Abstract: A polyprenyl carboxylic acid compound represented by the following general formula: ##STR1## wherein R stands for a hydrogen atom or an alkyl, alkenyl, cycloalkyl or aryl group, and n is an integer of 6 to 11. This compound is effective to treat hypertension of warm blooded animals.

Abstract: Novel 5-fluorouracil derivatives of the general formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 each represent hydrogen atom or methyl group, and R.sub.4 represents a straight or branched alkyl or alkenyl group, which has low toxicity and improved antitumor activity, and novel antitumor preparations containing the said 5-fluorouracil derivative.

Abstract: A polyprenyl carboxylic acid compound represented by the following general formula: ##STR1## wherein R stands for a hydrogen atom or an alkyl, alkenyl, cycloalkyl or aryl group, and n is an integer of 6 to 11. This compound is effective to treat hypertension of warm blooded animals.

Abstract: A process for synthesizing 2,3-dimethoxy-5-methyl-6-substituted-1,4-benzoquinones having the formula: ##STR1## wherein R is ##STR2## in which n is an integer of 0 to 9, and A and B are hydrogens or taken together form a valence bond,In which 2-methyl-4,5,6-trimethoxyphenol is reacted with boric acid or a reactive derivative thereof to obtain a 2-methyl-4,5,6-trimethoxyphenol ester of boric acid, reacting the resulting ester with an n-prenol or iso-prenol having the formula: ##STR3## wherein R is as defined above, OR A REACTIVE DERIVATIVE OF SAID N- OR ISO-PRENOL, IN THE PRESENCE OF A SILICA-ALUMINA COMPOUND, TO OBTAIN A 2-METHYL-3-SUBSTITUTED-4,5,6-TRIMETHOXYPHENOL ESTER OF BORIC ACID, AND HYDROLYZING THE THUS-OBTAINED ESTER AND TREATING THE RESULTING 2-METHYL-3-SUBSTITUTED 4,5,6-TRIMETHOXYPHENOL HAVING THE FORMULA: ##STR4## wherein R is as defined above, with an oxidant.

Abstract: A process for the synthesis of 2,3-dimethoxy-5-methyl-6-substituted-1,4-benzoquinones having the formula: ##STR1## wherein R is ##STR2## in which n is an integer of 0 to 9, and A and B are hydrogens or A--B is a direct valence bond between the carbon atoms to which they are attached,Characterized by reacting 2-methyl-4,5,6-trimethoxyphenol with an aryl boronic acid, a lower alkyl boronic acid or an acid anhydride thereof to obtain a 2-methyl-4,5,6-trimethoxyphenol ester of boric acid, reacting the resulting ester with an n-prenol or iso-prenol having the formula: ##STR3## wherein R is as defined above, OR A REACTIVE DERIVATIVE OF SAID N- OR ISO-PRENOL, IN THE PRESENCE OF A SILICA-ALUMINA COMPOUND, TO OBTAIN A 2-METHYL-3-SUBSTITUTED-4,5,6-TRIMETHOXYPHENOL ESTER OF BORIC ACID, AND HYDROLYZING THE THUS-OBTAINED ESTER AND TREATING THE RESULTING 2-METHYL-3-SUBSTITUTED-4,5,6-TRIMETHOXYPHENOL HAVING THE FORMULA: ##STR4## wherein R is as defined above, WITH AN OXIDIZING AGENT.

Abstract: 2,3-DIMETHOXY-5-METHYL-6-SUBSTITUTED-1,4-BENZOQUINONE HAVING THE FORMULA: ##STR1## in which S is an integer of 0 to 11 and A and B stand for hydrogen or may form a direct bond,Is prepared by reacting boric acid ester of 2,3-dimethoxy-5-methyl-1,4-benzohydroquinone with prenol or isoprenol having the above group R and subsequently reacting the resulting borate with a mild oxidant. The compound is useful as coenzyme Q and has various clinical effects.

Abstract: 2,3-DIMETHOXY-5-SUBSTITUTED-6-METHYL-1,4-BENZOHYDROQUINONE OR 1-MONOESTER THEREOF IS PREPARED BY REACTING 2,3-DIMETHOXY-6-METHYL-1,4-BENZOHYDROQUINONE OR 1-MONOACYLESTER THEREOF WITH PRENOL, ISOPRENOL OR DERIVATIVES THEREOF IN THE PRESENCE OF AN ACIDIC CATALYST FOR CONDENSATION WHICH IS ADSORBED ON AN ADSORBENT. This obtained compound is easily converted to quinone compounds which produces many clinical effects in medical and pharmaceutical uses.

Abstract: 2,3-DIMETHOXY-5-METHYL-6-SUBSTITUTED-1,4-BENZOQUINONE HAVING THE FORMULA: ##STR1## in which R is ##STR2## in which S is an integer of 0 to 11 and A and B stand for hydrogen or may form a direct bond, is prepared by reacting a boric acid ester of 2,3-dimethoxy-5-methyl-1,4-benzohydroquinone with prenol or isoprenol having the above group R and subsequently reacting the resulting borate with a mild oxidant. The compound is useful as coenzyme Q and has various clinical effects.