Antitumor studies. part 3: design, synthesis, antitumor activity, and molecular docking study of novel 2-methylthio-, 2-amino-, and 2-(N-substituted amino)-10-alkyl-2-deoxo-5-deazaflavins

Various novel 10-alkyl-2-deoxo-2-methylthio-5-deazaflavins have been synthesized by reaction of 6-(N-alkylanilino)-2-methylthiopyrimidin-4(3H)-ones with Vilsmeier reagent. The similar 2-(N-substituted amino) derivatives were prepared by nucleophilic replacement reaction of the 2-methylthio moiety by appropriate amines. The 2-oxo derivatives (i.e., 5-deazaflavins) were obtained by acidic hydrolysis of the 2-methylthio derivatives. The antitumor activities against CCRF-HSB-2 and KB cells and the antiviral activities against HSV-1 and HSV-2 have been investigated in vitro, and many compounds showed promising antitumor activities. Furthermore, AutoDock molecular docking into PTK has been done for lead optimization of these compounds as potential PTK inhibitors. Whereas, the designed 2-deoxo-5-deazaflavins connected with amino acids at the 2-position exhibited the good binding affinities into PTK with more hydrogen bonds.     

Antitumor studies. Part 1: design, synthesis, antitumor activity, and AutoDock study of 2-deoxo-2-phenyl-5-deazaflavins and 2-deoxo-2-phenylflavin-5-oxides as a new class of antitumor agents

Novel 2-deoxo-2-phenyl-5-deazaflavins and 2-deoxo-2-phenylflavin-5-oxides were prepared as a new class of antitumor agents and showed significant antitumor activities against NCI-H 460, HCT 116, A 431, CCRF-HSB-2, andKB cell lines. In vivo investigation, 2-deoxo-10-methyl-2-phenyl-5-deazaflavin exhibited the effective antitumor activity against A 431 human adenocarcinoma cells transplanted subcutaneously into nude mouse. Furthermore, AutoDock study has been done by binding of the flavin analogs into PTK pp60(c-src), where a good correlation between their IC(50) and AutoDock binding free energy was exhibited. In particular, 2-deoxo-2-phenylflavin-5-oxides exhibited the highest potential binding affinity within the binding pocket of PTK.     

Antitumor studies. Part 5: Synthesis, antitumor activity, and molecular docking study of 5-(monosubstituted amino)-2-deoxo-2-phenyl-5-deazaflavins

Various novel 5-(monosubstituted amino)-2-deoxo-2-phenyl-5-deazaflavins derivatives have been synthesized by direct coupling of 5-deazaflavins and N-alkyl or aryl amines. The antitumor activities against human tumor cell lines CCRF-HSB-2 and KB cells have been investigated in vitro and many compounds showed promising potential antitumor activities with less cytotoxicities. AutoDock molecular docking into PTK (PDB code: 1t46) has been done for lead optimization of these compounds as potential PTK inhibitors. Some of the synthesized 5-(monosubstituted amino)-2-deoxo-2-phenyl-5-deazaflavins at the 5-position exhibited reasonable binding affinities into PTK with the hydrogen bond through their C(5)-NH moiety.     

Synthesis, characterization and reactions of 2-deoxo-5-deazaalloxazines

5-Deazaflavins and their homologues have been known as potential riboflavin antagonists, bioreductives, and compounds with potent antitumor activity. 2-Amino-4-methylquinoline-3-carbonitrile (2) was prepared as unreported starting material for several interesting 2-deoxo-5-deazalloxazine derivatives. Cyclization of 2 using formamide afforded the 2,4-deoxo-5-deazaalloxazine derivative 7, which was subjected to deamination with nitrous acid to give the 2-deoxo-5-deazaalloxazine (8). The compound 8 was also obtained via 13 by treating the latter with refluxing formic acid or formamide and used as a precursor for synthesis of several 2-deoxo-5-deazaalloxazines 18, 19, 20, 21 and 22. The pharmacological and biological properties of these compounds are still under investigation.     

