Abstract: Disclosed is a method for removing a protective group of an N-protected tetrazolyl compound which comprises reacting said N-protected tetrazolyl compound with a mineral acid under substantially anhydrous conditions in the presence of an alcohol, insuring a high reaction yield of the object tetrazolyl compound.

Abstract: Disclosed are a compound of the formula (R).sub.3 SnN.sub.3, wherein R is a C.sub.7-18 alkyl, and a process for producing a tetrazolylbenzene compound which comprises reacting a cyanobenzene compound with a (R).sub.3 SnN.sub.3. This process is useful for a safe and commercially profitable production of the tetrazolylbenzene compound which is employed for producing a tetrazole derivative having a hypotensive action based on angiotensin II-antagonizing activity or a production intermediate thereof.

Abstract: Disclosed is a method for removing a protective group of an N-protected tetrazolyl compound which comprises reacting said N-protected tetrazolyl compound with a mineral acid under substantially anhydrous conditions in the presence of an alcohol, insuring a high reaction yield of the object tetrazolyl compound.

Abstract: 5-Aminoflavone derivatives represented by the formula (I): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are the same or different and represent hydrogen, substituted or unsubstituted lower alkyl, lower alkenyl, halogen-substituted or unsubstituted lower alkanoyl or lower alkoxycarbonyl, X.sup.1, X.sup.2, Y.sup.1 and Y.sup.2 are the same or different and represent hydrogen, halogen or lower alkyl, at least one of X.sup.1 and X.sup.2 represents halogen or lower alkyl, X.sup.3 represents hydrogen, substituted or unsubstituted lower alkyl, lower alkenyl, lower alkynyl, halogen, hydroxy, substituted or unsubstituted lower alkoxy, NR.sup.5 R.sup.6 (wherein R.sup.5 and R.sup.6 are the same or different and represent hydrogen, or substituted or unsubstituted lower alkyl, or R.sup.5 and R.sup.

Abstract: Disclosed are a compound of the formula (R).sub.3 SnN.sub.3, wherein R is a C.sub.7-18 alkyl, and a process for producing a tetrazolylbenzene compound which comprises reacting a cyanobenzene compound with a (R).sub.3 SnN.sub.3. This process is useful for a safe and commercially profitable production of the tetrazolylbenzene compound which is employed for producing a tetrazole derivative having a hypotensive action based on angiotensin II-antagonizing activity or a production intermediate thereof.

Abstract: Disclosed is pyrazoloacridone derivatives represented by formula (I): ##STR1## wherein: each of R.sup.1a, R.sup.1b, R.sup.1c and R.sup.1d independently represents hydrogen, lower alkyl, --(CH.sub.2).sub.p --Xwherein p represents an integer of 1 to 6, and X represents hydroxy, lower alkoxy or --NR.sup.2a R.sup.2bwherein each of R.sup.2a and R.sup.2b independently represents hydrogen, lower alkyl, or --(CH.sub.2).sub.m --Ywherein m represents an integer of 1 to 6, and Y represents hydroxy, lower alkoxy or --NR.sup.3a R.sup.3bwherein each of R.sup.3a and R.sup.3b independently represents hydrogen or lower alkylor --CH[(CH.sub.2).sub.n OH].sub.2wherein n represents an integer of 1 to 5; or a pharmaceutically acceptable salt thereof.

Abstract: Novel pyrazoloacridone compounds represented by the following formula: ##STR1## and pharmaceutically acceptable salts thereof have an excellent anti-tumor activity.

Abstract: Mitomycin derivatives having potent anti-tumor activity against solid sarcoma 180 tumors and lymphocytic leukemia P-388 tumors.