Synthesis, cytotoxicity, and antiviral activity of certain 7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine nucleosides related to toyocamycin and sangivamycin

A number of 7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine derivatives related to the nucleoside antibiotics toyocamycin and sangivamycin were prepared and tested for their biological activity. Treatment of the sodium salt of 4-amino-6-bromo-5-cyanopyrrolo[2,3-d]pyrimidine (1) with (2-acetoxyethoxy)methyl bromide (2) afforded a mixture of 4-amino-6-bromo-5-cyano-7-[(2-acetoxyethoxy)methyl]pyrrolo[2,3-d] pyrimidine (3) and the corresponding N1 isomer. Debromination of this mixture gave the corresponding 4-amino-5-cyano-7-[(2-acetoxyethoxy)-methyl]pyrrolo[2,3-d]pyrimidi ne (4) and 4-amino-5-cyano-1-[(2-acetoxyethoxy)methyl]pyrrolo[2,3-d]pyrimidin e (5). Deacetylation of 4 and 5 furnished 4-amino-5-cyano-7-[(2-hydroxyethoxy)methyl]pyrrolo[2,3-d]pyrimidine (6) and the corresponding N1 isomer (7), respectively. The sites of attachment for the acyclic moiety for 6 and 7 were assigned on the basis of UV spectral studies as well as 13C NMR spectroscopy. Conventional functional group transformation of 6 provided a number of novel 5-substituted derivatives (8-10), including the sangivamycin derivative 8. The methyl formimidate derivative 10 was converted to the thioamide derivative 11 and the carbohydrazide derivative 12. Compounds 6 and 8-12 were tested for cytotoxicity to L1210 murine leukemic cells in vitro. None of these compounds caused significant inhibition of cell growth. Evaluation of compounds 4 and 6-12 for activity against human cytomegalovirus (HCMV) and herpes simplex virus type 1 (HSV-1) revealed that only the thioamide (11) was active. It inhibited HCMV but not HSV-1 at concentrations producing only slight cytotoxicity in human foreskin fibroblasts (HFF cells) and KB cells.     

Synthesis and antiviral activity of some 7-[(2-hydroxyethoxy)methyl]pyrazolo[3,4-d]pyrimidine analogues of sangivamycin and toyocamycin

The sodium salt of 4-amino-3-cyanopyrazolo[3,4-d]pyrimidine (1) was condensed with (2-acetoxyethoxy)methyl bromide (2) to provide the corresponding protected acyclic nucleoside, 4-amino-3-cyano-1-[(2-acetoxyethoxy)methyl]-pyrazolo[3,4-d]pyrimid ine (3). Treatment of 3 with sodium methoxide in methanol provided a good yield of methyl 4-amino-1-[(2-hydroxyethoxy)methyl]pyrazolo[3,4-d]pyrimidine-3- formimidate (4). Treatment of the imidate (4) with sodium hydrogen sulfide gave the thiocarboxamide derivative 5. Aqueous base transformed 4 into 4-amino-1-[(2-hydroxyethoxy)methyl]pyrazolo[3,4-d]pyrimidine-3- carboxamide (6) in good yield. Treatment of 5 with mercuric chloride furnished the toyocamycin analogue 7. Evaluation of compounds 1, 3-7 revealed that only the heterocycle (1) and the thiocarboxamide acyclic nucleoside (5) were active. Compound 5 was the more potent with activity against human cytomegalovirus and herpes simplex virus type 1.     

Synthesis of classical, three-carbon-bridged 5-substituted furo[2,3-d]pyrimidine and 6-substituted pyrrolo[2,3-d]pyrimidine analogues as antifolates

