Synthesis and Characterization of Macrocyclic Chiral Tröger’s Base Phenhomazine Candidates as Anticancer Agent

1,4,7,10-Tetraoxa[10](2,8)trögerophane 5 was synthesized from its corresponding precursors. Heating of 2 with p-nitrophenoxide afforded bis(p-nitrophenyl)ether 3, which was treated with hydrazine hydrate to give bis(p-aminophenyl)ether 4. Treatment of 4 with paraformaldehyde and triflouroacetic anhydride gave trögerophane 5. Reaction of 5 with trifluroacetic anhydride afforded phenhomazine derivative 6, which was treated with potassium carbonate to afford tetrahydrophenhomazine 7. Finally, reaction of 7 with phenacylchloride, bromoacetic acid, or ethyl bromoacetate in the presence of triethyl amine under reflux, afforded the corresponding macrocyclic compounds 8, 9 and 10, respectively. The synthesized trögerophane,precursors and its newly synthesized phenhomazines derivatives were screened for anticancer activity. Results revealed that 1,4,7,10-tetraoxa[10](2,8)trögerophane had a promising selectivity towards colon cancer cell line with an IC50 of 92.7 µg/ml.

Orthoamide und Iminiumsalze, IIC. Darstellung von N-(ω-Ammonioalkyl)-N,N′,N′,N″,N″-peralkylierten Guanidiniumsalzen und N-(ω-Aminoalkyl)-N′,N′,N″,N″-tetramethylguanidinen

N,N,N′,N′-Tetraalkylchlorformamidiniumchlorides 1a, b react with ω-dimethylaminoalkylamines 19, 20 to give mixtures of N-(ω-dimethylammonioalkyl)-guanidinium salts 12, 13 and N-(ω-dimethylaminoalkyl)-guanidinium salts 21, 22. These mixtures are transformed to mixtures of the ureas 15, 17 and N-(ω-dimethylaminoalkyl)-guanidines 23, 25 on treatment with aqueous sodium hydroxide. The reaction of N-(3-dimethylammoniopropyl)-guanidin 25a with dimethylsulfate in a molar ratio of 1:1 delivers a mixture of the N-(3-dimethylaminopropyl)-N,N,N′,N′,N″,N″-pentamethyl-guanidinium salt 29a and the N-(3-dimethylammoniopropyl)-N,N′,N′,N″,N″-pentamethyl-guanidinium-bis (methylsulfate) 33a. The action of dimethylsulfate on the guanidines 23a, 25a in a molar ratio of 2:1 affords the bisquarternary salts 32a, 33a. Alkylating reagents as methyliodide, benzylbromide, allylbromide and chloroacetonitrile attack N-(2-dimethylaminoethyl)-N′,N′,N″,N″-tetraethylguanidine (23b) in a molar ratio of 1:1 cleanly at the dimethylaminoethylgroup to give the ammonium salts 30a–d. As a strong base the guanidine 23b dehydrochlorinates β-Chlorpropionitrile and chloroacetone under formation of the guanidinium salt 21c. In contrast to this the reaction of ethyl bromoacetate with the N-(2-dimethylaminoethyl)guanidine 23b occurs at the guanidinogroup giving the guanidinium salt 28c. The methylation of the guanidinium chlorides 21a, 22a with dimethyl sulfate affords the bis-quaternary salts 35b, 36b with mixed anions. From the heterocyclic guanidines 14, 16 and the alkylating reagents benzylbromide and ethyl bromoacetate the heterocyclic guanidinium salts 37a, b, 39a, b can be obtained. The reactions with ethyl chloroformiate proceed in an analogous way giving the guanidinium salts 37c, 39c. The N-alkyl-N,N,N′,N′-tetramethyl-(3-ureidopropyl)guanidinium salts 41a, b can be prepared from the N′,N′,N″,N″-tetramethyl-N′′-(3-ureidopropyl) guanidine 17a and the alkylating compounds dimethyl sulfate and benzyl bromide. Several compounds obtained that way were transformed to the corresponding tetraphenyloborates and bis(tetraphenylborates), respectively.

