Aminopyrimidines and Derivatives. 271.-Synthesis,Anticancer and Antimicrobiological Activities of 7-Glycopyranosyl-Pyrrolo[2,3-D]Pyrimidines2

Abstract

Reaction between 4-(O-acetyl-β-D-glycopyranosylamino)-6-oxopyrimidines 1 and chloroacetaldehyde leads to the corresponding 7-glycopyranosyl-4-oxopyrrolo [2,3-d]pyrimidines 3 in moderate yields. The reaction of 1a yields also 4-glucopyranosylaminofuro[2,3-d] pyrimidine 2. The anticancer and antimicrobiological activities of these products are noticed.     

Studies on Nucleosides: Part XXVIII1. Synthesis of 4-Amino (or Hydroxy)-6-Methylthio-1-(3′-Deoxy-β- D-ribofuranosyl)-1-H-pyrazolo[3, 4-d]Pyrimidines

Abstract

4-Amino-6-methylthio-1-(3′-deoxy-β-D-ribofuranosyl)-1H-pyrazolo-[3, 4-d]pyrimidine (11) and 6-methylthio-4(5H)-oxo-1-(3′-deoxy-β-D-ribofuranosyl)-1H-pyrazolo[3, 4-d]pyrimidine (12) have been synthesized from 1, 2-di-O-acetyl-5-O-benzoyl-3-deoxyribofuranose (5) and 4, 6-bis (methylthio)-1H-pyrazolo-[3, 4-d]pyrimidine (6). in a convergent fashion. Structural proofs are based on MS, IR, ¹H NMR, ¹³C NMR and elemental analyses.     

Nucleosides 137. Synthetic Modifications at the 2′Position of Pyrrolo[3,2-D]Pyrimidine and Thieno[3,2-D]Pyrimidine C-Nucleosides,Synthesis of “2′-Deoxy-9-Deazzadenosine” and of “9-Deaza ARA-A”

Abstract

The syntheses and preliminary biological evaluation of several novel pyrrolo[3,2-d]pyrimidine and thieno[3,2-d]pyrimidine C-nucleosides incorporating the arabinofuranosyl or 2′-deoxyribofuranosyl sugar moiety are described. The 2′-deoxy thieno[3,2-d]pyrimidine C-nucleosides (15 and 16) were obtained from 7-(β-D-ribofuranosyl)-4-oxo-3H-thieno[3,2-d]pyrimidine (3) and its 4-SMe derivative 8. “2”-Deoxy-9-deazaadenosine (31), “9-Deaza ara-A” (38) and the 2′-substituted arabinosyl pyrrolo[3,2-d]pyrimidine C-nucleosides (42 - 44) were synthesized from 4-amino-7-(2,3-O-isopropylidene-5-O-trityl-β-D-ribofuranosyl)-5H-pyrrolo[3,2-d]pyrimidine (21)     

A convenient synthesis of 6-amino-1-beta-D-ribofuranosylpyrazolo[3,4-d]pyrimidin-4-one and related 4,6-disubstituted pyrazolopyrimidine nucleosides

The glycosylation of 4,6-dichloropyrazolo[3,4-d]pyrimidine and 4-chloro-6-methylthiopyrazolo[3,4-d]pyrimidine via the corresponding trimethylsilyl intermediate and tetra-O-acetyl-beta-D-ribofuranose in the presence of trimethylsilyl triflate as a catalyst, gave selective glycosylation at N1 as the only nucleoside product. The intermediates 4,6-dichloro-1-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)pyrazolo [3,4-d]pyrimidine 7 and 4-chloro-6-methylthio-1-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)pyrazolo [3,4-d]pyrimidine 13 gave new and convenient synthetic routes to the inosine analog 1, the guanosine analog 2, the adenosine analog 3, and the isoguanosine analog 16. Glycosylation of the trimethylsilyl derivative of 6-chloropyrazolo[3,4-d]pyrimidine-4-one unexpectedly gave the N2-glycosyl isomer 20 as the major product. A number of new 4,6-disubstituted pyrazolo[3,4-d]pyrimidine nucleosides were prepared from these glycosyl intermediates.     

