Pyrido[2,3-d]pyrimidin-7-one inhibitors of cyclin-dependent kinases

The identification of 8-ethyl-2-phenylamino-8H-pyrido[2, 3-d]pyrimidin-7-one (1) as an inhibitor of Cdk4 led to the initiation of a program to evaluate related pyrido[2, 3-d]pyrimidin-7-ones for inhibition of cyclin-dependent kinases (Cdks). Analysis of more than 60 analogues has identified some clear SAR trends that may be exploited in the design of more potent Cdk inhibitors. The most potent Cdk4 inhibitors reported in this study inhibit Cdk4 with IC(50) = 0.004 microM ([ATP] = 25 microM). X-ray crystallographic analysis of representative compounds bound to the related kinase, Cdk2, reveals that they occupy the ATP binding site. Modest selectivity between Cdks is exhibited by some compounds, and Cdk4-selective inhibitors block pRb(+) cells in the G(1)-phase of the cell division cycle.     

Pyrido[2,3-d]pyrimidin-7-ones as specific inhibitors of cyclin-dependent kinase 4

Inhibition of the cell cycle kinase, cyclin-dependent kinase-4 (Cdk4), is expected to provide an effective method for the treatment of proliferative diseases such as cancer. The pyrido[2,3-d]pyrimidin-7-one template has been identified previously as a privileged structure for the inhibition of ATP-dependent kinases, and good potency against Cdks has been reported for representative examples. Obtaining selectivity for individual Cdk enzymes, particularly Cdk4, has been challenging. Here, we report that the introduction of a methyl substituent at the C-5 position of the pyrido[2,3-d]pyrimidin-7-one template is sufficient to confer excellent selectivity for Cdk4 vs other Cdks and representative tyrosine kinases. Further optimization led to the identification of highly potent and selective inhibitors of Cdk4 that exhibit potent antiproliferative activity against human tumor cells in vitro. The most selective Cdk4 inhibitors were evaluated for antitumor activity against MDA-MB-435 human breast carcinoma xenografts in mice.     

Synthesis and structure-activity relationships of pyrazolo[4,3-d]pyrimidin-7-ones as adenosine receptor antagonists

A series of 21 1,3-dialkylpyrazolo[4,3-d]pyrimidin-7-ones substituted in the 5-position with various phenyl substituents has been synthesized and found to have affinity for the adenosine A1 receptor. The potency pattern due to substituents of the phenyl ring was found to parallel that found in a previously reported 1,3-dialkyl-8-phenylxanthine series. A quantitative structure-activity relationship was developed between these two series that correctly predicted the potencies of six additional 5-substituted pyrazolo[4,3-d]pyrimidines that were synthesized during the course of the analysis. With use of the correlation as a guide, one additional 5-phenylpyrazolo[4,3-d]pyrimidine containing a 4-[[(dimethylamino)ethyl]amino]sulfonyl substituent to improve aqueous solubility was prepared. On the basis of the high correlation between adenosine binding affinities of analogously substituted xanthines and pyrazolo-[4,3-d]pyrimidines and the close superposition of the heterocyclic rings and substituents that is apparent from molecular models of these two series, it is hypothesized they fit the receptor in an analogous fashion.     

Synthesis of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-ones as potential antimicrobial agents

Synthesis of new derivatives of pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-one via reaction of 7-(4-bromophenyl)-1,2-dihydro-5-(4-fluorophenyl)-2-thioxopyrido[2,3-d] pyrimidin-4(3H)-one with hydrazonoyl chlorides or reaction of 2-hydrazino-pyrido[2,3-d]pyrimidin-4(3H)-one with different aldehydes followed by cyclization of the products. All the newly synthesized compounds were evaluated for their antimicrobial activities and also their minimum inhibitory concentration against most of test organisms was performed. Amongst the tested compounds displayed excellent activity against all the tested microorganisms except SR and PA.     

磷酸二酯酶抑制剂吡唑并[4,3-d]嘧啶-7-酮类衍生物的研究

目的 寻找新型磷酸二酯酶抑制剂，设计合成未见文献文献报道的吡唑[4,3-d]嘧啶－7－酮类衍生物。方法 合成了8个新的衍生物，结构经IR,^1H-NMR和MS确证，并进行离体主动脉条和离体气管螺旋条药理实验。结果 目标化合物均具有一定的血管扩张作用和支气管扩经作用，其中Ⅸc的血管扩张作用优于对照药维拉帕米，Ⅸa的支握管扩张作用强于对照药氨茶碱。结论 吡唑并[4,3-d]嘧啶－7－酮类衍生物有可能开发成为新型选择性磷酸二酯酶抑制剂。     

