthesis of nucleotide derivatives containing 1-(4-(3-(trifluoromethyl)-3H-diazirin-3-yl)benzamido)-2,3-propanediol for photoaffinity modification of proteins and nucleic acid].

1-(4-(3-(Trifluoromethyl)-3H-diazirin-3-yl)benzamido)-3-O-(4,4'- dimethoxytrityl)-2,3-propanediol phosphoramidite was synthesized and used as a modified unit in the automatic synthesis of oligodeoxyribonucleotides. Pentadecathymidylates with various numbers of 2,3-propanediol moieties substituted with aryl(trifluoromethyl)diazirinyl (ATFMD) were obtained, and the thermal stability of their duplexes with (dA)15 were studied. One ATFMD-propanediol residue was shown to reduce the thermal stability of the duplex by 8-9 degrees C. The irradiation of the ATFMD-containing duplexes by UV light with the wavelength of 350 nm was found to cause the cross-linking reaction of the ATFMD-containing strand with the complementary strand and the formation of the cross-linked duplexes. The photomodification efficiency was independent of the oligonucleotide sequence, with each ATFMD group providing for 5% cross-linking. The irradiation of an ATFMD-containing duplex, a substrate of the HIV-1 integrase, in the presence of this enzyme resulted in the covalent DNA-protein complex. The oligonucleotides with the 1-(4-(3-(trifluoromethyl)-3H-diazirin-3-yl)benzamido)-2,3-propanediol moiety in their chains can be used for the photoaffinity modification of both nucleic acids and proteins that recognize them. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2002, vol. 28, no. 4; see also http://www.maik.ru.

Azirines↗
PubMed1971

Early reactions of the subcutaneous tissue to repeated injections of carcinogens in aqueous solutions.

Four water-soluble carcinogens were injected at the same site subcutaneously into rats, mice or guinea-pigs, twice weekly for 5-8 weeks in order to study the evolution of the early tissue reaction. MNU was injected into rats as 0·1 ml. of 0·5% solution, and into mice as 0·1 ml. of 0·05% solution. NQO was administered to rats (0·1 or 0·2 ml. of 0·25 or 0·1%) mice (0·1 of 0·05%) and guinea-pigs (0·5 of 0·1%). Propane sultone and BEI were administered to rats only, the former as 0·1 ml. of 3% and the latter as 0·5 ml. of 2·0% solution.The principal features of the tissue reaction produced by each of the four compounds in rats were similar and consisted of destruction of subcutaneous tissue, deposition of fibrin and "fibrinoid", an abnormal pattern of fibroblastic proliferation with cytomegaly of some fibroblasts and deposition of mucopolysaccharide but little collagen formation. Moreover, the appearance of fibroblastic proliferation was delayed from the normal 2-5 days to 14-16 days.These features are consistent with the known early effects of carcinogens on proliferating target tissues, and differ considerably from those found in the early reactive lesions to repeated injection of solutions of substances possessing physical properties such as surface activity or hypertonicity, or which precipitate at the injection site.

Adipose Tissue↗
PubMed1971

The sensitivity to chemotherapeutic agents of a rat tumour grown in immunosuppressed mice.

The rat Walker 256 tumour was grown in mice that had previously been thymectomized and treated with anti-lymphocyte serum. These rat tumour-bearing mice were used to determine the therapeutic indices of 4 anti-tumour drugs.The agent with the highest index of the four examined was 5-aziridino 2,4-dinitrobenzamide (CB1954), followed by melphalan, aniline mustard and methotrexate, in that order. This rank order is the same as that found when therapeutic indices are determined on the Walker tumour growing in the rat. In this system, therefore, drugs have been ranked correctly in effectiveness against a rat tumour by measuring their effects on the tumour when growing in an immunosuppressed xenogeneic species. The implications for testing the drug sensitivity of individual human tumours before treating the patient are discussed.

Animals↗
PubMed1982

Effect of chemotherapy on natural-killer activity and antibody-dependent cell-mediated cytotoxicity in carcinoma of the lung.

The effect of chemotherapy on natural killer (NK) activity and antibody-dependent cell-mediated cytotoxicity (ADCC) in 15 advanced carcinomas of the lung was examined with regard to the drug, dose, route and timing of administration. The relationship between the effect of chemotherapy on the prognosis for the patients, and the changes in NK activity and ADCC, was also analysed. The NK activity and ADCC in patients with poor prognosis were significantly subnormal, even before treatment. The NK activity and ADCC began to decrease 2 weeks after the initiation of treatment and reached the lowest level during the 3rd or 4th week in all patients. Thereafter, they returned to the pretreatment level in 8 patients with stabilized disease. In contrast, they were not restored in 7 patients with progressive disease and poor prognosis. In 4 patients it was found that the effect of chemotherapy with pepleomycin and carbazilquinone on NK activity and ADCC differed according to the drug used. From this pilot study it is suggested that NK activity and ADCC are valuable prognostic factors in patients with advanced carcinoma of the lung, and that detailed analysis of the effect of each anticancer agent on NK activity and ADCC is desirable for the establishment of better treatment regimens for advanced carcinoma of the lung.

Aged↗
PubMed1984

Radiation sensitization and chemopotentiation: RSU 1069, a compound more efficient than misonidazole in vitro and in vivo.

Electron affinity as measured by the one-electron reduction potential, E17, is the major factor influencing radiosensitizing efficiency in vitro. RSU 1069 has an electron affinity (E17 = -398 mV) similar to misonidazole; however, the ability of this compound to sensitize hypoxic cells is considerably greater than that of misonidazole, e.g. 0.2 mM RSU 1069 gives an enhancement ratio of 2.2 compared to 1.5 for the same concentration of misonidazole. Radiosensitization studies with the MT tumour in vivo also showed RSU 1069 to be a more efficient sensitizer than misonidazole. An administered dose of only 0.08 mg g-1 RSU 1069 yielded an enhancement of 1.8 to 1.9 using tumour cell survival and tumour cure as end-points. The ability of RSU 1069 to potentiate the cytotoxic action of melphalan towards the MT tumour was also examined. RSU 1069 (0.08 mg g-1) given to mice 1 h before melphalan resulted in an enhancement of 3.0. In contrast, previous studies had shown with a series of nitroimidazoles including misonidazole that Ro 03-8799 was the most effective potentiating agent, but this only gave an enhancement of 2.3 at a 10-fold higher dose than RSU 1069. RSU 1069 is a compound of substantial promise both as a radiosensitizer and chemopotentiating agent and warrants further investigation.

Animals↗
PubMed1982

Diaziquone, 2,5-diaziridinyl-3,6-biscarboethoxyamino-1,4-benzoquinone, plasma and cerebrospinal fluid kinetics.

Plasma and cerebrospinal fluid (CSF) kinetics of diaziquone, 2,5-diaziridinyl-3,6-biscarboethoxyamino-1,4-benzoquinone (AZQ), were evaluated after intravenous injection in patients with implanted Ommaya reservoirs. After a 30-min infusion plasma disappearance was very rapid, with a disposition half-life of 2 to 6 min and on elimination half-life of 25 to 35 min. Area under the concentration-time curve for CSF was 22% to 42% of the corresponding plasma area. Based upon total plasma AZQ concentration, volume of distribution for AZQ was 2.0 to 10.0 l/m2. Plasma binding of AZQ was 79% in one normal subject. When the effect of plasma binding is considered, distribution volumes are more plausible and it appears that free plasma AZQ is completely available to the CSF.

Adult↗