Nucleosides,III1 Synthesis and Properties of 2-Trifluoromethyl-Naphthimidazole-Ribonucleoside

Abstract

The fusion reaction between 2-trifluoromethylnaphth[2,3-d]imidazole (1) and 1-0-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose (2) leads to 2,3′,5′-tri-O-benzoyl-1-β-D-ribofuranosylnaphth[2,3-d]imidazole (3). Debenzoylation of (3) gives the corresponding nucleoside 1-β-D-ribofuranosyl -2-trifluoromethylnaphth[2,3-d]imidazole (4). Structural proofs are based on elementary analysis, UV-and ¹H-NMR spectra.     

Nucleosides,LVIII1 Synthesis of Base - Modified Oligonucleotides Containing 6- and 7-Aryl Lumazines

Abstract

6-Phenyl-, 7-phenyl-, 6-(4-biphenyl)- 7-(4-biphenyl)lumazine N-1-2-deoxy-β-D-ribofuranosides were synthesized, then converted into the corresponding 5′-O-dimethoxytrityl-3′-O-(β-cyanoethyl, N,N-diisopropyl)phosphoramidites and incorporated into different positions of self-complementary oligonucleotides. The influence of modifications on the melting temparature of the resulting duplexes was studied.

     

Synthesis of C-6 Pyrimidine Acyclic Nucleoside Analogs as Potential Antiviral Agents

Abstract

A number of pyrimidine acyclic nucleosides in which the acyclic moiety is attached to the C-6 position rather than N-1 of the pyrimidine ring have been prepared. This was accomplished via treatment of lithiated 2,4-dimethoxy-5,6-dimethylpyrimidine, or, 2,4-dimethoxy-6-methylpyrirnidine with 1,3-bis-(benzyloxy)-2-propanone, benzyl chloromethyl ether or oxirane, respectively, to give the corresponding key intermediates 6-[3-benzyloxy-2-[(benzyloxy)methyl]-2-hydroxypropyl]-2,4-dimethoxy-5-methylpyrimidine (2a), 6-[3-Denzyloxy-2-[(benzyloxy)methyl]-2-hydroxypropyl]-2,4-dimethoxypyrimidine(2b), 6-(2-benzyloxyethyl)-2,4-dimethoxy-5-methylpyrimidine (3), and2,4-dunethoxy-6-(3-hydroxypropyl)-5-methylpyrimidine (4a). After acidic hydrolysis, followed by debenzylation with boron trichloride these key intermediates were converted to the target C-6 pyrimidine acyclic derivatives. Compounds 6–8b, 11–13, 15, 16, 20, 22, 26, and 29–32 were evaluated for activity against herpes viruses and human immunodeficiency virus. None of the compounds were active against the viruses nor were they cytotoxic at the highest concentration tested.     

Metabolism of pyrazolo(3,4-d)pyrimidines in Leishmania braziliensis and Leishmania donovani. Allopurinol, oxipurinol, and 4-aminopyrazolo(3,4-d)pyrimidine.

