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.

Crystal structure of potassium [4-amino-5-(benzo[d]thia-zol-2-yl)-6-(methyl-sulfan-yl)pyrimidin-2-yl](phenyl-sulfon-yl)aza-nide di-methyl-formamide monosolvate hemihydrate

The title compound, K+·C18H14N5O2S3 -·C3H7NO·0.5H2O, was obtained in a reaction designed to deliver a neutral 2-pyrimidylbenzo-thia-zole. The anion is deprotonated at the sulfonamide nitro-gen. The asymmetric unit of the title compound contains two potassium cations, two anions, two mol-ecules of DMF and one of water. The anions display some conformational differences but each contains an intra-molecular N-H⋯Nbenzo-thia-zole hydrogen bond. The potassium ions both display a highly irregular six-coordination, different for each potassium ion. The anions, together with the DMF and water mol-ecules, are linked by four classical hydrogen bonds to form chains parallel to the b-axis direction.

The Reaction of Dimethyl N-cyanodithioiminocarbonate with Amino- and Oxo-azoles: A New General Synthesis of Methylsulfanylazoloazines

A novel and efficient method for the synthesis of a new variety of methylsulfanylazoloazines by the reaction of dimethyl N-cyanodithioiminocarbonate with diazoles containing amino and active methylene functions. The synthetic potential of the method is demonstrated.

New synthetic strategies for acyclic and cyclic pyrimidinethione nucleosides and their analogues

Pyrimidinethione nucleosides are effective compounds and have significant and pivotal effects in several fields. New synthetic strategies for many pyrimidinethione nucleosides including acyclic and cyclic derivatives have been reported.

Novel synthesis of new pyrazole thioglycosides as pyrazomycin analogues

This study reports a novel method for the synthesis of a new class of pyrazole thioglycosides 7a-h as pyrazomycin analogues. 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 phenyl hydrazine in ethanol at room temperature to give the corresponding sodium 5-amino-4-(substitutedphenylcarbamoyl)-1-phenyl-1H-pyrazole-3-thiolates 3a-d. The latter compounds were treated with tetra-acetylated glycosyl bromides 4a,b in DMF at ambient temperature to give the corresponding pyrazole thioglycosides 6a-h. Treatment of pyrazole salts 3a-d with hydrochloric acid at room temperature afforded the corresponding 3-mercaptopyrazole derivatives 5. The latter compounds were treated with tetra-acetylated glycosyl bromides 4 in sodium hydride-DMF to tolerate the S-glycosyl 6a-h compounds. Ammonolysis of the latters afforded the corresponding free thioglycosides 7a-h. The structures of the reaction products were elucidated based on spectral data and elemental analysis.

Design, synthesis, docking, and antimicrobial evaluation of some novel pyrazolo[1,5-a] pyrimidines and their corresponding cycloalkane ring-fused derivatives as purine analogs

Background

Over the years, pyrazolopyrimidine derivatives have been recognized as having antimicrobial activities. Recently, we reported different synthetic methods to prepare pyrazolopyrimidine derivatives as anticancer and antimicrobial agents. The studies showed that our previously reported 5-aminopyrazoles 2 act as a building block for the preparation of a variety of interesting pyrazolopyrimidines as purine analogs.

Purpose

The objective of this study was to describe the direct new method for preparation of novel pyrazolo[1,5-a]pyrimidine derivatives and their corresponding cycloalkane ring-fused derivatives. Also, the new compounds were tested in vitro for their antibacterial and antifungal activity properties.

Methods

Pyrazolo[1,5-a]pyrimidine derivatives were prepared by the reaction of our previously reported 5-aminopyrazoles 2 with suitable sodium salts of (hydroxymethylene) cycloalkanones and sodium salts of unsaturated ketones.

Results

The structures of the new compounds were characterized according to their mass spectroscopy, 1H NMR, IR and elemental analyses. Compounds 8b, 10e, 10i, and 10n were the most active compounds against Gram-positive and Gram-negative bacterial species. Compound 10i with two moieties of 4-Br-C6H4 revealed increased reactivity compared with ampicillin as standard reference.