Antitumor activity of novel pyrrolo[2,3-d]pyrimidin-4-ones

Pyrrolo[2,3-d]pyrimidine is known to have a broad spectrum of biological activities, including antitumor activity. The cytotoxic properties of six novel pyrrolo[2,3-d]pyrimidin-4-ones in vitro were investigated on four different human cancer cell lines. Meanwhile, the role of apoptosis was explored. Malignant cells were cultured in RPMI medium and incubated with different concentrations. Cell viability was quantitated by MTT assay. Apoptotic cells were determined using DAPI (4'-6-diamidino-2-phenylindole) and propidium iodide staining of DNA fragmentation by flow cytometry (sub-G1 peak). We have identified new analogs as a novel class of antiproliferative agents by a cell-based screening method. All compounds inhibited the growth of malignant cells in a dose-dependent manner. The IC?? of compounds 4 and 5 as the two most potent analogs was determined as 122.4 and 106.7 μM in HeLa cells, respectively. Compounds 4 and 5 induced a sub-G1 peak in the flow-cytometry histogram of treated cells, compared to control, indicating that apoptotic cell death is involved in compound 4- and 5-induced toxicity. In conclusion, compounds 4 and 5 exert cytotoxic effects in different cancer cell lines in which apoptosis plays an important role. Thus, compounds 4 and 5 could be considered as potential chemotherapeutic agents.     

Antitumor activity of novel pyrrolo[2,3-d]pyrimidin-4-ones

Pyrrolo[2,3-d]pyrimidine is known to have a broad spectrum of biological activities, including antitumor activity. The cytotoxic properties of six novel pyrrolo[2,3-d]pyrimidin-4-ones in vitro were investigated on four different human cancer cell lines. Meanwhile, the role of apoptosis was explored. Malignant cells were cultured in RPMI medium and incubated with different concentrations. Cell viability was quantitated by MTT assay. Apoptotic cells were determined using DAPI (4′-6-diamidino-2-phenylindole) and propidium iodide staining of DNA fragmentation by flow cytometry (sub-G1 peak). We have identified new analogs as a novel class of antiproliferative agents by a cell-based screening method. All compounds inhibited the growth of malignant cells in a dose-dependent manner. The IC₅₀ of compounds 4 and 5 as the two most potent analogs was determined as 122.4 and 106.7 μM in HeLa cells, respectively. Compounds 4 and 5 induced a sub-G1 peak in the flow-cytometry histogram of treated cells, compared to control, indicating that apoptotic cell death is involved in compound 4– and 5–induced toxicity. In conclusion, compounds 4 and 5 exert cytotoxic effects in different cancer cell lines in which apoptosis plays an important role. Thus, compounds 4 and 5 could be considered as potential chemotherapeutic agents.     

Synthesis of non-nucleosides: 7- and 1,3-substituents of new pyrrolo[2,3-d]pyrimidin-4-ones on antiviral activity

A series of non-nucleosides 9-47 were synthesized. Compounds 1-4 were reacted with formic acid (85%) to afford compounds 5-8. Then, the latter compounds were reacted with alkyl halides a-f (2-bromopropane, 2-bromobutane, benzyl bromide, benzyl chloromethyl ether, chloromethyl ethyl ether, phenacyl bromide) in the presence of NaH in dry DMF to give the desired compounds 9-47, which were evaluated for activity against herpes simplex virus type-II (HSV-II).     

6-Chloro-1,2,4-triazolo[4,3-b]pyrido[2,3-d]-and [3,2-d]pyridazines - Synthesis and Structure Determination

5,8-Dichloropyrido[2,3-d]pyridazine ( 2 ) gave with hydrazine hydrate in dioxane 5-chloro-8-hydrazino- and 8-chloro-5-hydrazinopyrido[2,3-d]pyridazines 3 and 4 . When 3 and 4 were allowed to react with formic acid they gave a mixture of the 6-chloro-1,2,4-triazolo[4,3-b]pyrido[2,3-d] - and [3,2-d]pyridazines ( 5 and 6 ).     

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.     

新型吡唑并[4,3-d]嘧啶衍生物的合成和抗炎活性

目的为了研发新型抗炎药,设计合成了一种新的吡唑并[4,3-d]嘧啶衍生物,并揭示了新化合物可能的抗炎机制。方法在显微镜下观察细胞的形态变化;通过Griess法测定新型化合物对脂多糖刺激的RAW264.7细胞中NO产生的影响;通过qRT-PCR评估TNF-α、IL-6和IL-1β的基因相对转录水平;通过qRT-PCR和Western blot测量环氧化酶-2表达,以及对NF-κB/NLRP3炎症小体信号通路进行检测。小鼠体内实验通过HE染色观察肺组织变化。结果该新型化合物借助NF-κB/NLRP3炎症小体信号通路可有效抑制RAW264.7细胞中NO的产生以及COX-2、TNF-α、IL-6和IL-1β的表达。同时,它还可以改善细胞的形态和缓解小鼠急性肺损伤。结论新型吡唑并[4,3-d]嘧啶衍生物通过NF-κB/NLRP3炎症小体信号通路来产生抗炎活性。     

