An efficient synthesis of indolo[2,3-b]quinoline guanidine derivatives with their in vitro and in vivo study.

An optimization of the guanidylation process by verifying the efficacy of common guanylation reagents in order to obtain the guanidine derivatives of indolo[2,3-b]quinoline has been performed. As a result, a high-yield procedure using N,N'-di-Boc-N''-triflylguanidine was applied to synthesize the guanidine derivative of indolo[2,3-b]quinoline 1 in a gram scale for specific in vitro and in vivo biological research. Extensive studies on the antiproliferative activity against eight human tumor cell lines were completed. Compound 1 revealed the highest activity against A549 lung adenocarcinoma and MCF7 breast cancer cell lines. Thus, 1 was evaluated for the in vivo anticancer activity against 4T1 mammary gland carcinoma and KLN205 murine lung carcinoma in mouse models. The anticancer effect was observed in the KLN205 model with a 37% tumor growth inhibition at the 20 mg/kg dose. This anticancer activity of 1 was comparable to that of cyclophosphamide which inhibited murine lung tumor growth in the range of 27-43% at the dose of 100 mg/kg. The biochemistry research after 1 admission, including measurements of blood parameters like alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and urea and creatinine, were also performed.

Synthesis and physicochemical characterization of the impurities of pemetrexed disodium, an anticancer drug.

A physicochemical characterization of the process-related impurities associated with the synthesis of pemetrexed disodium was performed. The possibility of pemetrexed impurities forming has been mentioned in literature, but no study on their structure has been published yet. This paper describes the development of the synthesis methods for these compounds and discusses their structure elucidation on the basis of two-dimensional NMR experiments and MS data. The identification of these impurities should be useful for the quality control during the production of the pemetrexed disodium salt.

Synthesis and Physicochemical Characterization of the Process-Related Impurities of Olmesartan Medoxomil. Do 5-(Biphenyl-2-yl)-1-triphenylmethyltetrazole Intermediates in Sartan Syntheses Exist?

During the process development for multigram-scale synthesis of olmesartan medoxomil (OM), two principal regioisomeric process-related impurities were observed along with the final active pharmaceutical ingredient (API). The impurities were identified as N-1- and N-2-(5-methyl-2-oxo-1,3-dioxolen-4-yl)methyl derivatives of OM. Both compounds, of which N-2 isomer of olmesartan dimedoxomil is a novel impurity of OM, were synthesized and fully characterized by differential scanning calorimetry (DSC), infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrometry/electrospray ionization (HRMS/ESI). Their ¹H, (13)C and (15)N nuclear magnetic resonance signals were fully assigned. The molecular structures of N-triphenylmethylolmesartan ethyl (N-tritylolmesartan ethyl) and N-tritylolmesartan medoxomil, the key intermediates in OM synthesis, were solved and refined using single-crystal X-ray diffraction (SCXRD). The SCXRD study revealed that N-tritylated intermediates of OM exist exclusively as one of the two possible regioisomers. In molecular structures of these regioisomers, the trityl substituent is attached to the N-2 nitrogen atom of the tetrazole ring, and not to the N-1 nitrogen, as has been widely reported up to the present. This finding indicates that the reported structural formula of N-tritylolmesartan ethyl and N-tritylolmesartan medoxomil, as well as their systematic chemical names, must be revised. The careful analysis of literature spectroscopic data for other sartan intermediates and their analogs with 5-(biphenyl-2-yl)tetrazole moiety showed that they also exist exclusively as N-2-trityl regioisomers.

New Polymorphic Forms of Pemetrexed Diacid and Their Use for the Preparation of Pharmaceutically Pure Amorphous and Hemipentahydrate Forms of Pemetrexed Disodium.

The preparation of stable amorphous pemetrexed disodium of pharmaceutical purity as well as the process optimization for the preparation of the hemipentahydrate form of pemetrexed disodium are described. Analytical methods for the polymorphic and chemical purity studies of pemetrexed disodium and pemetrexed diacid forms were developed. The physicochemical properties of the amorphous and hydrate forms of pemetrexed disodium, as well as new forms of pemetrexed diacid (a key synthetic intermediate) were studied by thermal analysis and powder X-ray diffraction. High-performance liquid chromatography and gas chromatography methods were used for the chemical purity and residual solvents determination. In order to study the polymorphic and chemical stability of the amorphous and hemipentahydrate forms, a hygroscopicity test (25 °C, 80% RH) was performed. Powder diffraction and high-performance liquid chromatography analyses revealed that the amorphous character and high chemical purity were preserved after the hygroscopicity test. The hemipentahydrate form transformed completely to the heptahydrate form of pemetrexed disodium. Both pemetrexed disodium forms were produced with high efficiency and pharmaceutical purity in a small commercial scale. Amorphous pemetrexed disodium was selected for further pharmaceutical development. Two new polymorphs (forms 1 and 2) of pemetrexed diacid were used for the preparation of high purity amorphous pemetrexed disodium.

The synthesis of indolo[2,3-b]quinoline derivatives with a guanidine group: highly selective cytotoxic agents.

The synthesis of indolo[2,3-b]quinoline derivatives containing guanidine, amino acid or guanylamino acid substituents as well as their in vitro evaluation for the cytotoxic and antifungal activity are reported. The influence of the guanidine group on the selective cytotoxic and hemolytic properties of indolo[2,3-b]quinoline was investigated. Most of the compounds displayed a high cytotoxic activity in vitro and two of the most promising compounds (3 and 12) exhibited a high selectivity between normal and cancer cell-lines. The cytotoxic activity of compound 3 was about 600-fold lower against normal fibroblasts than against A549 and MCF-7 cancer cell lines. Novel entities acted as the DNA-intercalators when tested using a DNA-methyl green assay but demonstrated zero or low hemolytic activity in comparison to their unsubstituted analogs. The mechanism of action was studied for guanidine derivatives 3 and 12 and both compounds were found to be very effective inducers of apoptosis.