Nippon Kayaku Kabushiki Kaisha

Takemitsu Nagahata

Kenichi Matsubara

Hiroo Hoshino

Yukihiro Nishiyama

Seiichi Saito

Katsutoshi Takahashi

Nobuyoshi Shimada

Shigeru Hasegawa

Jun-ichi Seki

Akira Shiozawa

Yuh-ichiro Ichikawa

Yuka Sugawara

Hiroshi Akaba

Akio Fujii

Hideo Sugimura

Masayuki Kitagawa

Kazuhisa Narita

Takayuki Tomizawa

Kouwa Yamashita

Kyoichi Shibuya

Sayuri Kato

A novel nucleic acid derivative represented by the following general formula (I) and physiologically acceptable salt thereof which are expected to have an antiviral activity: ##STR1## wherein B represents a nucleic acid base derivative; A.sup.1 and A.sup.2 represent, independently of each other, OR.sup.1 or OCOR.sup.1 ; R.sup.1 represents a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group; l represents a number of 0 or 1; and m and n each represents an integer of 0-2; provided that when l and m are 0, n is 0 or 2.

Adenine and guanine derivatives for the treatment of hepatitis virus

This invention relates to cyclobutane derivatives represented by the following general formula (1) and physiologically acceptable salts thereof: ##STR1## wherein B represents a nucleic acid base derivative, R.sup.1 and R.sup.2 independently represent hydrogen atom, dialkylaminoacyl group, 1,4-dihydro-1-methylnicotinoyl group or substituted phosphoric acid group, provided that either one of R.sup.1 and R.sup.2 is a group other than hydrogen atom. The compounds of this invention exhibit a high oral absorbability and are metabolized in vivo into the compounds of formula (1a). Accordingly, the compounds of this invention are expectedly useful as antiviral agent.

Phenoxyphosphoryloxymethyl cyclobutyl purines

This invention relates to novel oxetanocins represented by the following general formula (I): ##STR1## wherein R represents a group represented by ##STR2## and their pharmacologically acceptable salts which have antiviral activities.

Oxetanocins

The present invention relates to phosphoric acid esters of oxetanocins having an antiviral activity which are represented by general formula (I): ##STR1## wherein R.sub.1 represents a phosphoric acid ester residue, X represents hydrogen, hydroxy or hydroxymethyl group, and B represents a purine base residue, and pharmacologically acceptable salts thereof.

Antiviral phosphoric acid esters of oxetanocins

This invention relates to oxetanocin-related compounds represented by the following formula (I): ##STR1## [in formula (I), R.sub.1, Y and B have the following meanings: (a) R.sub.1 represents --CH.sub.2 OH or --CH.sub.2 OCO-(alkyl),

Oxetanocin-related compounds and pharmaceutical compositions containing

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Toyonaka, Japan

Takemitsu Nagahata