Bridge homologation of the previously reported classical two-carbon-bridged antifolates, a 5-substituted 2,4-diaminofuro[2,3-d]pyrimidine (1) [which is a 6-regioisomer of LY231514 (Alimta)] and a 6-subsituted 2-amino-4-oxopyrrolo[2,3-d]pyrimidine, afforded the three-carbon-bridged antifolates analogues 4 and 5, with enhanced inhibitory activity against tumor cells in culture (EC(50) values in the 10(-8)-10(-7) M range or less). These two analogues were synthesized via a 10-step synthetic sequence starting from methyl 4-bromobenzoate (14), which was elaborated to the alpha-chloromethyl ketone (8) followed by condensation with 2,6-diamino-pyrimidin-4-one (7) to afford the substituted furo[2,3-d]pyrimidine 9 and the pyrrolo[2,3-d]pyrimidine 10. Subsequent coupling of each regioisomer with diethyl-l-glutamate followed by saponification afforded 4 and 5. The biological results indicate that elongation of the C8-C9 bridge of the classical 5-substituted 2,4-diaminofuro[2,3-d]pyrimidine and 6-substituted 2-amino-4-oxopyrrolo[2,3-d]pyrimidine are highly conducive to antitumor activity in vitro, despite a lack of increase in inhibitory activity against the target enzymes. This supports our original hypothesis that truncation of the B-ring of a highly potent 6-6 ring system to a 6-5 ring system can be compensated by bridge homologation to restore the overall length of the molecule.     

Synthesis and biological evaluation of acyclic 3-[(2-hydroxyethoxy)methyl] analogues of antiviral furo- and pyrrolo[2,3-d]pyrimidine nucleosides

The remarkably potent and specific activity against varicella-zoster virus (VZV) shown by 2'-deoxynucleosides of furo[2,3-d]pyrimidin-2(3H)-one and related ring systems is dependent on key structural features including the length and nature of the side-chain at C6 and the structure and stereochemistry of the sugar moiety at N3. Removal of the 3'-hydroxyl group from potent anti-VZV 2'-deoxynucleosides results in loss of the VZV activity, but such 2',3'-dideoxynucleoside analogues have shown anti-HCMV activity. We now report acyclic analogues with comparable side-chains at C6, but with the sugar moiety at N3 replaced with the (2-hydroxyethoxy)methyl group (present in the antiherpes drug acyclovir). Examples of both furo[2,3-d]- and pyrrolo[2,3-d]pyrimidin-2(3H)-one acyclic analogues were prepared and evaluated in a number of virus-infected cells and in tumor cell cultures. Certain of the long-chain analogues showed activity against VZV and HCMV. No significant activity against other DNA and RNA virus replication or against tumor cell proliferation was observed.     

Synthesis of classical, four-carbon bridged 5-substituted furo[2,3-d]pyrimidine and 6-substituted pyrrolo[2,3-d]pyrimidine analogues as antifolates

We report, for the first time, the biological activities of four-carbon-atom bridged classical antifolates on dihydrofolate reductase (DHFR), thymidylate synthase (TS), and folylpolyglutamate synthetase (FPGS) as well as antitumor activity. Extension of the bridge homologation studies of classical two-carbon bridged antifolates, a 5-substituted 2,4-diaminofuro[2,3-d]pyrimidine (1) and a 6-subsituted 2-amino-4-oxopyrrolo[2,3-d]pyrimidine (2), afforded two four-carbon bridged antifolates, analogues 5 and 6, with enhanced FPGS substrate activity and inhibitory activity against tumor cells in culture (EC(50) < or = 10(-7) M) compared with the two-carbon bridged analogues. These results support our original hypothesis that the distance and orientation of the side chain p-aminobenzoyl-L-glutamate moiety with respect to the pyrimidine ring are a crucial determinant of biological activity. In addition, this study demonstrates that, for classical antifolates that are substrates for FPGS, poor inhibitory activity against isolated target enzymes is not necessarily a predictor of a lack of antitumor activity.     

Evaluation of the anti-inflammatory activity of some pyrrolo[2,3-d]pyrimidine derivatives

A series of novel pyrrolo[2,3-d]pyrimidine and fused pyrrolo[2,3-d]pyrimidine derivatives were synthesized and their structures were characterized by elemental analysis, ¹H NMR, IR, and mass spectroscopy. Their in vivo anti-inflammatory activities were evaluated, and the results indicated that some of the title compounds compounds showed significant activities. These compounds are 2b ((7-(4-Methoxyphenyl)-5,6-diphenyl-7H-pyrrolo[2,3-d]pyrimidin-4-yl)-hydrazine), 7b (4-(2-(Benzyl)hydrazinyl)-7-(4-methoxyphenyl)-5,6-diphenyl-7H-pyrrolo[2,3-d] pyrimidine), 7d (4-(2-(Benzyl)hydrazinyl)-7-(4-methoxyphenyl)-5-phenyl-7H-pyrrolo[2,3-d]pyrimidine), and 9b (4-(3,5-Dimethyl-4H-pyrazol-1-yl)-7-(4-Methoxyphenyl)-5,6-diphenyl-4,7dihydro-3H-pyrrolo[2,3-d]pyrimidine).     

