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Abstract Cyclopentenyl cytosine (CPE-C, 3) possesses excellent antitumor and antiviral activity. The synthesis of the analogous cyclopentenyl triazine nucleoside, 5-aza-CPE-C (4), was accomplished by a novel approach that utilized a key 1-cyclopentenyl-4-methylisobiuret intermediate (7) produced from the corresponding cyclopentenylamine 5. 5-Aza-CPE-C was more than six-hundred times less potent than CPE-C both in its capacity to reduce CTP levels as well as in its antitumor and antiviral activity.

Abstract To assess the structure-activity relationship for antiviral activity, a series of 3′-deoxy-3′-N-functionalized thymidine analogues were synthesized. Several of these thymidine analogues show moderate in vitro activity against HIV-1 and HIV-2.

Several new analogues of the novel anti-HIV agent cosalane have been synthesized and evaluated as inhibitors of HIV-1 integrase and protease, HIV-1 replication, HIV-1 and HIV-2 cytopathicity, HIV-1- and HIV-2-mediated syncytium formation, and cytopathicity of a variety of human pathogenic viruses. The congeners displayed enhanced potencies relative to cosalane itself as inhibitors of HIV-1 integrase and protease. The two most potent analogues against HIV-1 integrase displayed IC50 values of 2.2 microM, while the three most potent compounds against HIV-1 protease had IC50 values in the 0.35-0.39 microM range. In addition to its activity against HIV-1 and HIV-2 cytopathicity, cosalane inhibited the cytopathic effects of herpes simplex virus-1, herpes simplex virus-2, and human cytomegalovirus at concentrations that were well below the cytotoxic concentrations. Potentially useful antiviral activities were also revealed for some of the new cosalane congeners against influenza virus, Junin virus, and Tacaribe virus.

Starting from 3-O-mesyl-1,2-O-isopropylidene-alpha-D-allofuranose (9) the anomeric mixtures of the requisite carbohydrates 1,2-di-O-acetyl-6-O-benzoyl-5-deoxy-3-O-mesyl-D-allofuranoses++ + 17A alpha/beta, 1,2-di-O-acetyl-5,6-di-O-benzoyl-3-O-mesyl-D-allofuranoses 17B alpha/beta, and 1,2-di-O-acetyl-5,6-di-O-benzoyl-3-O-mesyl-L-talofuranoses 17C alpha/beta were synthesized. 1,2-Di-O-acetyl-5-O-benzoyl-6-deoxy-3-O-mesyl-D-allofuranoses++ + 17D alpha/beta and the corresponding L-talofuranoses 17E alpha/beta were obtained from 6-deoxy-3,5-di-O-benzoyl-1,2-O-isopropylidene-alpha-D- allofuranose (12) and the corresponding beta-L-talofuranose 13. Coupling of these sugar derivatives with thymine gave the beta-nucleoside derivatives 18A-E. Treatment of compounds 18A-E with DBU produced the corresponding 2,3'-anhydro nucleosides 19A-E with a free 2'-OH group. After deoxygenation of 2'-O-[[(4-methylphenyl)oxy]thiocarbonyl] compounds 20A-E with tributyltin hydride the 2,3'-anhydro bridge of the 2'-deoxynucleosides 21A-E was opened with LiN3 to produce the protected 3'-azido-2,3'-dideoxynucleoside derivatives 22A-G. Saponification with NaOCH3 gave 1-(3'-azido-2',3',5'-trideoxy-beta-D-allofuranosyl)thymine (2; homo-AZT), the 5'-C-(hydroxymethyl) derivatives of AZT 1-(3'-azido-2',3'- dideoxy-beta-D-allofuranosyl)thymine (3) and 1-(3'-azido-2',3'-dideoxy-alpha-L-talofuranosyl)thymine (4), and the 5'-C-methyl derivatives of AZT 1-(3'-azido-2',3',6'-trideoxy-beta-D-allofuranosyl)thymine (5) and 1-(3'-azido-2',3',6'-trideoxy-alpha-L-talofuranosyl)thymine (6). Compounds 2-6 were evaluated for their inhibitory effect on human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) replication in MT-4 cells and found inactive at subtoxic concentrations. Compounds 2-4 and 6 are not effective against herpes simplex virus type 1 (HSV-1) and type 2 (HIV-2), vaccinia virus (VV), and vesicular stomatitis virus (VSV) at 400 micrograms/mL. 5 is slightly active against HSV-1, HSV-2 and VV at 150, 300, and 300 micrograms/mL, respectively.

