Nippon Kayaku Kabushiki Kaisha

Jun-ichi Seki

Hiroo Hoshino

Seiichi Saito

Nobuyoshi Shimada

Kenichi Matsubara

Yukihiro Nishiyama

Takemitsu Nagahata

Katsutoshi Takahashi

Masayuki Kitagawa

Shigeru Hasegawa

Akira Masuda

Akira Shiozawa

Yuh-ichiro Ichikawa

Yuka Sugawara

Hiroshi Akaba

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

It was found that 2-halogeno-oxetanocin A and 4'-phosphate thereof represented by the following general formula (1): ##STR1## wherein X represents a halogen atom and R represents a hydrogen atom or a phosphoric acid residue ##STR2## or salts thereof exhibit a strong antiviral activity and are useful as an active ingredient of therapeutic drug for viral diseases. Further, it was also found that the compounds of this invention are characterized in that they are not inactivated by adenosine deaminase widely present in living bodies and exhibit a high residual activity.

2-halogeno-oxetanocin A and phosphoric ester thereof

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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Takasaki, Japan

Jun-ichi Seki