Nucleic acid related compounds. 51. Synthesis and biological properties of sugar-modified analogues of the nucleoside antibiotics tubercidin, toyocamycin, sangivamycin, and formycin

Treatment of 7-amino-3-beta-D-ribofuranosylpyrazolo[4,3-d]pyrimidine (formycin) with alpha-acetoxyisobutyryl bromide followed by deprotection of the resulting trans-vicinal acetoxy bromides and hydrogenolysis of the separated bromohydrins gave 2'-deoxy-(23%) and 3'-deoxyformycin (32%) after complete deprotection and purification of their hydrochloride salts. An analogous sequence gave 3'-deoxytoyocamycin and/or 3'-deoxysangivamycin in approximately 80% yields from toyocamycin. Antiviral, antineoplastic, and antimetabolic effects were evaluated for the formycin compounds and 4-amino-7-beta-D-ribofuranosylpyrrolo[2,3-d]pyrimidine (tubercidin), its 5-cyano- (toyocamycin), and 5-carbamoyl-(sangivamycin) antibiotic congeners in comparison with their 2'-deoxy, 3'-deoxy, and arabino analogues. In all cases, the modified-sugar compounds were less cytotoxic than the parent antibiotics. The majority also exhibited lower antiviral potency. However, the xylo-tubercidin analogue retained potent antiherpes 1 and 2 activity with decreased cytotoxicity. Labeled metabolite studies suggested that effects of these compounds on RNA and/or protein synthesis might be more significant than interference with DNA synthesis.     

Synthesis and biological evaluation of some pyrrolo[2,3-d]pyrimidines

Pyrrolo[2,3-d]pyrimidine and tetrazolopyrimidine derivatives 2a, b-5a, b were prepared. Also, acyclic and cyclic C-nucleosides 7a, b-12a, b were prepared by treating compound 6 with some aldoses. All prepared products were tested for antiviral activity against hepatitis-A virus (HAV, MBB-cell culture adapted strain) and herpes simplex virus type-1 (HSV-1). Plaque reduction infectivity assay was used to determine virus count reduction as a result of treatment with tested compounds. Compound 2a showed the highest effect on HAV, while compound 11b showed the highest effect on the HSV-1 virus.     

Synthesis and ring transformation of pyrrolo[2,3-d][1,3]oxazine to pyrrolo[2,3-d]pyrimidines

A convenient route is reported for the synthesis of fused pyrrolo [2, 3-d] [1, 3]-oxazine and pyrrolo [2, 3-d]-pyrimidine derivatives from 2-amino-1-benzyl-3-t-butoxycarbonyl-4, 5-dimethylpyrrole.     

Synthesis and activity of novel 5-substituted pyrrolo[2,3-d]pyrimidine analogues as pp60(c-Src) tyrosine kinase inhibitors

Therapy with receptor tyrosine kinase inhibitors provides an improved treatment option in a number of diseases such as cancer, myocardial infection, osteoporosis, stroke, and neurodegeneration. We have designed, synthesized, and evaluated a series of novel 2-amino-5-[(benzyl)imino]methyl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidine-4-one 7a and 2-amino-5-[(substituted-benzyl)imino]methyl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidine-4-one 7b-e derivatives as potential tyrosine kinase inhibitors. These compounds were synthesized by condensation reaction using 2-tritylamino-4-oxo-4,7-dihydro-3H-pyrrolo[2,3-d]pyrimidine-5-carbaldehyde 5 and appropriate benzylamines followed by detritylation. Compounds were evaluated for their inhibitory activity toward tyrosine phosphorylation for the pp60c-Src tyrosine kinase. Compounds 7a, 7d, and 7e demonstrated potent inhibitory activities against pp60c-Src tyrosine kinase with IC50 values of 13.9, 34.5, and 78.4 microM, respectively. Dihalogenated compounds 7d and 7e have 3 to 7-times lower IC50 values than that of the parent compound 7a.     