A synthetic gene encoding for HIV‐1 integrase was designed to circumvent the intrinsic instability and the repressor elements present in the wild‐type gene. High‐level expression of HIV‐1 integrase was obtained in various human cell lines independently of viral accessory proteins. A human 293T cell line was selected that stably expresses HIV‐1 integrase and has growth kinetics comparable to the parental cell line. The enzyme was localized in the nucleus and remained stably associated with the chromosomes during mitosis. Lentiviral vector particles carrying the inactivating D64V mutation in the integrase gene were capable of stably transducing 293T cells when complemented in the producer cells with integrase expressed from the synthetic gene. When the cell line that stably expresses integrase was infected with the defective viral particles, complementation of integrase activity was detected as well. Expression of active HIV‐1 integrase in human cells will facilitate the study of the interplay between host and viral factors during integration.—Cherepanov, P., Pluymers, W., Claeys, A., Proost, P., De Clercq, E., Debyser, Z. High‐level expression of active HIV‐1 integrase from a synthetic gene in human cells. FASEB J. 14, 1389–1399 (2000)

Traditionally, process planning and scheduling have been rather separate activities within a company. Nowadays, the need for more flexible production and shorter production lead times urges for a close collaboration between these activities as a first step towards simultaneous engineering. This article describes the results of the ESPRIT project COMPLAN, which aims at the implementation of an integrated automatic process planning and scheduling system based on the concept of non-linear process plans. In addition to the use of NLPP for flexible load balancing and reactive rescheduling, a new collaborative approach is presented that is based on production constraints as a means to realize a feedback from scheduling to process planning. A process-planning kernel is described that integrates this concept of production constraints.

(+)- Trans-(5R,6R)-5-bromo-5-ethyl-6-ethoxy-5,6-dihydro-5′-O-valeryl-2′-deoxyuridine (3) and (+)- trans-(5R,6R)-5-bromo-5-ethyl-6-ethoxy-5,6-dihydro-3′,5′-di-O-valery[-2′-deoxyuridine (4) were synthesized in 55% and 8.6% yield, respectively, by esterification of the 5′-hydroxyl group of (+)- trans-(5R,6R)-5-bromo-5-ethyl-6-ethoxy-5,6-dihydro-2′-deoxyuridine (2) using valeryl chloride. [4- 14 C]-3 and [4- 14 C]-4 were synthesized in 79% and 64% chemical and radiochemical yield, respectively, by similar esterifications of [4- 14 C]-2. The double prodrug 3 was readily hydrolysed (> 95% in 8 min) to 5-ethyl-2′-deoxyuridine (EDU) by porcine liver esterase in vitro. The biotransformations of 2 and 3 were studied following i.v. injection of a 0.4 mmol/kg i.v. dose to male Balb/c mice. The single prodrug 2 was rapidly cleared (<10 min) from the blood. The area under the blood concentration-time curve (AUC) for EDU, as a metabolite of 2, was higher (2.1 ± 0.4 μmol.h.g −1 ) than the AUC observed when EDU itself was injected (1.7 ± 0.2 μmol.h.g −1 ). The double prodrug 3 provided a sustained high concentration of EDU in blood, with an AUC for EDU, as a metabolite of 3, of 1.8 ± 0.2 μmol.hr.g −1 . 5′-O-Valeryl-5-ethyl-2′-deoxyuridine and 3 were both detected in blood samples collected up to 35 min post i.v. injection. 5-Ethyluracil and 5-(1-hydroxyethyl)-uracil were identified as secondary metabolites of EDU, 2 and 3. Compared to [4- 14 C]-EDU, i.v. injection of [4- 14 C]-3 or [4- 14 C]-4 provided significantly higher (P < 0.001) radioactivity levels in the brain, but neither EDU, 2 or 3 protected mice against intracerebral herpes simplex virus infection. Hepatic uptakes of 2, 3 and 4, in mice, were similar to each other despite the respective substantial increases in both molecular weight and lipophilicity of this series. In rats, biliary excretion over the 0-4 h period after i.v. injection accounted for only 2.9-3.9% of the injected dose for these prodrugs.

