New Semisynthetic Penicillins Obtained by Coupling of the 6-Aminopenicillanic Acid with 5-Mercapto-1,2,4-triazoles-3,4-disubstituted

In a basic medium, 5-Mercapto-1,2,4-triazoles pass into the thiol form, allowing their transformation into sodium salts, which, in reaction with sodium monochloroacetate, lead to sodium 5-thioacetates of 1,2,4-triazoles-3,4-disubstituted. Sulfur derivatives converted to pivalic mixed anhydrides were used as active forms in the acylation of 6-amino penicillanic acid (6-AP) to obtain new semisynthetic penicillins. They contain in the molecule, together with the β-lactam ring, the nucleus 3-[(5-nitroindazol-1'-yl-methyl)]-4-aryl-5-mercapto-1,2,4-triazole, both contributing to an important antibacterial effect. The structure of the new antibiotics was confirmed by the results of elemental and spectral analysis (FT-IR, ¹H- and ¹³C-NMR). The synthetic penicillins were tested for toxicological action and antibacterial activity and the obtained results were close to those for amoxicillin, the reference drug.

Optimized Synthesis of New Thiosemicarbazide Derivatives with Tuberculostatic Activity

Original results are presented in the field of research that addresses the extension of the reaction of residue of acyl-thiosemicarbazide fixation on the structure of 5-nitrobenzimidazole by a sulphonic group. The aim of the study is the increase of new thiosemicarbazide derivatives’ applicative potential in the field of biochemistry, with a wide range of medical applications. The newly obtained compounds were characterized by using elemental analysis and spectral analysis (FT-IR and ¹H NMR). A study regarding the optimization of the chemical reactions was made. The performed in vitro biological tests confirmed the tuberculostatic activity of three newly obtained compounds against Mycobacterium tuberculosis.

Immobilization and Release Studies of Triazole Derivatives from Grafted Copolymer Based on Gellan-Carrying Betaine Units

New polymer-bioactive compound systems were obtained by immobilization of triazole derivatives onto grafted copolymers and grafted copolymers carrying betaine units based on gellan and N-vinylimidazole. For preparation of bioactive compound, two new types of heterocyclic thio-derivatives with different substituents were combined in a single molecule to increase the selectivity of the biological action. The 5-aryl-amino-1,3,4 thiadiazole and 5-mercapto-1,2,4-triazole derivatives, each containing 2-mercapto-benzoxazole nucleus, were prepared by an intramolecular cyclization of thiosemicarbazides-1,4 disubstituted in acidic and basic medium. The structures of the new bioactive compounds were confirmed by elemental and spectral analysis (FT-IR and 1H-NMR). The antimicrobial activity of 1,3,4 thiadiazoles and 1,2,4 triazoles was tested on gram-positive and gram-negative bacteria. The triazole compound was chosen to be immobilized onto polymeric particles by adsorption. The Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherm were used to describe the adsorption equilibrium. Also, the pseudo-first and pseudo-second models were used to elucidate the adsorption mechanism of triazole onto grafted copolymer based on N-vinylimidazole and gellan (PG copolymer) and grafted copolymers carrying betaine units (PGB1 copolymer). In vitro release studies have shown that the release mechanism of triazole from PG and PGB1 copolymers is characteristic of an anomalous transport mechanism.

Optimized Synthesis of New N-Mustards Based on 2-Mercaptobenzoxazole Derivatives with Antitumor Activity

New di-(β-chloroethyl)-amides of some acids derived from 2-mercaptobenzoxazole were prepared by reaction of the corresponding pivalic mixed anhydrides with di-(β-chloroethyl)-amine. A study regarding the optimization of the chemical reactions was made for the case of di-(β-chloroethyl)-amines. The quantum chemical analysis by Spartan'14 was made in order to establish the most stable configuration of the ground electronic states for the obtained chemical structures and some physico-chemical parameters of N-mustards reported in this paper. Mercaptobenzoxazoles substituted in the side chain with the cytotoxic group show antitumor activity and they inhibit Ehrlich Ascites in an appreciable proportion compared to the drug I.O.B.-82, as our studies evidenced.