Synthesis and cytotoxicity of 4-amino-5-oxopyrido[2,3-d]pyrimidine nucleosides

A number of nucleoside analogues have been either used clinically as anticancer drugs or evaluated in clinical studies, while new nucleoside analogues continue to show promise. In this article, we report synthesis and cytotoxicity of a series of new pyrido[2, 3-d]pyrimidine nucleosides. 2-Amino-3-cyano-4-methoxypyridine was converted, in two steps, to 4-amino-5-oxopyrido[2,3-d]pyrimidine. A variety of 1-O-acetylated pentose sugar derivatives were condensed with silylated 4-amino-5-oxopyrido[2,3-d]pyrimidine, followed by protection, to afford a series of 4-amino-5-oxopyrido[2, 3-d]pyrimidine nucleosides. Further derivatizations provided an additional group of pyrido[2,3-d]pyrimidine nucleosides. These nucleosides were evaluated for in vitro cytotoxicity to human prostate cancer (HTB-81) and mouse melanoma (B16) cells as well as normal human fibroblasts (NHF). A number of compounds (1a,b, 2a-c,f, 3f+4d) showed significant cytotoxicity to cancer cells, with 4-amino-5-oxo-8-(beta-D-ribofuranosyl)pyrido[2,3-d]pyrimidine (1b) being the most potent proliferation inhibitor (EC(50): 0.06-0.08 microM) to all types of cells tested. However, a selective inhibition to the cancer cells was observed for 4-amino-5-oxo-8-(beta-D-xylofuranosyl)pyrido[2,3-d]pyrimidine (2b), which is a potent inhibitor of HTB-81 (EC(50): 0.73 microM) and has a favorable in vitro selectivity index (28).     

Synthesis and antiviral activity of certain guanosine analogues in the thiazolo[4,5-d]pyrimidine ring system.

Several sugar-modified nucleoside derivatives of the purine analogue 5-amino-3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,7-dione (1) were synthesized. Phosphorylation of 1 using POCl3 resulted in 5'-monophosphate 2, which was subsequently converted to 3',5'-cyclic phosphate 3, by reported methods. 5'-Sulfamoyl derivative 4 was synthesized by treatment of the 2,3-O-isopropylidene derivative of 1 with chlorosulfonamide followed by acid deprotection. Compounds 5-7, the 5'-deoxy, the tri-O-acetyl, and the 2'-deoxy derivatives of 1, respectively, were synthesized by glycosylation of 5-aminothiazolo[4,5-d]pyrimidine-2,7-dione, the aglycon of 1, with the appropriate sugar moieties, utilizing the Vorbruggen procedure. Oxidative cleavage of the C2'-C3' bond in 1 followed by reduction with sodium borohydride led to "seco" analogue 8. Nucleosides 2-8 were evaluated for antiviral activity in vivo against the Semliki Forest virus. The activity of compounds 2, 5, and 7 were similar to that of 1. Cyclic phosphate 3 was toxic at the high dose and weakly active at the lower dose. Compounds 4, 6, and 8 were inactive in this system.     

Synthesis and antitumor activity of new pyrido[2,3-d]pyrimidine derivatives

New series of pyrido[2,3-d]pyrimidines such as; 5-(4-aryl-5-sulfanyl-4H-[1,2,4]triazol-3-yl) 1H,3H,8H-pyrido[2,3-d]pyrimidine-2,4,7-triones 6, 7; S-[3-(2,4,7-trioxo-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidin-5-yl)-4-(4-substituted phenyl)-4H-[1,2,4]triazol-5-yl]-2-(4-phenylpiperazin-1-yl)ethanethioates 10, 11; 2,4,7-trioxo-N′-[(4-substituted piperazin-1-yl)acetyl]-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidine-5-carbohydrazides 13–16 and N′-arylidene-2,4,7-trioxo-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidine-5-carbohydrazides 17–19 was synthesized through the reaction of the key intermediate 2,4,7-trioxo-1,2,3,4,7,8-hexahydropyrido[2,3-d]pyrimidine-5-carbohydrazide 3 with different reagents. The structures of the newly synthesized compounds were elucidated through microanalysis, IR, ¹H NMR, ¹³C NMR, and mass spectroscopy. These compounds have been subjected to in vitro antitumor evaluation by bleomycin-dependant DNA damage assay. The most active antitumor compound 6 was selected for further in vivo evaluation of antineoplastic activity against Ehrlich ascites carcinoma in mice. It was observed that our target compound has a potent antitumor activity.     