Leishmania donovani and Leishmania braziliensis grown in culture formed millimolar concentrations of allopurinol ribonucleoside 5'-monophosphate from [6-14C]allopurinol. In addition, allopurinol 1-ribonucleoside, oxipurinol riboside 5'-monophosphate, and three new metabolites of allopurinol, namely, 4-aminopyrazolo(3,4-d)pyrimidine ribonucleoside 5'-monophosphate and the corresponding di- and triphosphates (1-ribosyl 4-aminopyrazolo(3,4-d)pyrimidine 5'-diphosphate and 1-ribosyl 4-aminopyrazolo(3,4-d)pyrimidine 5'-triphosphate) were identified in the parasitic cells. They were formed via a unique amination reaction from 1-ribosyl allopurinol 5'-phosphate, analogous to the conversion of IMP to AMP. [6-14C]Allopurinol was incorporated into RNA of L. donovani in the form of 4-aminopyrazolo(3,4-d)pyrimidine. Adenine reversed the growth inhibition of allopurinol and prevented its metabolism to all of the ribonucleotide metabolites. L. donovani was 2- to 4-fold more active in its metabolism of allopurinol to ribonucleotides than L. braziliensis. 4-Aminopyrazolo(3,4-d)pyrimidine inhibited cell growth and resulted in high intracellular levels of 1-ribosyl allopurinol 5'-phosphate and smaller amounts of the 4-aminopyrazolo(3,4-d)pyrimidine ribonucleotides. The metabolism of allopurinol to 4-aminopyrazolo(3,4-d)pyrimidine ribonucleotides and its resultant cytotoxicity occurs in these parasitic protozoans, but not in mammalian cells.     

Production of Ribotides of 4-Hydroxy- and 4-Aminopyrazolo[3, 4-d]pyrimidine by Brevibacterium ammoniagenes

Brevibacterium ammoniagenes ATCC 6872 was previously reported to accumulate large amounts of IMP, AMP, ADP, ATP, GMP, GDP and GTP from the corresponding purine bases. The organism was also reported to convert various derivatives of purine and 8-azapurine to the corresponding ribotides.

Using the similar process, ribotidation of pyrazolo[3, 4-d]pyrimidines was attempted, and it was found that the same organism was able to produce remarkable amounts of 4-hydroxy-1-β-d-ribofuranosylpyrazolo[3, 4-d]pyrimidine 5′-monophosphate (HPP-RP) from 4-hydroxypyrazolo[3, 4-d]pyrimidine (HPP, allopurinol) and 4-amino-1-β-d-ribofuranosylpyrazolo[3, 4-d]pyrimidine 5′-monophosphate and 5′-diphosphate from 4-amino-pyrazolo[3, 4-d]pyrimidine.

The crystals of HPP-RP (Na-salt) were isolated from the cultured broth of Br. ammoniagenes incubated with HPP, and characterized based on UV-spectra, IR-spectrum, NMR and others.

It was also found that HPP-RP was converted to the corresponding riboside by hydrolysis in aqueous solution (pH 4.0 ~ 9.0) for 6 hr at 140°C. The hydrolysis of HPP-RP was also accomplished with various organisms.     

FUNCTIONALIZATION OF PYRIMIDINE AND PURINE NUCLEOSIDES AT C4 AND C6: C-NUCLEOPHILIC SUBSTITUTION OF THEIR C4- AND C6-(1,2,4-TRIAZOL-1-YL) DERIVATIVES

A study of C-nucleophilic substitution at the C4-position on pyrimidine and C6-position on 2′-deoxyguanosine to produce novel nucleosides is presented with the spectroscopic properties of their respective substitution products. C4-(1,2,4-triazol-1-yl) pyrimidine nucleosides 1 were treated with nitroalkanes, malononitrile, acetylacetone, ethyl nitroacetate, acetoacetate and cyanoacetate at 100°C in dioxane in the presence of DBU resulting in the production of novel nucleosides 2–11. To explore the application of this methodology to purine chemistry, this approach was used to produce novel analogs from 2′-deoxyguanosine. We found that the triazolo derivative 12 undergoes C-nucleophilic substitution with nitromethane, malononitrile, acetylacetone, ethyl nitroacetate and cyanoacetate in the presence of potassium carbonate (K₂CO₃) in DMF at 100°C to give novel nucleosides 13–7.     