Novel synthesis of nicotinamide derivatives of cytotoxic properties

A variety of 2-substituted-4,6-diaryl-3-pyridinecarboxamides 5 were synthesized through aromatic nucleophilic substitution reaction of secondary amines with 2-bromo analogues 4. The latter were obtained via bromination of 2-cyano-3,5-diaryl-5-oxo-N-substituted pentamides 3 in glacial acetic acid. Moreover, pentamide derivatives 3 were prepared through base-catalyzed Michael addition of cyanacetanilides 2 with 1,3-diaryl-2-propen-1-ones 1. Otherwise, reaction of 2-bromo-3-pyridinecarboxamides 4 with primary aromatic amines in refluxing pyridine afforded the corresponding 2-(arylamino)-3-pyridinecarboxamides 6 besides the unexpected 2-unsubstituted amino analogues 7. Antitumor properties of the synthesized pyridinecarboxamides utilizing 59 different human tumor cell lines, representing leukemia, melanoma, and cancers of the lung, colon, brain, ovary, breast, prostate as well as kidney, were screened. Many of the tested compounds show considerable in vitro antitumor properties especially 5c and 7a, which reveal moderate activities against most of the used human tumor cell lines. It has also been achieved that, all the tested nicotinamide derivatives reveal promising antitumor properties against MDA-MB-231/ATCC (breast cancer).     

Synthesis and antitumor activity of 1- or 3-(alpha-hetero substituted)alkyl-5-fluorouracil derivatives

Two classes of 5-fluorouracil (5-FU) derivatives were prepared from 1,3-bis(hydroxymethyl)-5-fluorouracil (1). The first group was obtained by the direct esterification of 1 with various acids. The second one was derived by the nucleophilic substitution of N-(chloromethyl)-5-FUs, which were easily prepared by halogenation of 1, with hetero nucleophiles. The antitumor activities of the prepared compounds were examined against Leukemia L1210 and the results were compared with that of 1-hexylcarbamoyl-5-fluorouracil (HCFU, Carmofur).     

Synthesis and antihyperglycemic activity of suitably functionalized 3H-quinazolin-4-ones

A series of 2-sec-amino-3H-quinazolin-4-ones (4a-p) and 4-sec-amino-2-chloroquinazolines (5a-b) have been synthesized by nucleophilic substitution reaction of 2-chloro-4(3H)-quinazolones (3) and 2,4-dichloroquinazolines (2) with amines, respectively. Most of the synthesized compounds were evaluated for antihyperglycemic activity but only 4a,b,d,j,o displayed significant reduction in blood glucose level in streptozotocin and sucrose loaded rat models.     

Synthesis, antiviral and antitumor activity of 2-substituted-5-amidino-benzimidazoles

We have prepared a set of heterocyclic benzimidazole derivatives bearing amidino substituents at C-5 of benzimidazole ring, by introducing various heterocyclic nuclei (pyridine, N-methyl-pyrrole or imidazole) at C-2, and evaluated their antitumor and antiviral activities. The most pronounced antiproliferative activity was shown with compounds 6 and 9, having imidazolinylamidino-substituent. Interestingly, all compounds show noticeable selectivity toward breast cancer cell line MCF-7. The most distinct and selective antiviral activity toward coxsackieviruses and echoviruses was observed with compounds having pyridine ring at C-2. Especially interesting was fairly strong activity of 4 and 8 toward adenoviruses, which could be considered as leads against adenoviral replication.     

Synthesis, biological active molecular design, and molecular docking study of novel deazaflavin-cholestane hybrid compounds

Novel deazaflavin-cholestane hybrid compounds, 3',8'-disubstituted-5'-deazacholest-2,4-dieno[2,3-g]pteridine-2',4'(3'H,8'H)-diones, have been synthesized by condensation reaction between 6-(monosubstituted amino)-pyrimidin-2,4(1H,3H)-diones and 2-hydroxymethylenecholest-4-en-3-one in presence of p-toluenesulfonic acid monohydrate and diphenyl ether. The antitumor activities against human tumor cell lines (CCRF-HSB-2 and KB cells) have been investigated in vitro, and many of these compounds showed promising antitumor activities. Furthermore, molecular docking study using LigandFit within the software package Discovery Studio 1.7 was done for lead optimization of these compounds as potential PTK inhibitors. In general, all of the synthesized steroid-hybrid compounds showed good binding affinities into PTK (PDB code: 1t46).     