Conclusion

About twenty two novel pyrazolo[1,5-a]pyrimidine derivatives and their corresponding cycloalkane ring-fused derivatives were prepared through the reaction of 5-aminopyrazoles 2 with different sodium salts of (hydroxymethylene) cycloalkanones and sodium salts of unsaturated ketones. The antibacterial and antifungal activities of the newly synthesized compounds were evaluated and revealed that compounds 8b, 10e, 10i, and 10n were the most active compounds against Gram-positive and Gram-negative bacterial strains.

Crystal structure of racemic 2-[(β-arabino-pyran-osyl)-sulfanyl]-4,6-diphenylpyridine-3-carbo-nitrile

In the racemic title compound, C23H20N2O4S, the sulfur atom is attached equatorially to the sugar ring with unequal S-C bonds, viz.: S-Cs = 1.808 (2) and S-Cp = 1.770 (2) Å (s = sugar, p = pyrid-yl). The dihedral angles between the pyridine ring and its attached phenyl groups are 42.24 (8) and 6.37 (14)°. In the crystal, a system of classical O-H⋯O and O-H⋯(O,O) hydrogen bonds links the mol-ecules to form tube-like assemblies propagating parallel to the c-axis direction. Weak C-H⋯N inter-actions are also observed.

Novel dihydropyridine thioglycosides and their corresponding dehydrogenated forms as potent anti-hepatocellular carcinoma agents

A novel method for preparation of a new class of dihydropyridine thioglycosides and their corresponding dehydrogenated forms, via reaction of piperidinium salts of dihydropyridinethiones with 2,3,4,6-tetra-O-acetyl-α-D-gluco- and galactopyranosyl bromides has been studied. The evaluation of antiproliferative activity against HepG-2 cell lines (liver carcinoma cell lines) of the dihydropyridine thioglycosides and pyridine thioglycosides revealed that many of the thioglycosides have interesting antitumor activities specifically 5c, 5g, 5l, 5o, 5p, 7a, 7i, 7p, 8b, 8f, 8s, and 8v.

Design, synthesis, molecular docking and anti-hepatocellular carcinoma evaluation of novel acyclic pyridine thioglycosides

A novel series of acyclic pyridine thioglycosides has been synthesized. Evaluation of the anti proliferative activity of these compounds against HEPG-2 cell lines (liver carcinoma cell lines) shows that most of the compounds have high anti-tumor activities especially 6b, 6c, 7b and 7c. Furthermore, in the modeling study, these compounds showed that they have high binding affinity with thymidylate synthase dihydrofolate reductase (TS-DHFR).

First novel synthesis of triazole thioglycosides as ribavirin analogues

This study reports a novel and efficient method for the synthesis of the first reported novel class of triazole thioglycosides. These series of compounds were designed through the reaction of potassium cyanocarbonimidodithioate 2 with hydrazine derivatives 3a-d in EtOH at room temperature to give the corresponding potassium 5-amino-1H-1,2,4-triazole-3-thiolates 4a-d. The latter compounds were treated with tetra-O-acetyl-α-D-glucopyranosyl bromide 6a and tetra-O-acetyl-α-D-galactopyranosyl bromide 6b in DMF at room temperature to give in high yields the corresponding triazole thioglycosides 7a-h. Treatment of triazole salts 4a-d with hydrochloric acid afforded the corresponding 3-mercaptotriazoles 5a-d. Compounds 5a-d were then reacted with bromoperacetylated sugars 6a,b in sodium hydride-DMF at ambient temperature to afford the thioglycosyl compounds 7a-h. Ammonolysis of the triazole thioglycosides 7a-h afforded the corresponding free thioglycosides 8a-h. The scope and limitation of the method is demonstrated. The structure of the reaction products was confirmed on the basis of their elemental analysis and spectral data (IR, ¹H NMR, MS and ¹³C NMR).

