Design and synthesis of novel 1,3,4-thiadiazole thioglycosides as promising antimicrobial potent structures

Thiosemicarbazide was used as a key starting material for the building of a diversity of novel heterocyclic moieties. The heterocyclization reaction of thiosemicarbazide derivatives with carbon disulfide in basic conditions afforded novel heterocyclic 1,3,4-thiadiazolethiolate derivatives. 1,3,4-thiadiazole-2-thiol was successfully reacted with protected α-D-gluco- and galacto-pyranosyl bromides in dimethylformamide at room temperature to give the matching 1,3,4-thiadiazole S-glycosides in good yields. The latter compounds were reacted with ammonia-methanol at room temperature for 10 min, and the deprotected derivatives were obtained in good yields. The newly synthesized compounds were characterized by basic analyses and spectral information (IR,1H NMR, and 13C NMR, X-ray). All newly produced compounds were evaluated and screened for their antibacterial activities. Compound 6f proved to be the most active antimicrobial among the investigated heterocycles.

Naphthyl cyanoketene N,S-acetals in glycoside synthesis: a new preparative route to a new class of N-naphthylcyanoacrylamide thioglycosides and their conversions to naphthyl-pyrazole hybrids

The novel N-naphthylcyanoacrylamide thioglycosides 4 were readily prepared by the reaction of N-napthylcyanoacetamide 1 with aryl isothiocyanates in the presence of potassium hydroxide, followed by coupling of the produced salts 2 with 2,3,4,6-tetra-O-acetyl-α-d-gluco- and galacto-pyranosyl bromides 3. The N-naphthyl acrylamide thioglycoside 12 was prepared by the reaction of N-napthylcyanoacetamide 1 with glucose isothiocyante 10 in the presence of potassium hydroxide, followed by alkylation of the produced salt 11 with methyl iodide. The reaction of thioglycoside compounds 4 with hydrazines afforded the corresponding naphthyl-pyrazole hybrids.

Synthesis of novel pyridine and pyrimidine thioglycoside phosphoramidates for the treatment of COVID-19 and influenza A viruses

A novel series of pyridine, cytosine, and uracil thioglycoside analogs (4a-i, 9a,b, and 13a,b, respectively) and their corresponding phosphoramidates (6a-I, 10a,b, and 14a,b, respectively) were synthesized and assessed for their antiviral inhibitory activities in a dual-pathogen screening protocol against SARS-CoV-2 and influenza A virus (IAV). MTT cytotoxicity (TC50) and plaque reduction assays were used to explore inhibition and cytotoxicity percentage values for H5N1 influenza virus strain and the half-maximal cytotoxic concentration (CC₅₀) and inhibitory concentration (IC₅₀) for SARS-CoV-2 virus. Most of the tested compounds demonstrated dose-dependent inhibition behavior. Both cytosine thioglycoside phosphoramidates 10a and 10b exhibited the most potent profiles with 83% and 86% inhibition at 0.25 µM concentration against H5N1 and IC₅₀ values of 12.16 µM, 14.9 µM against SARS-CoV-2, respectively. Moreover, compounds 10a and 10b have been shown to have the highest selectivity index (SI) among all the tested compounds against SARS-CoV-2 with 28.2 and 26.9 values, respectively.

Anti-Covid-19 Drug Analogues: Synthesis of Novel Pyrimidine Thioglycosides as Antiviral Agents Against SARS-COV-2 and Avian Influenza H5N1 Viruses

A class of pyrimidine thioglycoside analogs (6a-h) were synthesized from a reaction of 2-cyano-3,3-dimercapto-N-arylacrylamide (2a-d) and thiourea to produce the corresponding 4-amino-2-mercapto-N-arylpyrimidine-5-carboxamide derivatives (3a-d), and stirring of compounds (3a-d) with peracylated α-d-gluco- and galacto-pyranosyl bromides (4a,b) in DMF-sodium hydride gave the corresponding pyrimidine thioglycosides (5a-h). Deacetylation of the pyrimidine thioglycosides via a reaction with dry NH₃/MeOH gave the corresponding free pyrimidine thioglycosides (6a-h). The compounds have been characterized by ¹³C NMR, ¹H NMR, and IR. Pharmacological evaluation of compounds 3a-d, 5a-h, and 6a-h in vitro against SARS-COV-2 and Avian Influenza H5N1 virus strains revealed that some compounds possess interesting activity.