New Grafted Copolymers Carrying Betaine Units Based on Gellan and N-Vinylimidazole as Precursors for Design of Drug Delivery Systems

New grafted copolymers possessing structural units of 1-vinyl-3-(1-carboxymethyl) imidazolium betaine were obtained by graft copolymerization of N-vinylimidazole onto gellan gum followed by the polymer-analogous reactions on grafted polymer with the highest grafting percentage using sodium chloroacetate as the betainization agent. The grafted copolymers were prepared using ammonium persulfate/N,N,N',N' tetramethylethylenediamine in a nitrogen atmosphere. The grafting reaction conditions were optimized by changing one of the following reaction parameters: initiator concentration, monomer concentration, polymer concentration, reaction time or temperature, while the other parameters remained constant. The highest grafting yield was obtained under the following reaction conditions: ci = 0.08 mol/L, cm = 0.8 mol/L, cp = 8 g/L, tr = 4 h and T = 50 °C. The kinetics of the graft copolymerization of N-vinylimidazole onto gellan was discussed and a suitable reaction mechanism was proposed. The evidence of the grafting reaction was confirmed through FTIR spectroscopy, X-ray diffraction, 1H-NMR spectroscopy and scanning electron microscopy. The grafted copolymer with betaine structure was obtained by a nucleophilic substitution reaction where the betainization agent was sodium chloroacetate. Preliminary results prove the ability of the grafted copolymers to bind amphoteric drugs (cefotaxime) and, therefore, the possibility of developing the new sustained drug release systems.

Derivatives of 1,2,4-Triazole-3,4-Disubstituted Based on Aminoacids with Potential Biological Activity

In order to obtain new substances with potential biological activity dipeptide derivatives from p-aminobenzoyl-phenylglycine and p-aminobenzoyl-phenylalanine were grafted on 1,2,4-triazolic heterocycle. The new synthesized compounds belong to the group of antimetabolites, group used in medicine for treating malignant tumors. Also, it is possible to study the correlation between chemical structure and biological activity of the new compounds.

Synthesis and Spectral Analysis of New Antitumor Compounds with Benzimidazole Structure

Amidic compounds, derivatives of the 5-nitro-benzimidazolyl-2-mercapto-acetic acid were obtained in order to get new cytostatic substances. Two azotyperitic derivatives were obtained by the grafting of the di-(b-chloroethyl)-amine group on molecules of two of the amidic compounds. The NMR and FT-IR spectra confirmed the structure of the new compounds. The mitodepresive action of the new compounds has been tested on root meristems of Lepidiumm sativum L.

Synthesis of New Methionine Derivatives for the Treatment of Paracetamol - Induced Hepatic Injury

The direct pharmacological properties of amino acids and the possibility of using them as carriers for other active pharmacological substances are well known. Methionine, being able to yield the methyl group, is very important in the treatment of hepatic diseases. Paracetamol acute poisoning causes liver injury in both humans and animals. The study is designed to synthesize some new methionine derivatives and to<br />establish a possible correlation between the new structure and the pharmacological properties. To this end, acute experimental poisoning with Panadol® (paracetamol) was performed while, for the treatment of liver injury caused by this compound, two original synthesis derivatives of methionine, namely N-(m-nitrobenzoyl)- L-methionine and N-(m-aminobenzoyl)-L-methionine, were used. Male Wistar rats were administered<br />Panadol® (paracetamol) per oral (7500 mg/kg). N-(m-nitrobenzoyl)-L-methionine (m-NBM) 50 mg/kg and<br />N-(m-aminobenzoyl)-L-methionine (m-ABM) 50 mg/kg were given intraperitoneally, 30 minutes after Panadol® administration. Biochemical parameters such as SGOT, SGPT, serum bilirubin and glycemia were estimated to assess the liver function. Panadol® (paracetamol) poisoning produced an increase in serum transaminases, bilirubin and glicemia. These effects were reduced by treatment with m-NBM and especially m-ABM. These biochemical observations were supplemented by histopathological examination of liver sections. The results obtained with m-ABM were comparable with those reported on methionine, which is a recognised antidote in paracetamol poisoning.

Catalase Immobilized on Poly(Acrylic Acid-co-Vinyl Alcohol)

The paper studies the reaction of catalase’s immobilization on a synthetic polymer (copolymer of the acrylic acid with vinyl alcohol), through amidation of enzyme’s terminal amine groups with the lateral<br />carboxylic group of the macromolecular support, as activated by dicycloxexyl carbodiimide. The support, possessing the properties of a hydrogel, has been synthesized through copolymerization of the acrylic acid with vinyl acetate, followed by hydrolysis of the acetate groups to the hydroxylic groups. The influence of some reaction parameters (such as the activator/support and enzyme/support ratios, duration) on the efficiency of the enzyme’s coupling was studied. The coupling reactions were realized conformely to a centered, rotator, composed, second order experimental program, which permitted the establishment of the conditions necessary for obtaining a coupling product containing the highest amount of immobilized enzyme. Kinetic study of the reaction catalyzed by the coupling products has indirectly evidenced enzyme’s immobilization to the macromolecular support, and also, a sufficiently high catalytic activity of the enzymatic preparation obtained.