A facile synthesis of novel pyrazolopyrimidine thioglycosides as purine thioglycoside analogues

The easy, convenient and high yielding preparation of new thioglycosides incorporating mercaptopyrazolo[1,5-a]pyrimidine moieties from readily accessible starting materials has been reported. The main step of this protocol is the formation of 7-mercaptopyrazolo[1,5-a]pyrimidine-6-carbonitrile derivatives 4a-d by condensation of sodium 2-cyano-3-ethoxy-3-oxoprop-1-ene-1,1-bis(thiolate) 1 with 4-(aryldiazenyl)-1H-pyrazole-3,5-diamines 3a-d to form target compounds 4a-d, which coupled with tetra-O-acetyl-α-D-glycopyranosyl bromides 5a,b in the presence of basic medium to provide the corresponding product purine thioglycoside analogs 6a-h. Ammonolysis of the latter compounds 6a-d at ambient temperature for 10 minutes, led to the free glycoside derivatives 7a-h, which were obtained in approximately quantitative yields. Their structures were created based on the spectroscopic and elemental data.

Synthesis of the first novel pyrazole thioglycosides as deaza ribavirin analogues

This study reports a novel and efficient method for the synthesis of the first reported novel class of thiopyrazoles and their corresponding thioglycosides. These series of compounds were designed through the reaction of hydrazine derivatives with sodium dithiolate salt 2 in EtOH at ambient temperature to give the corresponding sodium 5-amino-4-cyano-1H-pyrazole-3-thiolates 4a-d. The latter compounds were treated with α-acetobromoglucose 6a and α-acetobromogalactose 6b in DMF at ambient temperature to give in an excellent yields the corresponding pyrazole S-glycosides 7a-h. Ammonolysis of the pyrazole thioglycosides 7a-h afforded the corresponding free thioglycosides 8a-h.

Crystal structure of N-[6-amino-5-(benzo[d]thia-zol-2-yl)-3-cyano-4-methyl-sulfanyl-2-oxo-1,2-di-hydro-pyridin-1-yl]-4-methyl-benzene-sulfonamide di-methyl-formamide monosolvate

In the title compound, C21H17N5O3S3·C3H7NO, the toluene-sulfonamide ring and the combined ring system involving the pyridone and benzo-thia-zole rings subtend an inter-planar angle of 39.86 (4)°. The pyridone and benzo-thiazyl rings are linked by the intra-molecular hydrogen bond N-Hamine⋯Nthia-zole. The DMF O atom accepts two classical hydrogen bonds. The mol-ecules are linked by hydrogen bonds and an S⋯O contact to form layers parallel to the bc plane.

Crystal structure of 4,6-dimethyl-2-{[3,4,5-trihy-droxy-6-(hy-droxy-meth-yl)tetra-hydro-2H-pyran-2-yl]sulfan-yl}nicotino-nitrile

In the title compound, C14H18N2O5S, the C-S bond lengths are unequal, with S-Cglucose = 1.8016 (15) Å and S-Cpyrid-yl = 1.7723 (13) Å. The hydro-philic glucose residues lie in the regions z ≃ 0.25 and 0.75. Four classical hydrogen bonds link the mol-ecules to form layers parallel to the ab plane, from which the pyridyl rings project; pyridyl ring stacking parallel to the a axis links adjacent layers.

Heterocyclic thioglycosides in carbohydrate research: Synthesis of thiophene thioglycosides

A novel synthesis of thiophene thioglycosides is carried out via a one-pot reaction of sodium thiophenethiolates with α-halogeno sugars. The sodium thiophenethiolate salts were prepared using sodium cyanoethylene thiolate salts. The structures of the reaction products were established on the basis of their elemental analysis and spectral data (IR, ¹H NMR, MS, and ¹³C NMR).

Crystal structure of N'-[2-(benzo[d]thia-zol-2-yl)acet-yl]-4-methyl-benzene-sulfono-hydrazide

In the title compound, the hydrazide N atom bonded to the C=O group is planar, whereas that bonded to the SO₂ group is pyramidally coordinated. The inter­planar angle between the ring systems is 40.71 (3)°. In the crystal, mol­ecules are connected by N—H⋯O=C and N—H⋯N_thia­zole hydrogen bonds, forming ribbons parallel to the b axis.

In the title compound, C₁₆H₁₅N₃O₃S₂, the hydrazide N atom bonded to the C=O group is planar, whereas that bonded to the SO₂ group is pyramidally coordinated. The inter­planar angle between the ring systems is 40.71 (3)°. Mol­ecules are connected into ribbons parallel to the b axis by two classical hydrogen bonds N—H⋯O=C and N—H⋯N_thia­zole.