Syntheses and anti-cancer activities of 2-[1-(indol-3-yl-/pyrimidin-5-yl-/pyridine-2-yl-/quinolin-2-yl)-but-3-enylamino]-2-phenyl-ethanols

Schiff bases prepared by the reactions of substituted amines with indole-/, pyrimidine-/, pyridine-/, and quinoline-aldehydes are made to undergo indium mediated allylation whereby a (substituted amine, allyl)methyl group has been introduced at C-3 of indole, C-5 of pyrimidine, and C-2 of pyridine and quinoline. Amongst the 16 compounds investigated for anti-cancer activities at 59 human tumor cell lines 3, 9-12, and 14 show appreciable activities. The structure-activity relationship studies point that the contribution of phenylglycinol moiety as a part of side chain at C-3 of indole and C-5 of pyrimidine seems to be crucial for exhibiting anti-cancer activities.     

Synthesis of 2-bromomethyl-3-hydroxy-2-hydroxymethyl-propyl pyrimidine and theophylline nucleosides under microwave irradiation. Evaluation of their activity against hepatitis B virus

Alkylation of 2-methylthiopyrimidin-4(1H)-one (1a) and its 5(6)-alkyl derivatives 1b-d as well as theophylline (7) with 2,2-bis(bromomethyl)-1,3-diacetoxypropane (2) under microwave irradiation gave the corresponding acyclonucleosides 1-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]-2-methyl-thio pyrmidin-4(1H)-ones 3a-d and 7-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]theophylline (8), which upon further irradiation gave the double-headed acyclonucleosides 1,1 '-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis[(2-(methylthio)-pyrimidin-4(1H)-ones] 4a-c, and 7,7 '-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis(theophylline) (9). The deacetylated derivatives were obtained by the action of sodium methoxide. The activity of deacetylated nucleosides against Hepatitis B virus was evaluated. Compound 5b showed moderate inhibition activity against HBV with mild cytotoxicity.     

Novel 9a,11-bridged azalides: One-pot synthesis of N'-substituted 2-imino-1,3-oxazolidines condensed to an azalide aglycone

An efficient one-pot method for the synthesis of novel 9a,11-bridged 15-membered 9a-aza-9-deoxo-9a-homoerythromycin A and its 6-O-methyl analogue has been developed. The novel bicyclic azalide scaffold is characterized by an N′-substituted-2-imino-1,3-oxazolidine moiety bound to a macrolactone ring between positions 9a and 11. Removal of the cladinose sugar from the starting compounds allows easy preparation of a small series of such bicyclic 3-keto and 3,6-hemiketal azalide derivatives. A mechanism for the formation of N′-substituted-2-imino-1,3-oxazolidines is discussed. Antibacterial properties of the prepared compounds were evaluated.     

Synthesis and antimicrobial activity of 2-alkenylchroman-4-ones, 2-alkenylthiochroman-4-ones and 2-alkenylquinol-4-ones

2-Alkenylchroman-4-ones, 2-alkenylthiochroman-4-ones, and 2-alkenylquinol-4-ones were prepared with very good regioselectivity by Me3SiOTf-mediated conjugate addition of alkenylmagnesium bromides and alkenyllithium compounds to chromones thiochromones, and quinol-4-ones. A number of products exhibit a considerable antimicrobial activity. The best activity, with respect to the spectrum of antimicrobial activity, was observed for 2-vinylchroman-4-ones containing an unsubstituted vinyl group and a chloride group located at the chromanone moiety.     