Antitumoral Activity Induced by Alkylating Agents Conjugated to Poly(maleic anhydride-alt-vinyl acetate)

New polyanionic polymer conjugates with antitumoral activity are synthesized by chemically binding mustard type alkylating derivatives of di-(β-chloroethyl)-amine and tri-(β-chloroethyl)-amine, respectively, onto poly(maleic anhydride-alt-vinyl acetate). The structures of the compounds are verified by FTIR, 1H NMR, and elemental analysis. The antitumoral activity of these polymeric drugs is evaluated in vivo using carcinosarcoma Walker 256 solid tumors in Wister rats. The conjugates exhibit antitumor regression (ATR) values between 25 and 44% depending on comonomers' structure. In addition, an accumulation in the solid tumors (enhanced permeability and retention (EPR) effect) by these compounds is observed. These compounds also cause small organotropic effects, such as increases in the liver, spleen, and kidney weight.

Aminoacids Derivatives with a Potential Anti-inflammatory Activity

The paper presents the synthesis of benzimidazole derivatives starting from asparagic acid. The reaction products were analysed from physical and chemical point of view and their biological activity (acute toxicity, anti-inflammatory activity and gastric tolerance) was evaluated. The product association with acetylsalicylic acid (Aspirin) improves its anti-inflammatory activity (higher with 38%). For acetylsalicylic acid dosing, in mixtures with benzimidazole derivatives, a new HPLC method has been proposed. The method is reproducible, selective and easy to manipulate. The derivatives based on benzimidazole and asparagic acid and their associates with acetylsalicylic acid present good anti-inflammatory properties.

New Perspectives in Therapy of Intoxications by Organophosphoric Compounds

Little references actually exist on neutralization therapy which could constitute the missing ring from an efficient treatment. As structural model capable to interact with organophosphoric substances, at the level of phosphor (P) atom, the common chemical element of the hole class of substances, was proposed those of benzimidazole. Different quantities of benzimidazole were put in contact with a fix quantity of trichlorphon in acid conditions and formation of a new compound was evidentiated by infrared spectrometry. Similar experiments were made utilizing benzimidazole derivatives (2 methyl or 2 benzyl benzimidazole) and different temperatures: 35°C and 40°C. By increasing massic rate: benzimidazole/triclorfon as well an increased reaction temperature, have favourably influenced trichlorphon capture. The obtained results justified an continuation of researches in the direction of new compounds with a structure similar with that of benzimidazole for funding an efficient neutralization therapy for organophosphoric substances.

Synthesis and biological activity of some new 1,3,4-thiadiazole and 1,2,4-triazole compounds containing a phenylalanine moiety

New 1,3,4-thiadiazole, 6, 7 and 1,2,4-triazole derivatives, 8, 9 containing a phenylalanine moiety have been synthesized by intramolecular cyclization of 1,4-disubstituted thiosemicarbazides, 4, 5, in acid and alkaline media, respectively; the thiosemicarbazides were obtained by reaction of hydrazide 3 with appropriate aromatic isothiocyanates. The toxicity of the synthesized compounds was evaluated and the anti-inflammatory study of the triazole compound 9 established an appreciable anti-inflammatory activity that is comparable with that of other nonsteroidal anti-inflammatory agents.

New di-(beta-chloroethyl)-alpha-amides on N-(meta-acylamino-benzoyl)- D,L-aminoacid supports with antitumoral activity

In order to obtain new compounds with antitumoural action the N-(meta-acylaminobenzoyl)-alpha-acylaminobenzoyl)-alpha-aminoacids 4-9 were prepared. These compounds were subsequently converted into the corresponding Delta(2)-oxazolin-5-ones 10-15, which in turn were submitted to a ring opening reaction with di-(beta-chloroethyl)amine to afford the peptide supported N-mustards 16-21, which showed low toxicity and cytostatic activity similar to that of sarcolisine against the Ehrlich ascite and Walker 253 carcinosarcoma.

