Synthetic nucleosides and nucleotides. XXXV. Synthesis and biological evaluations of 5-fluoropyrimidine nucleosides and nucleotides of 3-deoxy-beta-D-ribofuranose and related compounds.

1-O-Acetyl-2,5-di-O-p-chlorobenzoyl-3-deoxy-D-ribofuranose (1), derived from the antibiotic cordycepin was coupled with trimethylsilylated derivatives (2a-c) of N4-propionylcytosine, N4-p-toluoyl-5-fluorocytosine and 5-fluorouracil in the presence of trimethylsilyl trifluoromethanesulfonate (TMS-triflate) to give fully acylated nucleosides (3a-b and 3d, respectively). Selective removal of the N4-propionyl group of 3a by treatment with hydrazine hydrate gave 2',5'-di-O-p-chlorobenzoyl-3'-deoxycytidine (4). Deamination of 4 with sodium nitrite in trifluoroacetic acid afforded 2',5'-di-O-p-chlorobenzoyluridine (3c) in good yield. Compounds 3a-d were saponified to give free 3'-deoxycytidine (5a), 5-fluoro-3'-deoxycytidine (5b), 3'-deoxyuridine (5c), and 5-fluoro-3'-deoxyuridine (5d), respectively. These 3'-deoxyribonucleosides (5a-d) were then converted to corresponding 5'-monophosphate and further phosphorylated to the 5'-triphosphates by the phosphoroimidazolidate method. The nucleosides (5a-d) were examined for growth-inhibitory effects on mouse leukemic L5178Y cells, and their IC50 values (microgram/ml) were 1.8, 33, 6.5, and 18, respectively. On the other hand, the antiviral activities of these compounds on a rhabdovirus, infectious hematopoietic necrosis virus (IHNV), were moderate (IC50 = 100-500 micrograms/ml in CHSE-214 cells). The 5'-triphosphates showed remarkable inhibitory effects on DNA polymerase beta and DNA polymerase alpha-primase purified from testes of the cherry salmon, Oncorhynchus masou, but not on common DNA polymerase alpha from same source.

Three-month oral repeated administration toxicity study of seed saponins of Thea sinensis L. (Ryokucha saponin) in rats.

Ryokucha saponin (RSP), which is one of the ingredients of green tea, was administered orally to rats for 3 months at dose levels of 50, 150 and 500 mg/kg/day to assess any toxic effects. As positive control, 1200 mg/kg/day of quillaia saponin (QSP), which contains saponins equivalent in amount to those in 500 mg RSP/kg/day, was administered. The no-effect level of RSP was 50 mg/kg/day and the lowest-observed-effect level of RSP was 150 mg/kg/day for both sexes, so that the true no-effect level of RSP was estimated to be between these dose levels. In addition, it was confirmed that the toxicity of RSP at 500 mg/kg/day was less than that of QSP at 1200 mg/kg/day and RSP was demonstrated to be safer than QSP, which is a permitted food additive.

[Peri- and postnatal study on halopredone acetate in rats].

A peri- and postnatal study of halopredone acetate (THS-201), a synthetic corticosteroid, was carried out using Jcl: Wistar rats. Pregnant rats were treated subcutaneously in doses of 0.05, 0.4, 3.2 and 25.6 mg/kg/day, from day 17 of gestation to day 21 after delivery. All pregnant rats were allowed to litter naturally, and the postnatal development of offsprings was observed. The results obtained from the present study were as follows. No influences of THS-201 administration were observed on gestation, delivery and lactation of dams. THS-201 administration did not have any influences on viability and development, various functions such as reflex response, learning and reproductive performance of F1 generation, and further on development of F2 generation. Therefore, it was concluded that the non-effect dose of THS-201 for the reproduction of dams and development of F1 generation was 25.6 mg/kg/day.

[Teratogenicity study on halopredone acetate in rats].

A teratogenicity study of halopredone acetate (THS-201), a synthetic corticosteroid, was carried out using Jcl: Wistar rats. Pregnant rats were treated subcutaneously in doses of 0.1, 0.5, 2.5 and 12.5 mg/kg/day, from day 7 to day 17 of gestation. Two-thirds of pregnant rats were killed on day 20 of gestation to examine the development of fetuses, and remaining rats were allowed to litter naturally in order to investigate the postnatal development of offspring. The results obtained from the present study were as follows. During the gestation and lactation periods, there occurred a decrease in the maternal body weight gain in 2.5 and 12.5 mg/kg groups. No influences of THS-201 administration were observed on gestation, delivery and lactation of dams. No external, visceral and skeletal anomalies attributable to THS-201 were observed in the fetuses. THS-201 administration did not have any influences on viability and development, various functions such as reflex response, learning and reproductive performance of F1 generation, and further on development of F2 generation. Therefore, it was concluded that the non-effect dose of THS-201 for the reproduction of dams and development of F1 generation was 12.5 mg/kg/day.

[Fertility study on halopredone acetate in rats].

A fertility study of halopredone acetate (THS-201), a synthetic corticosteroid, was carried out using Jcl: Wistar rats. Male rats were treated subcutaneously for 63 days before mating and throughout mating, and female rats were treated subcutaneously for 14 days before mating and until day 7 of gestation, in doses of 0.04, 0.2, 1.0 and 5.0 mg/kg/day. Male and female rats in the same dose were mated. All of the pregnant rats were killed on day 20 of gestation and their fetuses were examined morphologically. The results obtained from the present study were as follows. A decrease in body weight gain was observed in male rats of 1.0 and 5.0 mg/kg groups, compared to the vehicle control group. In female rats of 5.0 mg/kg group, a decrease in body weight gain during gestation period was observed. However, no influences attributable to THS 201 administration were observed on the fertility and fetal development. These results indicated that the non-effect dose of THS-201 for the fertility of rats and fetal development was 5.0 mg/kg/day.