L-nucleosides containing modified nucleobases

The synthesis of base modified L-nucleosides is described with pyrrolo[2,3-d]pyrimidines, pyrazolo[3,4-d]pyrimidines, benzimidazoles, and imidazo[1,2-a]-s-triazines as nucleobases. The conformation of the nucleosides is studied and the antiviral activity is evaluated.     

Solid phase synthesis of structurally diverse pyrimido[4,5-d] pyrimidines for the potential use in combinatorial chemistry

An efficient solid phase synthesis of pyrimido[4,5-d]pyrimidine derivatives is described. Reaction of polymer-bound pyrimidine 1 with urea or thiourea followed by cleavage from the support provided 4-aminopyrimido[4,5-d]pyrimidines 4 and 5 while treatment of 6 with phenyl isocyanate or phenyl isothiocyanate followed by cleavage from resin afforded 3-phenylpyrimido[4,5-d]pyrimidines 9 and 10.     

Chlorotrimethylsilane-promoted one-pot synthesis of steroidal[17,16-d]pyrimidines

A novel and practical procedure was developed for the preparation of steroidal[17,16-d]pyrimidines by chlorotrimethylsilane (TMSCl)-promoted one-pot multicomponent Biginelli-like condensations of steroid-17-ones, urea and aromatic aldehydes. First, treatment of the steroid-17-ones with urea and aromatic aldehydes in dimethylformamide (DMF)/acetonitrile (ACN) gives the corresponding Biginelli products, following the aromatising reaction of the Biginelli products at the same time under air to yield the desired steroidal[17,16-d]pyrimidines (78-88%). Since steroidal[17,16-d]pyrimidines with hydroxyl group can be subsequently converted into steroidal[17,16-d]pyrimidine derivatives, this general method provides a highly efficient route to these biologically important compounds.     

Synthesis of 7-Glycopyranosyl-5-oxq-pyrrolo[2,3-d]Pyrimidine and 4-Glyco Pyranosylamino-Furo[2,3-d]Pyrimidine Derivatives

Abstract

The synthesis of some glycosyl derivatives of furo[2,3-d] and pyrrolo[2,3-d]pyrimidines is described.     

Anticytokinin activity of 4-substituted triazolo[4,5-d]pyrimidines and 4-substituted pyrazolo[3,4-d]pyrimidines

The synthesis and physiological activity of some novel 4-substituted triazolo[4,5-d]pyrimidines and 4-substituted pyrazolo[3,4-d]pyrimidines are described. Most of the compounds possessed high anticytokinin activity towards purine (benzyladenine) and phenylurea (4-PU-30) type cytokinins. 1-Benzyl-4-ethoxycarbonylpiperazinyl-1H-1,2,3-triazolo[4,5-d]pyrimidine almost completely removed cytokinin stimulated effects—betacyanin synthesis in Amaranthus caudatus cotyledons; growth of radish cotyledons and retention of chlorophyll in leaf explants. Some chemical structurephysiological activity relationships have been established.     

Design and synthesis of 7H-pyrrolo[2,3-d]pyrimidines as focal adhesion kinase inhibitors. Part 1

A series of 2-amino-9-aryl-7H-pyrrolo[2,3-d]pyrimidines were designed and synthesized to target focal adhesion kinase (FAK). A number of these pyrrolopyrimides exhibited low micromolar inhibitory activities against focal adhesion kinase, and their preliminary SAR was established via systematic chemical modifications. The 2-amino-9-aryl-7H-pyrrolo[2,3-d]pyrimidines represent a new class of kinase inhibitors.     