Ring-Opening of 3-β-D-Ribofuranosyl-3,7,8,9-Tetrahydropyrimido [1,2-i]Purin-8-ol and Preparation of 2-Thio- and 2-aza-Adenosine Derivatives

The adduct 3-β-D-ribofuranosyl-3,7,8,9-tetrahydropyrimido[1,2-i]purin-8-ol (2), obtained from adenosine and epichlorohydrin, underwent ring fission at basic conditions. The initial ring-opening took place at C2 of the pyrimidine unit resulting in 2-(5-amino-1-β-D-ribofuranosyl-imidazol-4-yl)-1,4,5,6-tetrahydropyrimidin-5-ol (3). Also the tetrahydropyrimidine ring of 3 could be opened resulting in 5-amino-1-(β-D-ribofuranosyl)-imidazole-4-(N-3-amino-2-hydroxyl-propyl)-carboxamide (4). In hot acid conditions, 2 was both deglycosylated and ring-opened yielding 2-(5-amino-imidazol-4-yl)-1,4,5,6-tetrahydropyrimidin-5-ol (7) as the final product. When reacting 3 with CS₂ or HNO₂ ring-closure took place and 3-β-D-ribofuranosyl-3,4,7,8,9-pentahydropyrimido[1,2-i]purin-8-ol-5-thione (5), and 3-β-D-ribofuranosyl-imidazo[4,5-e]-3,7,8,9-tetrahydropyrimido[1,2-c][1,2,3]triazine-8-ol (6), respectively, were obtained. Also, the pyrimidine ring of the epichlorohydrin adduct with adenine, 10-imino-5,6-dihydro-4H,10H-pyrimido[1,2,3-cd]purin-5-ol (10), underwent ring fission and the product was identified as 3-hydroxy-1,2,3,4-tetrahydroimidazo[1,5-a]pyrimidine-8-carboximidamide (11).     

A New Route for the Synthesis of 4-Amino-5-Fluoro-7-(2′-Deoxy-2′-Fluoro-2′-C-Methyl-β-d- Ribofuranosyl)-1H-Pyrrolo[2,3-D]Pyrimidine

A new route for the synthesis of the anti-HCV nucleoside analogue, 4-amino-5-fluoro-7-(2′-deoxy-2′-fluoro-2′-C-methyl-β-d-ribofuranosyl)-1H-pyrrolo[2,3-d]pyrimidine 1, was developed.     

Synthesis in Nucleoside Antibiotics

Both ribofuranoside (3) and ribopyranoside (5) of 4-amino-5-cyano-6-methy lmercaptopyr-rolo[2,3-d]pyrimidine (analogs of toyocamycin) have been synthesized for the first time by the fusion procedure using bis-(p-nitrophenyl) hydrogen phosphate as catalyst. Evidence for the β-configuration has been provided by analyzing the NMR spectra and ORD curves. The tumor-inhibitory activity of 3 against EhrIich ascites carcinoma in mice has also been examined.     

Solid-phase Parallel Synthesis of 4-β-D-Ribofuranosylpyrazolo[4,3-d]pyrimidine Nucleosides

The synthesis of pyrazolo[4,3-d]pyrimidine nucleoside library using solid-phase parallel synthesis methodology is described. Glycosylation of the trimethylsilyl (TMS) derivative of 1- and 2-(methyl)-1H and 2H-pyrazolo[4,3-d]pyrimidine-5,7-(4H,6H)-dione (5) with 1-O-acetyl-2,3,5-tri-O-benzoyl-D-ribofuranose in the presence of TMS triflate provided two novel protected nucleosides 6 and 7. The structures of 6 and 7 were assigned by 1H and 2D NMR experiments. Nucleosides 6 and 7 were then transformed to the key intermediates 12 and 15 respectively. Reaction of 12 and 15 with MMTCl resin in the presence of 2,6-lutidine afforded the necessary scaffolds B and C. Different amines (96) were introduced selectively by nucleophilic substitution on scaffolds B and C using solid-phase parallel semi-automated synthesizer. Cleavage of the products from the solid support with 30% HFIP in a parallel fashion yielded nucleoside libraries simultaneously, and they were analyzed and characterized by high-throughput LC-MS.     