Heterocyclen via Mannichbasen, 7. Mitt. Synthese von Pyrazolo[1,5-a]pyrido[2,3-d]pyrimidin-9(4H)-onen

Heterocycles via Mannich Bases, VII: Synthesis of Pyrazolo[1,5-a]pyrido[2,3-d]pyrimidin-9(4H)-ones The title compounds 4 are synthesised from 5-amino-3-methylpyrazolo[1,5-a]pyrimidin-7(4H)-one (2) and ketone Mannich bases or dehydro Mannich bases.     

Synthesis and structure-activity relationships of 3H-quinazolin-4-ones and 3H-pyrido[2,3-d]pyrimidin-4-ones as CXCR3 receptor antagonists

CXC chemokine receptor-3 (CXCR3) is a G-protein coupled receptor (GPCR) predominantly expressed on activated T lymphocytes that promote Th1 responses. Previously, we described the 3H-quinazolin-4-one containing VUF 5834 (decanoic acid {1-[3-(4-cyano-phenyl)-4-oxo-3,4-dihydro-quinazolin-2-yl]-ethyl}-(2-dimethylamino-ethyl)-amide) as a small-molecule CXCR3 antagonist with submicromolar affinity and as a lead structure for the development of CXCR3 antagonists. More recently, the related 3H-pyrido[2,3-d]pyrimidin-4-one compounds AMG 487 and NBI-74330 have been reported as nanomolar CXCR3 antagonists and these ligands are currently under clinical investigation. The aim of this study is to link the structure-activity relationship (SAR) of the previously published class of 3H-quinazolin-4-one containing CXCR3 ligands with these novel clinical candidates. From the modification of the lead structure VUF 5834 emerged the importance of the (4-fluoro-3-(trifluoromethyl)phenyl)acetyl and the 3-methylen-pyridine as substituents to improve the affinity at the human CXCR3 receptor, whereas other features are less important. The described molecules serve as tool to investigate the role of the CXCR3 receptor in various inflammatory conditions.     

Synthesis and antimicrobial activity of some thiazolinyl tetrahydrobenzo[b]thiophenes and thiazolinyl tetrahydrobenzothieno[2,3-d]pyrimidin-4-ones.

Two series of novel 3-carbethoxy-2-(3',4'-disubstituted-2',3'- dihydrothiazol-2'-ylidenamino)-4,5,6,7-tetrahydrobenzo[b] thiophenes (3a-o) and 2-methyl-3-(3',4'-disubstituted-2',3'-dihydrothiazol-2'-ylidena mino-5,6,7,8- tetrahydrobenzothieno[2,3-d]pyrimidin-4(3H) ones (8a-o) have been synthesized and tested for antimicrobial activity. All members of the series have been found to exhibit in vitro antibacterial and/or antifungal activities. Activity was optimized by cyclization to the thienopyrimidin-4-ones. In particular, compounds 8e and 8fd were the most active against the 3 tested microorganisms. Their antifungal activity was higher than that exhibited by nystatin while their MIC was found to be nearly equal to that of nystatin.     

Synthesis and pharmacological activity of 3-substituted pyrido[3',2':4,5]thieno[3,2-d]pyrimidin-4(3H)-ones

A series of 3-substituted pyridothienopyrimidin-4(3H)-ones has been synthesized from 2,7,9-trimethyl-4H-pyrido[3',2':4,5]thieno-[3,2-d] [ 1,3]oxazin-4-one. These compounds have been evaluated for analgesic, anti-inflammatory and antipyretic activities. The ulcerogenic effect of the compounds has been also studied.     

Synthesis of pyrazole and pyrazolo [4,3-d] pyrimidinone derivatives. II

Three new series of pyrazolic and pyrazolo-pyrimidinonic derivatives (II a-g), (III a-g) and (IV a-g), containing the substituted phenyl-hydrazide moiety were prepared and studied in order to check some information on the analgesic and antipyretic activity of an analogous series obtained in a previous work. Some derivatives (II b), (II d), (II f), (III b), (III c) and (IV d) show interesting analgesic activity.     

Synthesis of pyrazole derivatives and pyrazolo[4,3-d]pyrimidines. I

Three series of pyrazole derivatives (III a-g), (IV a-g) and (V a-g) were synthesized and tested for analgesic, antipyretic and antiinflammatory activity. Many of tested compounds showed interesting analgesic and antipyretic activity, whereas no compounds exhibited any antiinflammatory activity.