Synthesis and biological activities of 7-alkoxymitosanes.

A facile alcoholysis of 7-methoxymitosanes and 5-methoxyindolequinone under basic conditions was discovered and a series of 7-alkoxymitosanes were synthesized from mitomycins A and B using this reaction. They showed strong antibacterial activity against various Gram-positive and Gram-negative bacteria and were potent inhibitors of cultivating HeLa S-3 cells in vitro. Among them, 7-n-propoxy-7-demethoxymitomycin A (2) showed the strongest antitumor activity against solid type Sarcoma-180 in mice.

Antitumor activity of 7-N-phenyl derivatives of mitomycin C in the leukemia P388 system.

The antitumor activity of 7-N-phenyl derivatives of mitomycin C was tested in an ip-ip system of mouse leukemia P388 by single administration. The compounds tested were 7-N-phenyl-, 7-N-(p-aminophenyl)-, 7-N-(p-hydroxyphenyl)- and 7-N-(p-chlorophenyl)-mitomycin C. The maximum increases in life span (ILSmax) obtained were 124, 169, > 386 and 112%, respectively, that with mitomycin C being 104%. 7-N-(p-Hydroxyphenyl)-mitomycin C showed a higher ILS% than its ortho and meta isomers. Thus, 7-N-(p-hydroxyphenyl)-mitomycin C was the most effective of these compounds.

Electrostatic complexes of mitomycin C with nucleic acids and polyanions.

Reductively activated mitomycin C exhibits strong, non-covalent electrostatic binding to polyanions such as polyvinylsulfate and polyphosphate. The protonated C-2 amino group generated by the reduction is most likely responsible for this type of interaction. At moderate drug and salt concentrations only covalent binding to nucleic acids is observable. This is shown to be guanine-specific in DNA for the first time, as well as in synthetic polyribo- and polydeoxyribonucleotides at 10--20 times higher binding levels than previously tested. At higher mitomycin C concentration, however, strong non-covalent electrostatic binding to nucleic acids also occurs, resulting in a binding ratio up to 1 mol drug bound per mol mononucleotide, although this non-specific binding is relatively inhibited compared to polyvinylsulfate. Salts also have an inhibitory effect on the non-specific binding to nucleic acids. A series of mitomycin derivatives were compared for their binding and cross-linking abilities using DNA as substrate, with the following results: (a) the presence of a basic nitrogen . funtion at C-2 promotes binding, both covalent and electrostatic, presumably by kinetically facilitating the approach between positively charged nitrogen and DNA. (b) The aziridine ring is the major covalent binding site, indispensable for crosslinking and determines the guanine-specificity of the binding.

Mitomycin antibiotics. Synthesis of 7-methoxy-1-(N-pyrrolidino)mitosene and its methiodide.

7-Methoxy-1-(N-pyrrolidino)mitosene and its methiodide were synthesized. The latter compound was a potential bifunctional alkylating agent because of its two good leaving groups appropriately situated with respect to the indoloquinone chromophore. However, it was inactive in bacteriophage induction and P388 murine leukemia assays. Both compounds showed antibacterial activity in culture, and the former compound was very weakly active in inducing lysogenic bacteriophage.

[Research on substances with antiblastic activity. LXI. Synthesis of 6-amino- and 7-amino-9-keto-9H-pyrrolo[1,2-a]indole derivatives]. / Ricerche su sostanze ad attività antiblastica. Nota LXI. Sintesi di derivati del 6-amino- e del 7-amino-9-cheto-9H-pirrolo[1,2-a]indolo.

Intramolecular cyclization of 1-(2-carboxy-4-nitrophenyl)pyrrole afforded 7-nitro-9-oxo-9H-pyrrolo[1,2-a]indole, which was then reduced to 7-amino-9-oxo-9H-pyrrolo[1,2-a]indole. The same procedure was adopted for the synthesis of 6-amino-9-oxo-9H-pyrrolo[1,2-a]indole starting from 1-(2-carboxy-5-nitrophenyl)pyrrole. The preparation of some N-acylderivatives of the above cited aminoketones is reported. These compounds shall be subjected to biological screening against Leukemia L 1210 as a simple analogues of Mitomycin C.