Crystal structure of 2-cyano-3,3-bis-(ethyl-sulfan-yl)-N-o-tolyl-acryl-amide

In the mol-ecule of the title compound, C₁₅H₁₈N₂OS₂, the central S₂C=C(CN)C moiety is planar (r.m.s. deviation = 0.029 Å). The C=O and C-CN groups are trans to each other across their common C-C bond. In the crystal, one classical and two 'weak' hydrogen bonds combine with borderline N⋯N and S⋯S contacts to form layers parallel to (10-2). One ethyl group is disordered over two positions with relative occupancy 0.721/0.279 (7).

Antimetabolites: Design, synthesis, and cytotoxic evaluation of novel dihydropyridine thioglycosides and pyridine thioglycosides

A convenient synthesis of a novel series of dihydropyridine and pyridine thioglycosides was developed. The evaluation of anti-proliferative activity against HepG-2 cell lines (liver carcinoma cell lines) shows that most of the compounds have antitumor activity, especially 5b, 5f, 5j, 5n, 7b, 7f, 7j, 7n, 8b, 8f, and 8j. The results of molecular docking reveal that these compounds have high binding affinity by hydrogen bond formation with the binding pocket of thymidylate synthase dihydrofolate reductase (TS-DHFR).

Design, synthesis, and in vitro anti-hepatocellular carcinoma of novel thymine thioglycoside analogs as new antimetabolic agents

A first reported direct method for preparation of thymine thioglycoside analogs utilizing novel pyrimidine-2(1H)-thiones and α-bromoglucose or α-bromogalactose tetraacetate as starting components is described. The synthetic potential of the method is demonstrated. The evaluation of antiproliferative activity against HepG-2 cell lines (Liver carcinoma cell lines) shows that most of the compounds have high antitumor activities especially 6b, 6e, 11b, and 12b. Moreover, molecular modelings of these compounds reveal that they have high binding affinity through hydrogen bond interaction with the binding pocket of thymidylate synthase dihydrofolate reductase (TS-DHFR).

Pyrimidine non-nucleoside analogs: A direct synthesis of a novel class of N-substituted amino and N-sulfonamide derivatives of pyrimidines

A convenient method for the regioselective synthesis of pyrimidine non-nucleoside analogs was developed. This study reports a novel and efficient method for the synthesis of a new type of N-substituted amino methylsulfanylpyrimidines and the corresponding pyrazolo[3,4-d]pyrimidines. This series of compounds was designed through the reaction of dimethyl N-cyanodithioiminocarbonate with 2-cyano-N'-(thiophen-2-yl-, furan-2-yl- and pyridin-4-ylmethylene)acetohydrazide and N'-(2-cyanoacetyl)arylsulfonohydrazides. The scope and limitation of the method are demonstrated. The antibacterial and antifungal activities of the synthesized compounds were also evaluated.

Nucleic acid components and their analogs: Design and synthesis of novel cytosine thioglycoside analogs

The synthesis of a new category of novel cytosine 4-thioglycoside analogs has been first accomplished. The main step of this strategy is the synthesis of sodium pyrimidine-4-thiolate through the condensation of 2-cyano-N-arylacetamides with sodium cyanocarbonimidodithioate, followed by coupling with α-bromo-sugars to afford the corresponding cytosine 4-thioglycoside analogs. The free thioglycosides were also prepared. Subsequent studies on the application of this strategy for the preparation of other potent pyrimidine thioglycosides are reported.

Crystal structure of 1-amino-2-oxo-2,5,6,7,8,9-hexa-hydro-1H-cyclo-hepta-[b]pyridine-3-carbo-nitrile

In the title compound, C11H13N3O, the seven-membered ring adopts a conformation such that the three atoms not involved in the aromatic plane lie on the same side of that plane. One hydrazinic H atom forms an intra-molecular hydrogen bond to the O atom; the other forms a classical inter-molecular hydrogen bond N-H⋯O, which combines with a 'weak' Har⋯O inter-action to build up double layers of mol-ecules parallel to the bc plane.