Discovery of novel c-Met kinase inhibitors bearing a thieno[2,3-d]pyrimidine or furo[2,3-d]pyrimidine scaffold

A series of thieno[2,3-d]pyrimidines and furo[2,3-d]pyrimidines were synthesized and evaluated for the c-Met inhibition. Thieno[2,3-d]pyrimidine 6b stood out as the most potent showing an IC(50) of 35.7 nM. This compound displayed high inhibitory effect on cell proliferation in BaF3-TPR-Met cells and showed high selectivity for c-Met family against other 14 tested kinases. However, compound 6b was found ineffective in the c-Met-dependent U-87MG human gliobastoma xenograft model that may be relevant to its poor PK profile.     

Antimicrobial and antitumor activity of N-heteroimmine-1,2,3-dithiazoles and their transformation in triazolo-, imidazo-, and pyrazolopirimidines.

The reaction of Appel's salt with o-amino nitrile heterocycles 10-19 gave the corresponding 4-chloro-5-heteroimmine-1,2,3-dithiazoles 20-29 which were evaluated for their antibacterial, antifungal and antitumor activity. Although all these N-heteroimines were devoid of significant antibacterial activity, they showed significant antifungal activity. Moreover, the same derivatives represent highly versatile intermediates in heterocyclic synthesis, in fact the pyrazoleimino dithiazoles 20-26 can be converted in one step into 2-cyano derivatives of the corresponding 4-methoxy-pyrazolo[3,4-d]pyrimidines 30-35 by sodium methoxide in refluxing methanol. This provides a general and attractive route to 4-methoxy-6-cyano pyrazolo[3,4-d]pyrimidines from 1-substituted 5-amino pyrazoles 10-19 in two simple steps. Finally, the isosteric replacement of the pyrazole ring atoms to give the imidazole[3,4-d]pyrimidine and triazole [4,5-d] pyrimidine ring systems was examined.     

Pyrrolo[2,3-d]pyrimidines containing an extended 5-substituent as potent and selective inhibitors of lck II

Pyrrolo[2,3-d]pyrimidines containing a 5-(4-phenoxyphenyl) substituent are novel, potent and selective inhibitors of lck in vitro. Exploration of C-6 position of the pyrrolo[2,3-d]pyrimidine and the terminal phenyl group structure-activity relationship (SAR) is detailed. Compound 1 is orally active in animal models.     

Syntheses of 2″,3″-Dideoxy-L-Glycero-Pentofuranosyl C-Nucleosides

Abstract

2′,3′ -Dideoxy-L-C-nucleosides, 4-amino-8-(2,3-dideoxy-L-glyceropento-furanosyl)pyrazolo[1,5-a]-1,3,5-triazines (9 and 10), 4-amino-7-(2,3-dideoxy-L-glycero-pentofuranosyl)-3H,5H-pyrrolo[3,2-d]pyrimidines (17 and 18), 7-(2,3-dideoxy-L-glyceropentofuranosyl)-4-oxo-3H,5H-pyrrolo[3,2-d]pyrimidines (23 and 24) and 2,4-diamino-5-(2,3-dideoxy-L-glyceropentofuranosyl)pyrimidines (28 and 29) have been synthesized from L-gulonic γ-lactone 1.     

Discovery and in vitro evaluation of potent kinase inhibitors: Pyrido[1',2':1,5]pyrazolo[3,4-d]pyrimidines

The discovery, synthesis, potential binding mode, and in vitro kinase profile of several pyrido[1',2':1,5]pyrazolo[3,4-d]pyrimidines as potent kinase inhibitors are discussed.     

Regiospecific one-pot synthesis of pyrimido[4,5-d]pyrimidine derivatives in the solid state under microwave irradiations

Electron rich 6-[(dimethylamino)methylene]amino uracil 1, undergoes [4+2] cycloaddition reactions with various in situ generated glyoxylate imine and imine oxides 6 to provide novel pyrimido[4,5-d]pyrimidine derivatives of biological significance, after elimination of dimethylamine from the (1:1) cycloadducts and oxidative aromatisation. This procedure provides a convenient method for the direct synthesis of pyrimido[4,5-d]pyrimidines in excellent yields when carried out in the solid state and under microwave irradiations.     