Comparative stereochemistry in the aziridine ring openings of N-methylmitomycin A and 7-methoxy-1,2-(N-methylaziridino)mitosene.

A useful method was found for the conversion of mitomycin C into N-methylmitomycin A. The latter compound gave only two products on acid hydrolysis, the cis- and trans-1-hydroxy-7-methoxy-2-methylaminomitosenes. This selectivity allowed the cis--trans ratio to be quantitatively determined as 4:1. Such a predominance of the cis isomer is unexpected in view of the trans stereochemistry obtained in the opening of simple aziridines. In order to determine if the 9a-methoxy group of mitomycins controlled the direction of aziridine ring opening 7-methoxy-1,2-(N-methylaziridino)mitosene, which lacks this substituent, was prepared and hydrolyzed in acid. It gave the same two products in a 3:1 cis-trans ratio. In the induction of lambda-bacteriophage in Escherichia coli cis-1-hydroxy-7-methoxy-2-methylaminomitosene was more active than the corresponding trans isomer, but both of these compounds were less active than the aziridinomitosene or the mitomycins. Mitomycin A, mitomycin C, and N-methylmitomycin A were active against P388 leukemia in mice.

Mitomycin antibiotics. Synthesis and activity of 1,2-disubstituted mitosenes.

cis-1-Acetamido-2-acetoxy-7-methoxy-N-methylmitosene was prepared in 11 steps from 7-methoxy-6-methyl-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-one by a route involving bromination of the pyrrolidineenamine or trimethylsilyl enol ether of starting material, displacement of bromide by acetate, oxime formation, and reductive acetylation, followed by elaboration of the quinone and methyl carbamate functions according to previously established methods. An unsubstituted carbamate could not be prepared. The mitosene thus synthesized differs from previously reported 1,2-disubstituted mitosenes, which are derived from the solvolysis of mitomycins, in that it has the opposite arrangement of oxygen and nitrogen substituents at the 1 and 2 positions. It showed antibacterial activities in disk-plate assays superior to those of cis-diacetylapomitomycin A and equivalent to those of certain 1-substituted mitosenes; however, it was less active than mitomycin A in these assays. It was inactive in inducing lambda-bacteriophage in Escherichia coli and inactive against P388 leukemia in mice. In contrast, certain 1-substituted mitosenes were active in prophage induction and 2b and mitomycin A were active in both assays.

Structure and stereochemistry of some 1,2-disubstituted mitosenes from solvolysis of mitomycin C and mitomycin A.

Starting with mitomycin C (1), a number of solvolytic reactions were investigated and were found to result in opening of the aziridine ring with loss or migration of the 9a-methoxy group. A careful examination of the resulting 1,2-disubstituted 7-aminomitosenes indicated that there was a strong tendency for the azridine ring on opening to furnish mainly one stereoisomer, always with the oxygen stom at C-1 and the nitrogen atom at C-2. Thus the hydrolysis of 1withdition to small amounts of the trans-aminohydrin (10). Mitomycin A (2) BEHAVED ANALOGOUSLY. Both 1 and 2 generated a cis-1-acetoxy-2-acetamide when they were allowed to react with acetic anhydride. Acetolysis of mitomycin C was found to give the cis-1-hydroxy-2-acetamide (5), the trans-1-acetoxy-2-amine (14), and a cis-trans mixture of 1-acetoxy-2-acetamides (4 and 11, respectively). Routes to cis-1-methoxy-2-acetamide (9) were possible through the methanolysis of 1 or through the methylation of 5. For comparison, the trans-1-methoxy-2-acetamide (16) was obtained through a dnown resin-catalyzed methoxy migration from C-9A TO C-1 IN MITOMYCIN C. The use of 1-H nmr spectroscopy to asign configurations to 1,2-disubstituted mitosenes is discussed.