[Synthesis and antimicrobial activity of some new (sulfon-amidophenyl)-amide derivatives of N-(m-nitrobenzoyl)-D,L-methionine]

In order to obtain new compounds with potential antimicrobial activity some new (sulfon-amidophenyl)-amide derivatives of N-(m-nitrobenzoil)-D,L-methionine have been synthesized. The compounds have been obtained by decyclization reaction of 2-(m-nitrophenyl)-4-(beta-P-methylthioethyl)- delta2-5-oxazolinone with various sulfonamides. The chemical structure of the new sulfonamides was confirmed by elemental analysis data and IR and 1NMR spectral measurements. The compounds were also investigated for their antimicrobial activity using Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Proteus vulgaris strains.

Synthesis and antimicrobial activity of some new 1,3,4-thiadiazole and 1,2,4-triazole compounds having a D,L-methionine moiety

New 1,3,4-thiadiazole, 5a-e, and 1,2,4-triazolecompounds 6a-c, containing a D,L-methionine moiety were synthesized by intramolecular cyclization of 1,4-disubstituted thiosemicarbazides 4a-e in acid and alkaline media, respectively. The potential antimicrobial effects of the synthesized compounds were investigated using the Staphylococcus aureus ATCC 25923, Bacillus antracis ATCC 8705, Bacillus cereus ATCC 10987, Sarcina lutea ATCC 9341 and Escherichia coli ATCC 25922 strains. The newly synthesized compounds exhibited promising activities against Bacillus antracis and Bacillus cereus.

[Synthesis and toxicity of some new (sulfon-amidophenyl)-amide derivatives of N-(m-nitrobenzoil)-D,L-asparagine]

In order to obtain new compounds with potential antibacterial activity some new (sulfonamidophenyl)-amide derivatives of N-(m-nitrobenzoil)-D,L-asparagine have been synthesized. The compounds have been obtained by decyclization reaction of 2-(m-nitrophenyl)-4-(beta-amidomethyl)-delta2-oxazolinone with various sulfonamides. A toxicity study with determination of DL50 value has also been realized.

Spiro[4.5]deca-2,7-diene-1,6-dione and Spiro[5.5]undeca-2,8-diene-1,7-dione. Synthesis, Reductions and Palladium-Catalyzed Allylic Substitutions

Spiro[4,5]deca-2,7-diene-1,6-dione (2a) and spiro[5,5]undeca-2,8-diene-1,7-dione (2b) were prepared by a direct synthesis starting from diethyl malonate. The two-step 1,2-reductions (NaBH4/CeCl3) of the diones gave cis/trans-diols, which could be easily transformed into diacetates. Both diacetates were subjected to Pd(0)-catalyzed allylic alkylations, in which the relative stereochemistry was retained.

New derivatives of m-nitrobenzoyl-asparagic acid and m-nitrobenzoyl-asparagine with anti-inflammatory action

In order to obtain new biologically active compounds some derivatives of 1-[N-(m-nitrobenzoyl)-alpha-D,L-asparaginyl]-2-benzyl-benzimidazole have been synthesized by ring opening reactions of 2-(m-nitrophenyl)-4-(beta-amidomethyl)-delta 2-oxazolin-5-one and 2-(m-nitrophenyl)-4-(beta-carboxymethyl)-delta 2-oxazolin-5-one with 2-benzylbenzimidazole (dibazole).

[Hydrazide derivatives with biologically active 1,2,4-triazole support]

This study presents the synthesis of ten new hydrazides with 1,2,4-triazole support. The structures of the obtained compounds were elucidates by means of the elemental analysis data as well as by IR spectral measurements. The antimicrobial and antifungal actions of this derivates are also tested. The results show that the compounds with the functional group 4-chlore-2-methoxyphenyle are more active.

Derivatives of asparagic acid with hypotensive action

To obtain new compounds with biological activity, 1-[N-(p-nitrobenzoyl)-alpha-D,L- asparagyl]-benzimidazole derivatives were synthesized by decyclization of 2-(p-nitrophenyl)-4-[2'- (diethylamino) ethyl-carboxymethyl]-delta 2-oxazolinone-5 with benzimidazole, 2-methylbenzimidazole and 5,6-dimethyl-benzimidazole. The synthesized products show a hypotensive action comparable to that Hipopresol.

On hypotensive action of some imidazoline derivatives of sulphonamidated aryloxyalkylcarboxylic acids

New imidazolines derived from sulphonamidated aryloxyalkylcarboxylic acids have been tested for their antihypertensive action and toxicity. The obtained results attest a remarkable biological action, low toxicity and a good absorption in oral administration.