Design, synthesis, and structure-activity relationship studies of ATP analogues as DNA gyrase inhibitors

We report herein the design and synthesis of ATP-analogues, namely 4-amino-pyrazolo[3,4-d]pyrimidines and 4-amino-pyrazolo[1,5-a][1,3,5]triazines, with DNA gyrase inhibitory activity. Among these series, some compounds exhibited promising antibacterial activity.     

7-Pyrrolidinyl- and 7-piperidinyl-5-aryl-pyrrolo[2,3-d]pyrimidines--potent inhibitors of the tyrosine kinase c-Src

7-Heterocyclyl-5-aryl-pyrrolo[2,3-d]pyrimidines represent a new class of highly potent and selective inhibitors of the tyrosine kinase pp60(c-Src).     

Rational design of 4-amino-5,6-diaryl-furo[2,3-d]pyrimidines as potent glycogen synthase kinase-3 inhibitors

4-Amino-5,6-diaryl-furo[2,3-d]pyrimidines have been identified as inhibitors of glycogen synthase kinase-3beta (GSK-3beta). One representative derivative, 4-amino-3-(4-(benzenesulfonylamino)-phenyl)-2-(3-pyridyl)-furo[2,3-d]pyrimidine (12) exhibited potent GSK-3beta inhibitory activity in low nanomolar level of IC(50). The binding mode was proposed from a docking study.     

3-Aryl pyrazolo[4,3-d]pyrimidine derivatives: Nonpeptide CRF-1 antagonists

The synthesis of a series of 3-aryl pyrazolo[4,3-d]pyrimidines as potential corticotropin-releasing factor (CRF-1) antagonists is described. The effects of substitution on the aromatic ring, the amino group and the pyrazolo ring on CRF-1 receptor binding were investigated.     

Discovery and optimization of thieno[2,3-d]pyrimidines as B-Raf inhibitors

The serine/threonine specific protein kinase B-Raf is part of the MAPK pathway and is an interesting oncology target. We have identified thieno[2,3-d]pyrimidines as a core scaffold of small molecule B-Raf inhibitors. The SAR of analogs in this series will be described.     

Novel 4-amino-furo[2,3-d]pyrimidines as Tie-2 and VEGFR2 dual inhibitors

A novel class of furo[2,3-d]pyrimidines has been discovered as potent dual inhibitors of Tie-2 and VEGFR2 receptor tyrosine kinases (TK) and a diarylurea moiety at 5-position shows remarkably enhanced activity against both enzymes. One of the most active compounds, 4-amino-3-(4-((2-fluoro-5-(trifluoromethyl)phenyl)amino-carbonylamino)phenyl)-2-(4-methoxyphenyl)furo[2,3-d]pyrimidine (7k) is <3 nM on both TK receptors and the activity is rationalized based on the X-ray crystal structure.     

SAR studies on thiazolo[4,5-d]pyrimidine based CXCR2 antagonists involving a novel tandem displacement reaction

As part of a Lead Optimisation programme to identify small molecule antagonists of the human CXCR2 receptor, a series of substituted thiazolo[4,5-d]pyrimidines was prepared via the application of a novel tandem displacement reaction.     

4-Alkoxy-2-methylthiopyrrolo-[2,3-d]-pyrimidines. A new series of anti-cytokinins

A series of 4-alkoxy-2-methylthiopyrrolo[2,3-d] pyrimidines having alkoxy groups from methoxy to hexyloxy along with the parent 4-hydroxy compound have been tested for cytokinin and anticytokinin activity using tobacco tissue culture. None of the compounds showed any cytokinin activity but several of the compounds were strongly active as anticytokinins, the most active was 4-pentyloxy-2-methyl-thiopyrrolo[2,3-d] pyrimidine. Increasing or decreasing the chain length resulted in a lowering of activity; the hydroxy and methoxy compounds were totally inactive over the concentration range tested. The results are discussed in relation to steric and other considerations.