First Synthesis of N‐Substituted Amino and N‐Sulfonylaminated Methylthiopyrimidines: Reaction of Dimethyl N‐Cyanodithioiminocarbonate With Substituted Hydrazides

Medicinal Chemistry of Pyrazolopyrimidine Scaffolds Substituted with Different Heterocyclic Nuclei

BACKGROUND

Medicinal chemistry of pyrazolopyrimidine scaffolds substituted with different heterocyclic nuclei has attracted great attention due to their wide range of biological activities that have been reported. Pyrazolopyrimidine scaffold is an important privileged heterocycle nucleus in drug discovery.

METHODS

All pharmacological activities of pyrazolopyrimidine scaffold have been mentioned, such as anticancer, anti-inflammatory, antihypertensive, antitubercular, antiviral, antibacterial, antifungal, antidiabetic, and anti-obesity agents. In addition, it was used in both osteoporosis and neurological disorders. The difference in potency and bioavailability of pyrazolopyrimidine derivatives refers to the substituent groups that can increase the activity against specific targets and enhance their selectivity.

RESULTS

This review provides an overview of different synthetic pathways, structure activity relationships, and preclinical studies of pyrazolopyrimidine scaffolds substituted with a variety of heterocyclic nuclei, as well as it provides a discussion on the significant biological findings of these important scaffolds. In addition, it provides some insights on the different macromolecular targets that pyrazolopyrimidine scaffold can effectively work on, such as; cyclin dependent kinases; CDK2, CDK7, and CDK9, checkpoint kinases; CHK1 and CHK2 and their correlation with the anticancer activity, PI3Kα, transient receptor potential canonical 6, B-Raf kinase, Interleukin- 1 receptor-associated kinase 4, B-cell lymphoma 6, TRKA-C kinase, potent kDa ribosomal protein S6 kinase, colon cancer cell line (CaCo-2), domain receptor kinase (KDR), HepG-2 carcinoma cell, FLT3. The antibacterial activity against B. subtilis and E. coli and antifungal activity against C. albicans, C. tropicalis, A. niger, and A. clavatus are discussed.

CONCLUSION

This review provides an overview of the different pharmacological activities of the pyrazolopyrimidine scaffold and its correlation with chemical structure. Some exciting new developments in pyrazolopyrimidine scaffolds are also presented in this review.

A First Microwave-Assisted Synthesis of a New Class of Purine and Guanine Thioglycoside Analogs

A first microwave-assisted synthesis of a new class of novel purine thioglycoside analogs from readily available starting materials has been described. The key step of this protocol is the formation of sodium pyrazolo[1,5-a]pyrimidine-7-thiolate and 7-mercaptopyrazolo[1,5-a]pyrimidine derivatives via condensation of 5-amino-1H-pyrazoles with sodium 2,2-dicyanoethene-1,1-bis(thiolate) salts or 2-(dimercaptomethylene)malononitrile, respectively, under microwave irradiation, followed by coupling with halo sugars to give the corresponding purine thioglycoside analogs. The obtained purines and purines thioglycosides derivatives were evaluated in vitro against lung (A549), colon (HCT116), liver (HEPG2), and prostate (PC3) cancer cell lines. Some of these compounds (5b, 5d, 5f, and 9a-d) exhibited little potency toward the four cell lines. On the other hand, compound 5a elicited higher cytotoxicity on both prostate (PC3) and colon (HCT116), respectively, while it was found moderate on lung (A549), and inactive on liver (HEPG2). Moreover, compound 5c was found moderate with LC50 values 52.0-88.9 μM for almost all the cell lines.

Antimetabolites: A First Synthesis of a New Class of Cytosine Thioglycoside Analogs

A first synthesis of a new class of novel cytosine thioglycoside analogs from readily available starting materials has been described. The key step of this protocol is the formation of sodium pyrimidine-4-thiolate via condensation of N'-arylidene-2-cyanoacetohydrazides with sodium cyanocarbonimidodithioate salt, followed by coupling with halo sugars to give the corresponding cytosine thioglycoside analogs. Ammonolysis of the latter compounds afforded the free thioglycosides.

True symmetry or pseudosymmetry: 5-amino-1-(4-methylphenylsulfonyl)-4-pyrazolin-3-one and a comparison with its 1-phenylsulfonyl analogue

The title compound, C(10)H(11)N(3)O(3)S, (I), crystallizes as the NH tautomer. The two rings subtend an interplanar angle of 72.54 (4)°. An intramolecular hydrogen bond is formed from the NH(2) group to a sulfonyl O atom. The molecular packing involves layers of molecules parallel to the bc plane at x ≃ 0, 1 etc., with two classical linear hydrogen bonds (amino-sulfonyl and pyrazoline-carbonyl N-H...O) and a further interaction (amino-sulfonyl N-H...O) completing a three-centre system with the intramolecular contact. The analogous phenyl derivative, (II) [Elgemeie, Hanfy, Hopf & Jones (1998). Acta Cryst. C54, 136-138], crystallizes with essentially the same unit cell and packing pattern, but with two independent molecules that differ significantly in the orientation of the phenyl groups. The space group is P2(1)/c for (I) but P2(1) for (II), which is thus a pseudosymmetric counterpart of (I).

trans-Tetra-aqua-bis{(E)-2-cyano-1-[(ethoxy-carbon-yl)methyl-sulfan-yl]-2-(1-naphthyl-amino-carbon-yl)ethene-1-thiol-ato}calcium(II) diethyl ether disolvate

In the title compound, [Ca(C(18)H(15)N(2)O(3)S(2))(H(2)O)(4)]·2C(4)H(10)O, the Ca atom, which lies on an inversion centre, is coordinated octa-hedrally by four water mol-ecules and two anions of the ketene dithio-acetal, the donor atoms of which are the amidic carbonyl O atoms. The central backbone of the ligands (excluding the naphthalene and oxoethyl groups) is essentially planar (r.m.s. deviation 0.035 Å). Intra-molecular hydrogen bonds are observed from the NH group to the formally 'thiol-ate' S atom and from one coordinated water to the nitrile group and to the ether O atom. Inter-molecular hydrogen bonds from the second independent water mol-ecule to the thiol-ate S atom and the side-chain oxo group connect the mol-ecules in chains parallel to the a axis.