Studies on Glycosides of 3, 4, 6-Trisubstituted Pyrazolo-[3, 4-D]Pyrimidines. Synthesis of 2′-Deoxyribonucleosides

Abstract

A synthesis of 4,6-dimethylthio-1-(2-deoxy-β-D-erythro-pentofuranosyl)pyrazolo[3,4-d]pyrimidine-3-carbonitrile (4) is described using the stereospecific sodium salt glycosylation procedure. Condensation of the sodium salt of 4,6-dimethylthiopyrazolo[3,4-d]pyrimidine-3-carbonitrile (1) with 1-chloro-2-deoxy-3,5-di-O-p-toluoyl-α-D-eythro-pentofuranose (2) gave exclusively the corresponding blocked nucleoside (3) with β-anomeric configuration, which on deprotection provided 2′-deoxyriboside 4. Aglycone functional groups transformations of 4 led to related 3,4,6-trisubstituted pyrazolo[3,4-d]pyrimidine-2′-deoxynucleosides. These compounds are devoid of any significant cytotoxic activity in vitro.     

O6-(4-Nitrophenyl)inosine and -Guanosine as Chromogenic Substrates for Adenosine Deaminase

Abstract

O⁶-(4-Nitrophenyl)inosine (la), O⁶ -(4-nitrophenyl)guanosine (1c) and O⁶ -(4-methylumbelliferonyl)inosine (2) were obtained by reaction of 6-chloro-9-(β-D-ribofuranosyl)purine (3a) or 2-amino-6-chloro-9-(β-D-ribofuranosyl)purine (3c) with sodium salts of 4-nitrophenol or 4-methylumbelliferone in N,N-dimethylformamide. Similarly, 6-chloro-9-(β-D-2,3-isopropylideneribofuranosyl)purine (3b) was transformed to 2′,3′-O-isopropylidene-O⁶-(4-nitrophenyl)inosine (1b). Deprotection of 1b with CF₃COOH gave compound la and O⁶ -(4-nitrophenyl)hypoxanthine (4). Compounds 1a and 1c are substrates for adenosine deaminase releasing 4-nitrophenol which is readily detected visually or spectrophotomemcally. Rate and extent of hydrolysis of la are significantly increased in the presence of purine nucleoside phosphorylase but xanthine oxidase has no influence. A potential fluorogenic analogue 2 is not a substrate for adenosine deaminase.

     

Synthesis of Pyrazolo[3, 4-d]Pyrimidine Ribonucleoside 3′, 5′-Cyclic Phosphates Related to cAMP,cIMP and cGMP1

Abstract

The synthesis of pyrazolo[3,4-d]pyrimidine ribonucleoside 3′, 5′-cyclic phosphates related to cAMP, cIMP and cGMP has been achieved for the first time. Phosphorylation of 4-amino-6-methylthio-1-β-D-ribo-furanosylpyrazolo[3,4-d]pyrimidine (1) with POCl₃ in trimethyl phosphate gave the corresponding 5′-phosphate (2a). DCC mediated intramolecular cyclization of 2a gave the corresponding 3′, 5′-cyclic phosphate (3a), which on subsequent dethiation provided the cAMP analog 4-amino-1-β-D-ribofuranosylpyrazolo[3, 4-d]pyrimidine 3′, 5′-cyclic phosphate (3b). A similar phosphorylation of 6-methylthio-1-β-D-ribofuranosylpyrazolo[3, 4-d]pyrimidin-4(5H)-one (5), followed by cyclization with DCC gave the 3′, 5′-cyclic phosphate of 5 (9a). Dethiation of 9a with Raney nickel gave the cIMP analog 1-β-D-ribofuranosylpyrazolo[3, 4-d]pyrimidin-4(5H)-one 3′, 5′-cyclic phosphate (9b). Oxidation of 9a with m-chloroperoxy benzoic acid, followed by ammonolysis provided the cGMP analog 6-amino-1-β-D-ribofuranosylpyrazolo [3, 4-d] pyrimidin-4(5H)-one 3′, 5′-cyclic phosphate (7). The structural assignment of these cyclic nucleotides was made by UV and H NMR spectroscopic studies.     