Synthesis and In Vitro Anti-Toxoplasma gondii Activity of Novel Thiazolidin-4-one Derivatives

Recent findings on the biological activity of thiazolidin-4-ones and taking into account the lack of effective drugs used in the treatment of toxoplasmosis, their numerous side effects, as well as the problem of drug resistance of parasites prompted us to look for new agents. We designed and synthesized a series of new thiazolidin-4-one derivatives through a two-step reaction between 4-substituted thiosemicarbazides with hydroxybenzaldehydes followed by the treatment with ethyl bromoacetate; maleic anhydride and dimethyl acetylenedicarboxylate afforded target compounds. The thiazolidin-4-one derivatives were used to assess the inhibition of Toxoplasma gondii growth in vitro. All active thiazolidine-4-one derivatives (12 compounds) inhibited T. gondii proliferation in vitro much better than used references drugs both sulfadiazine as well as the synergistic effect of sulfadiazine + trimethoprim (weight ratio 5:1). Most active among them derivatives 94 and 95 showed inhibition of proliferation at about 392-fold better than sulfadiazine and 18-fold better than sulfadiazine with trimethoprim. All active compounds (82–88 and 91–95) against T. gondii represent values from 1.75 to 15.86 (CC30/IC50) lower than no cytotoxic value (CC30).

Microwave-Assisted Synthesis of Chiral Oxime Ethers

An efficient and rapid synthesis of a new class of chiral oxime ethers has been achieved via two-step reaction in which the first step is the reaction of oximes 1a-f with ethyl bromoacetate in the presence of sodium hydride to give oxime ethers 2a-f which are subsequently, in the second step, reacted with different commercially available chiral amines under microwave irradiation conditions to give compounds 3a-l in good to excellent yields. Through this method, we have observed a decrease in reaction time and excellent yields than the previously described conventional method.

Synthesıs and Characterızatıon of New Trıazole and Coumarın-Derived Heterocyclıc Compounds Part I

Synthesis of ethyl ester of acetic acid containing 5-oxo-[1,2,4] triazole ring (2) was achieved by the condensation of 3-substituted-4-amino-1H-1,2,4-triazol-5(4H)-one (1) with ethyl bromoacetate in basic medium. Compound 2, was then further reacted with hydrazine hydrate to form acid hydrazide, which is 2-(4-amino-3-substituted-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)acetohydrazide (3). Compound 3 was later treated with three different diverse coumarin aldehydes (6, 12, 18) resulted in the formation of arylidene hydrazides as cis–trans conformers (7, 8, 13, 14, 19, 20). In conclusion, we synthesized 1,2,4-triazole Schiff bases derived from the condensation of 3-substituted-4-amino-1,2,4-triazole-5-on and formylhydroxy-4-methylcoumarin derivatives, which have been characterized by, spectroscopic measurements (IR, 1H-NMR, 13C-NMR and elemental analysis).

Synthesis and transforming of 3-cyclohecxyl-4-formylsydnone N-(2’,3’,4’,6’-tetra-O-acetyl-β-D-glucopyranosyl)thiosemicarbazon compound from cyclohexynlamine

The thiosemicarbazone compound (6) contains heterocyclic sydnone, was synthesized from cyclohexylamine (1) by microwave irradiation method, yield 85%. From the thiosemicarbazone compound (6), we performed cyclization reaction of thioure group with ethyl bromoacetate, in ethanol solvent and sodium acetate catalyst, in 46 hours, obtained the thiazolidine-4-one (7), yield 68%. When performing the cyclization reaction of imine group with acetic anhydride, in dichloromethane solvent, in 46 hours, obtained 4,5-dihydro-1,3,4-thiadiazol derivatives (8), yield 60%. For thiosemicarbazone (6) reacts with zinc acetate at room temperature, in a solvent of ethanol, about 3 hours, obtained the bis [thiosemicarbazonato] zinc(II) complex (9), yield 80%. Structures of thiosemicarbazone derivatives (6), thiazolidin-4-on (7), 4,5-dihydro-1,3,4-thiadiazole (8) and bis[thiosemicarbazonato]zinc(II) complex (9) was confirmed by infrared spectrum, nuclear magnetic resonance spectrum and mass spectrometry method.

Zinc and Trimethylsilyl Chloride Mediated Synthesis of 2,3,5-Trisubstituted Pyrrole Diesters from Nitriles and Ethyl Bromoacetate

An efficient, zinc-mediated, single-pot and CN+3C type pseudo-four-component synthesis of 2,3,5-trisubstituted pyrrole diesters was achieved from readily available aromatic/benzylic/aliphatic nitriles and ethyl bromoacetate under trimethylsilyl chloride catalysis.