Synthesis of novel pyrimidine thioglycosides as structural analogs of favipiravir (avigan) and their antibird flu virus activity

Novel class of amino pyrimidine thioglycoside derivatives were designed from sodium 2-cyano-3-(arylamino)prop-1-ene-1,1-bis(thiolate) 1a-d and guanidine hydrochloride 2 to afford the corresponding sodium 2,6-diamino-5-aryl-1,2-dihydropyrimidine-4-thiolate 3a-d, which in coupling with peracylated α-D-gluco- and galactopyranosyl bromides 5a,b in DMF gave the corresponding pyrimidine thioglycosides 6a-h. Acidification of 2,6-diamino-5-aryl-1,2-dihydropyrimidine-4-thiolate salts 3a-d with hydrochloric acid formed the corresponding pyrimidine-4-thioles 4a-d. The latter were stirred with peracetylated halo sugars α-D-gluco- and galacto-pyranosyl bromides in sodium hydride and DMF to yield the pyrimidine thioglycosides 6a-h. Deacetylation of the pyrimidine thioglycosides gave the corresponding free pyrimidine thioglycosides 7a-h. The compounds were characterized by ¹³C NMR, ¹H NMR, and IR. The pyrimidine thioglycosides 6a-h and free pyrimidine thioglycosides 7a-h were tested against H5N1 virus strain and exhibited high to moderate activity.

Toward Developing Therapies against Corona Virus: Synthesis and Anti-Avian Influenza Virus Activity of Novel Cytosine Thioglycoside Analogues

A series of pyrimidine and pyrimidine thioglycoside derivatives were newly synthesized using sodium 2-cyano-3-(arylamino)prop-1-ene-1,1-bis(thiolates) and urea to give the corresponding sodium 6-amino-5-aryl-2-oxo-1,2-dihydropyrimidine-4-thiolates. Stirring of the latter with peracetylated α-d-gluco- and galacto-pyranosyl bromides in DMF afforded the corresponding pyrimidine thioglycosides. On the other hand, treatment of 6-amino-5-aryl-2-oxo-1,2-dihydropyrimidine-4-thiolate salts with hydrochloric acid produced the corresponding pyrimidine-4-thioles, which on stirring with α-d-gluco- and galacto-pyranosyl bromides in sodium hydride and DMF gave the corresponding pyrimidine thioglycosides. Deacetylation of the protected pyrimidine thioglycosides gave the corresponding free pyrimidine thioglycosides. The synthesized compounds have been characterized by ¹³C NMR, ¹H NMR, and IR spectroscopy. The pyrimidine thioglycosides and free pyrimidine thioglycosides were tested against avian influenza H5N1 virus strain and exhibited highest to moderate activity.

Novel Synthesis and Biological Evaluation of the First Pyrazole Thioglycosides as Pyrazofurin Analogues

This study reports a novel and efficient method for the synthesis of the first reported novel class of pyrazole thioglycosides 6a-h. These series of compounds were designed through the reaction of sodium 2-cyano-3-oxo-3-(4-substitutedphenylamino)prop-1-ene-1,1-bis(thiolate) salts 2 with hydrazine hydrate in ethanol at room temperature to give the corresponding sodium 5-amino-4-(substitutedphenylcarbamoyl)-1H-pyrazole-3-thiolates 3a-d. The latter compounds were treated with protected α-D-gluco- and galacto-pyranosyl bromides 4a,b in DMF at ambient temperature to give in a high yields the corresponding pyrazole thioglycosides 6a-h. Treatment of pyrazole salts 3a-d with hydrochloric acid at amobient temperature afforded the corresponding 3-mercaptopyrazole derivatives 5. The latter compounds were treated with peracetylated sugars 4 in sodium hydride in ethanol at ambient temperature to tolerate the S-glycosyl 6a-h compounds. Ammonolysis of the pyrazole thioglycosides 6a-h afforded the corresponding free thioglycosides 7a-h. The toxicity and antitumor activities of the synthesized compounds were studied.