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Biomedical subjects

N Katagiri

Publications and source records attributed to N Katagiri.

At least 37 records · Page 2Linked to original sources
PubMed1993

Remarkable acceleration for the deamination of carbocyclic purine nucleosides by adenosine deaminase under high-pressure.

Deamination of an anti-HIV carbocyclic adenine nucleoside, 9-[c-4,t-5-bis(hydroxymethyl)cyclopent-2-en-r-1-yl]-9H-adenine [(+/-)-BCA] and (+/-)-diamino-carbovir by adenosine deaminase under high-pressure (4 kbar) was carried out. Deamination of the former gave the corresponding (-)-hypoxanthine derivative whereas that of the latter produced (-)-carbovir having anti-HIV activity. The enantiomeric excess (e.e.) of both products was nearly 100%.

Adenine↗
PubMed1992

Synthesis and anti-HIV activity of 9-[c-4,t-5-bis(hydroxymethyl)cyclopent-2-en-r-1-yl]-9H-adenine.

The synthesis and in vitro anti-HIV activity of two new racemic nucleoside analogues are described; namely, 9-[c-4,t-5-bis(hydroxymethyl)cyclopent-2-en-r-1-yl]-9H-adenine (12) and its guanine analogue 18. While the latter (18) showed no activity, the therapeutic index of the former (12) was 200 and comparable to that (400) of carbovir. One enantiomer of 12 may be viewed as an analogue of carbocyclic oxetanocin and the other as an analogue of carbovir. Hence, these results indicate that one or both of the individual enantiomers of 12 could serve as candidates or lead compounds for the development of anti-AIDS agents.

Adenine↗
PubMed1992

Resolution of 9-(c-4,t-5-bishydroxymethylcyclopent-2-en-r-1-yl)-9H-adenine and selective inhibition of human immunodeficiency virus by the (-) enantiomer.

Two enantiomers of 9-(c-4,t-5-bishydroxymethylcyclopent-2-en-r-1-yl)-9H- adenine (BCA) which showed a potent and selective anti-HIV effects have been synthesized and evaluated against human immunodeficiency virus type 1. The result demonstrated that the potent-HIV activity of racemic BCA is expressed solely by the (-) isomer.

Adenine↗
PubMed1992

High pressure mediated Diels-Alder reaction using 2-iminomalonates as dienophiles: novel synthesis of carbocyclic nucleosides.

9-[c-4-(1,2-Dihydroxyethyl)cyclopent-2-en-r-1-yl]-9H-adenine , an isomer of BCA, has been synthesized from Diels-Alder adducts prepared by the reaction of 2-iminomalonates with cyclopentadiene under high pressure. The synthetic method involves a novel C-N bond cleavage reaction by NaBH4-K2CO3 (RRA reaction conditions) and has wide applicability for the synthesis of various carbocyclic nucleosides.

Adenine↗
PubMed1991

The nucleoside derivatives possessing sedative and hypnotic effects.

N3-Substituted oxopyrimidines and their related compounds were synthesized. The central nervous system (CNS) depressant activities of the compounds such as hypnotic activity and barbiturate-induced narcosis have been evaluated. N3-Benzyl, o,m,p-xylyl, alpha-phenylethyl, phenacyl substituted and related oxopyrimidine nucleosides exhibited potent hypnotic activity by intracerebroventricular (i.c.v.) administration to mice. The results indicate that hypnotic action of oxopyrimidine nucleoside derivatives might relate to functional group at the N3 position on oxopyrimidine ring and stereospecificity of sugar moiety.

Animals↗
PubMed1985

Synthesis of optically active beta-lactams using the photochemical reaction of 3-deazauridines.

The photochemical reaction of 3-deazauridines was investigated with the intention of obtaining chiral beta-lactams. Irradiation of appropriately protected 3-deazauridines at greater than or equal to 300 nm gave 2-(protected D-ribofuranosyl)-3-oxo-2-azabicyclo[2.2.0]hex-5-enes as a mixture of diasteromers, which were chromatographically separable. Treatment of each isomer with acid, such as trifluoroacetic acid, afforded the 5-oxo derivatives which by methanolysis gave rise to the corresponding chiral 4-methoxy-carbonylmethyl-1-(protected D-ribofuranosyl)azetidin-2-ones in good yields.

3-Deazauridine↗
PubMed1981

[Close classification method of undetermined cases of trophoblastic disease (author's transl)].

With the improvement of recovery ratio of trophoblastic disease by means of primary chemotherapy, undetermined cases of trophoblastic diseases, whose morphological examination has not been conducted, have increased. The respective sickly constitutions of these cases are extremely complicated, and we have deviced a new close classification of these cases from clinical standpoint. For the purpose, we have chosen out the following items.: A. Major subdivision 1. Types of antecident pregnancy. 2. Duration between the antecident pregnancy and the commencement of chemotherapy. 3. Urinary hCG secretion pattern following molar pregnancy. 4. Following treatment of hydatidiform mole. B. Minor subdivision 1. Urinary hCG titer at the commencement of chemotherapy. 2. BBT pattern. 3. Chest x-ray findings. 4. PAG. 5. Clinical signs. 6. Development of focuses (clinical). 7. Necessary reasons for chemotherapy. These items are expressed respectively by figures. This close classification method is based on the combinations of these figures. The authors believe, this method will enable the easy classification of early chemotherapy examples and will present a strong key for the analysis of enormous cases.

Chorionic Gonadotropin↗
PubMed1976

Chemical and enzymatic synthesis of lactose operator of Escherichia coli and its binding to lactose repressor.

The 21-nucleotide-long duplex DNA constituting the lactose operator sequence of E. coli has been synthesized by both chemical and enzymatic methods. The synthetic duplex has the essential feature of the lactose operator as seen by its binding to the lactose repressor. The binding of the synthetic operator fragment to the lactose repressor is specific because it is inhibited by the inducing ligand isopropyl-beta-D-thiogalactoside. Thus, it is now possible to show that a chemically synthesized oligodeoxynucleotide can be specifically recognized by its natural regulatory protein.

Bacterial Proteins↗