The selective and potent anti-herpesvirus drug, (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVdU), has been examined for its inhibitory effects on several parameters of Epstein-Barr virus (EBV) infection in the lymphoblastoid cell lines Raji, P3HR-1, B-95-8 and P3 hybrid cells (a human embryo oropharyngeal cell line fused with a nasopharyngeal carcinoma cell line). At a dosage of 0.03 to 0.1 mM, BVdU caused a marked inhibition of (i) spontaneous viral capsid antigen (VCA) expression in B-95-8 and P3 hybrid cells, (ii) VCA expression and DNA synthesis in B-95-8 cells induced with croton oil and n-butyrate, (iii) early antigen (EA) expression and DNA synthesis in Raji cells superinfected with EBV, and (iv) VCA expression and DNA synthesis in B-95-8 cells superinfected with EBV. In its inhibitory effects on these various parameters of EBV infection, BVdU appears to be comparable to acyclovir [9-(2-hydroxyethoxymethyl)guanine], another selective anti-herpesvirus drug which has been previously recognized as an effective inhibitor of EBV replication.

The disease burden of liver cancer in China has declined over the past 30 years. However, it remains important to control liver cancer among high-risk populations, especially elderly males with obesity, alcohol use, tobacco use, and/or drug abuse.

Additive manufacturing (AM) techniques are promising manufacturing methods for the production of complex parts in small series. In this work, laser sintering (LS) was used to fabricate reaction bonded silicon carbide (RBSC) parts. First, silicon carbide (SiC) and silicon (Si) powders were mixed in order to obtain a homogeneous powder. This powder mixture was subsequently laser sintered, where the Si melts and re-solidifies to bind the primary SiC particles. Afterwards, these SiSiC preforms were impregnated with a phenolic resin. This phenolic resin was pyrolysed yielding porous carbon, which was transformed into secondary reaction formed SiC when the preforms were infiltrated with molten silicon in the final step. This resulted in fully dense RBSC parts with up to 84 vol% SiC. The optimized SiSiC combined a Vickers hardness of 2045 HV, an electrical conductivity of 5.3 × 103 S/m, a Young's modulus of 285 GPa and a 4-point bending strength of 162 MPa.

The antineoplastic efficacy of P-4055, a 5'-elaidic acid (C18:1, unsaturated fatty acid) ester of cytarabine, a nucleoside antimetabolite frequently used in the treatment of hematological malignancies, was examined in several in vivo models for human cancer. In initial dose-finding studies in nude mice, the efficacy of P-4055 was highest when using schedules with repeated daily doses. In a Raji Burkitt's lymphoma leptomeningeal carcinomatosis model in nude rats, the control cytarabine- and saline-treated animals (five in each group) had a mean survival time of 13.2 days, whereas treatment with P-4055 resulted in three of five long-time survivors (>70 days). In a systemic Raji leukemia model in nude mice, 8 of 10 of the P-4055-treated animals survived (>80 days), compared with none of the cytarabine-treated animals (mean survival time, 34.2 days). In s.c. xenograft models, the effects of maximum tolerated doses of P-4055 and cytarabine, given in four weekly cycles of daily bolus i.v. injections for 5 subsequent days, against seven tumors (three melanomas, one lung adenocarcinoma, one breast cancer, and two osteogenic sarcomas) were investigated. P-4055 induced partial or complete tumor regression of the lung carcinoma, as well as of all three malignant melanomas. In two of the melanomas the activity was highly superior to that of cytarabine, and both P-4055 and cytarabine were, in general, more effective than several clinically established drugs previously tested in the same tumor models. In in vitro studies, inhibitors of nucleoside carrier-dependent transport, nitrobenzylmercaptopurine riboside and dipyridamol, reduced strongly the cellular sensitivity to cytarabine, but not to P-4055, indicating that P-4055 uses an alternative/additional mechanism of internalization into the cell compared with cytarabine. The results explain, at least in part, the observed differences between the two compounds in in vivo efficacy, and together the data strongly support the evaluation of P-4055 in clinical studies.