Synthesis, DNA-binding, and antiviral activity of certain pyrazolo[3,4-d]pyrimidine derivatives

Some new pyrazolo[3,4-d]pyrimidine derivatives have been prepared and tested for their antiviral and DNA-binding activities. Compounds 4, 5, and 6 showed high binding affinity to DNA at concentrations of 19, 27, and 28 micrograms/ml, respectively. On the other hand, compounds 6 and 10 reduced the number of viral plaques of Herpes simplex type-1 (HSV-1) by 66 and 41%, respectively. The detailed synthesis and spectroscopic and biological data are reported.     

Novel pyrrolo[2,3-d]pyrimidine antifolates: synthesis and antitumor activities.

New antifolates, characterized by a 6-5 fused ring system, a pyrrolo[2,3-d]pyrimidine ring, and a trimethylene bridge at position 5 (12a,b and 13a,b) were designed and efficiently synthesized. The synthetic method included (1) construction of the key intermediary acyclic skeleton, 5-[4-(tert-butoxycarbonyl)phenyl]- 2-(dicyanomethyl)pentanoates (6a,b), (2) cyclization with guanidine, followed by reduction to the pyrrolo[2,3-d]pyrimidine derivatives (8a,b and 9a,b), and (3) subsequent glutamate coupling and saponification. These antifolates were more growth-inhibitory by about 1 order of magnitude than methotrexate (MTX) against KB human epidermoid carcinoma cells and A549 human nonsmall cell lung carcinoma cells in in vitro culture. Growth inhibitory IC50 values for N-[4-[3-(2,4-diamino-7H-pyrrolo[2,3-d]pyrimidin-5- yl)propyl]benzoyl]-L-glutamic acid (12a) against KB and A549 were 0.27 and 4.5 ng/mL, while those for MTX were 5.0 and 35 ng/mL, respectively. Other members of this class of antifolates, 12b and 13a,b, showed good activities nearly equal to that of 12a.     

Novel synthesis and antifungal activity of pyrrole and pyrrolo[2,3-d]pyrimidine derivatives containing sulfonamido moieties

Several sulfonamides containing pyrroles (2a-c, 6a-d, 8a-d), pyrrolo[2,3-d] pyrimidines (3a-c), acetanilides (11a-c) and tetrahydrobenzothiophenes (13a-c) were synthesized starting from N4-chloroacetylsulfanilamides (1a-d). The structures of synthesized compounds were elucidated by elemental analyses and spectral data. Compounds 2b, 3b, 6b, 8b and 8d exhibited a remarkable antifungal activity compared with the standard fungicide mycostatine.     

呋喃[2,3-d]嘧啶核苷的化学合成 及抗水痘带状疱疹病毒活性的研究进展

摘要：呋喃[2,3-d]嘧啶核苷是一类新型的、特异性治疗水痘带状疱疹病毒的核苷前药。该文综述了近年来呋喃[2,3-d]嘧啶核苷衍生物的化学合成及其抗水痘带状疱疹病毒(varicella-zoster virus , VZV)活性研究进展。     

Progress in 7-deazapurine - pyrrolo[2,3-d]pyrimidine - ribonucleoside synthesis

This review reports on the synthesis of 7-deazapurine ribonucleosides, including C-nucleosides, 2'-C-methyl derivatives and L-enantiomers. It covers the various aspects of convergent nucleoside synthesis such as the Schiff base procedure, the fusion reaction, the metal salt procedures, the Silyl-Hilbert-Johnson reaction, and the nucleobase anion glycosylation. The review discusses the scope and limitations of glycosylation reactions performed on 7-deazapurines. Peracylated ribose derivatives were now employed in the glycosylation, which overcome difficulties reported earlier.