Synthesis of 5-arylidene-2-amino-4-azolones and evaluation of their anticancer activity

Series of novel 5-arylidene-2-arylaminothiazol-4(5H)-ones and 2-aryl(benzyl)amino-1H-imidazol-4(5H)-ones were synthesized from appropriate 2-alkylthioazol-4-ones using nucleophilic substitution in position 2 by various anilines and benzylamines and Knoevenagel reaction. X-ray structural studies of 22 revealed the structure to be intermediate between amino and imino tautomeric forms. All the target compounds were evaluated for the anticancer activity in vitro in standard National Cancer Institute 60 cancer cell lines assay. Majority of compounds showed significant antitumor cytotoxicity effect at micromolar and submicromolar level (Mean Log GI₅₀ ranges ?5.77 to ?4.35). Some of the most potent compounds, namely 10 and 13, possessed selectively high effect on all leukemia cell lines at submicromolar level (Mean Log GI₅₀ [leukemia lines], respectively, ?6.41 and ?6.29), which are probably associated with immunosuppressive activity. Individual cancer cell lines sensitivity to synthesized compounds and SAR studies are discussed. COMPARE analysis allowed to disclose probable modes of anticancer action for synthesized compounds, in particular showed number of high correlations with activity patterns of alkylating agents (PCC ～ 0.606–0.731).     

Synthesis and pharmacological evaluation of 5H-[1]benzopyrano[4,3-d]pyrimidines effective as antiplatelet/analgesic agents

Synthesis and pharmacological screening of new 2-methylthio/2-methanesulfonyl/2-methoxy-5H-[1]benzopyrano[4,3-d]pyrimidines were planned in order to study the effects of the 5-substitution with alkoxy/phenoxy/alkylthio and phenylthio groups both on in vitro antiplatelet and in vivo antinociceptive activities. Antiplatelet activity was assessed in vitro against ADP, Arachidonic acid and U46619 induced aggregation, in rabbit plasma. Anti-inflammatory, analgesic and antipyretic activities were tested in rat paw edema, mouse writhing test and LPS induced rat fever, respectively. Amongst test compounds, 2-methylthio derivatives displayed an ASA-like antiplatelet activity whereas 2-methoxy and, particularly, 2-methanesulfonyl derivatives showed a broad spectrum of antiplatelet action, inhibiting both the ADP- and the AA- and U46619-induced aggregation. With regard to the in vivo pharmacological activities, mainly the 2-methoxy derivatives showed a significant analgesic effect comparable to that of indomethacin. SAR considerations, also in comparison with a number of previously described compounds, were performed.     

[Z]-4-alkylidene-1,3,2-benzodioxaphosphorinane 2-oxides from stereospecific cyclization of 2-alkylketophenyl phosphonates and phosphates

O,O-Di(2-alkylketophenyl) phenylphosphonates and O-(2-alkylketophenyl) O-O-diphenyl phosphates undergo facile cyclization at 70°C in acetonitrile containing K₂CO₃ to 2-phenyl- and 2-phenoxy-4-alkylidene-1,3,2-benzodioxaphosphorinane 2-oxides, respectively. The Z isomer is exclusively formed with higher alkylidene derivatives. Metabolically formed 4-alkylidene- and 4-methyl-1,3,2-benzodioxaphosphorinane 2-oxides may contribute to the biological activity of some 2-ethylphenylphosphorus compounds.     

Substituted E-3-(2-Chloro-3-indolylmethylene)1,3-dihydroindol-2-ones with antitumor activity

The synthesis and antitumor activity of a new series of E-3-(2-chloro-3-indolylmethylene)1,3-dihydroindol-2-ones is described. Several compounds were active on the primary test (three human cell lines) and entered the second level (60 human cell lines). All of them were potent growth inhibitors with GI(50) ranging from -5.32 to -7.27. Four are now under review by BEC (Biological Evaluation Committee of the NCI). The most potent antitumor derivatives were also evaluated as cardiotonic agents (in view of a possible coanthracyclinic activity). In order to find a possible mechanism of action their effects on cell cycle progression in an adenocarcinoma cell line (HT29) were tested, evidencing that these molecules are able to block HT29 in mitosis. The introduction of new substituents in the indolinone moiety while maintaining the same chloroindole portion generated interesting derivatives. 3-(2-Chloro-5-methoxy-6-methyl-3-indolylmethylene)5-hydroxy-1,3-dihydroindol-2-one was the most active of the whole series. It was more potent than vincristine against seven of the nine tumors considered. Moreover it was selective towards some cell lines such as MDA-MB-435 (breast), OVCAR-3 (ovarian) and SK-MEL-28 (melanoma). Even the introduction of a benzyl ring at the nitrogen of the chloroindole portion, gave rise to potent compounds.