Synthesis of Quinazoline C-Nucleosides: A New Class of 6:6 Bicyclic Purine-Like Analogues.1

Abstract

The quinazoline C-nucleoside congeners of adenosine (1) and inosine (2) have been obtained by radical-induced addition of 4-bromobutyronitrile to C-ribosyl acrylonitrile 10. A base-catalyzed Ziegler-Thorpe cyclization of the dinitrile thus obtained (11) followed by aromatization with DDQ afforded key intermediate 6-ribosylated anthranilonitrile 14 and its α-isomer. Annulation of a pyrimidine ring onto 14 or onto the corresponding o-amino-amide followed by deblocking with MeOH/HCl finally gave 1 or 2 respectively.     

Synthesis of 5-chloroformycin A, 5-chloro-2''-deoxyformycin A and certain related 5,7-disubstituted 3-beta-D-ribofuranosylpyrazolo[4,3-d] pyrimidines from formycin A.

A facile synthesis of 7-amino-5-chloro-3-beta-D-ribofuranosylpyrazolo [4,3-d]pyrimidine (5-chloroformycin A, 6), 7-amino-5-chloro-3-(2-deoxy-beta-D-erythro-pentofuranosyl) pyrazolo [4,3-d]-pyrimidine (5-chloro-2'-deoxyformycin A, 13) and certain related 5,7-disubstituted pyrazolo[4,3-d]pyrimidine ribonucleosides is described starting with formycin A. Thiation of tri-O-acetyloxoformycin B (4b) with phosphorus pentasulfide, followed 3-beta-D-ribofuranosyl-7-thioxopyrazolo[4,3-d] pyrimidin-5(1H,4H,6H)-one (3b) in excellent yield. Chlorination of 4b with either phosphorus oxychloride or phenyl phosphonicdichloride furnished the key intermediate 5,7-dichloro-3-(2,3, 5-tri-O-acetyl-beta-D-ribofuranosyl)pyrazolo[4,3-d]pyrimidine (5a), which on deacetylation afforded 5,7-dichloro-3-beta-D-ribofuranosylpyrazolo [4,3-d]pyrimidine (5b). Ammonolysis of 5a with liquid ammonia gave 6, whereas with MeOH/NH3, a mixture of 6 and 7-methoxy-5-chloro-3-beta-D-ribofuranosylpyrazolo[4,3-d]pyrimidine (7) was obtained. Reaction of 6 with lithium azide and subsequent hydrogenation afforded 5-aminoformycin A (10). Treatment of 5a with thiourea gave 5-chloro-3-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl) pyrazolo[4,3-d]pyrimidine-7(1H,6H)-thione (8a), which on further reaction with sodium hydrosulfide furnished 3-beta-D-ribofuranosylpyrazolo [4,3-d]pyrimidine-5,7(1H,4H,6H)-dithione (11). The four-step deoxygenation procedure using phenoxythiocarbonylation of the 2'-hydroxy group of the 3', 5'-protected 6 gave 5-chloro-2'-deoxyformycin A (13).     

Nucleosides,XL1 Synthesis and Properties of lin-Naphthamidazole-Ribonucleosides

Abstract

The fusion reaction between 1-trimethylsilyl-naphth[2,3-d]imidazole (3) and its 2-methyl derivative (4) with 2, 3, 5-tri-O-benzoyl-1-bromo-D-ribofuranose (6) leads to anomeric mixtures of the corresponding 2', 3', 5'-tri-O-benzoyl-1α- and β-D-ribofuranosylnaphth[2,3-d]imidazoles (7, 11 and 13). Separation of the anomers was achieved by chromatographical means and debenzoylation yielded the corresponding nucleosides (8, 12 and 10, 14). Structural proofs are based on elementary analysis, UV- and ¹H-NMR spectra.