Nucleosides and nucleotides. 107. 2-(cycloalkylalkynyl)adenosines: adenosine A2 receptor agonists with potent antihypertensive effects.

Abstract:

:Adenosine receptor-binding profiles in rat brain tissues and antihypertensive effects in spontaneously hypertensive rats (SHR) of a series of 2-(cycloalkylalkynyl)adenosines (2-CAAs) and their congeners are described. The structure-activity relationship of this series of compounds is discussed, focusing on the length of the alkynyl side chain and bulkiness of the terminal cycloalkyl substituents in terms of binding activity and cardiovascular effects. All the 2-CAAs had a preferential affinity for A2 receptors. Of these derivatives, 2-(3-cyclopentyl-1-propyn-1-yl)adenosine (10b) exhibited the most selective affinity for A2 receptors (Ki ratio: A1/A2 = 70) on the basis of receptor binding. In the C-2 binding region of adenosine, compounds often have potent and/or selective A2 activity from introduction of an acetylenic group at the C-2 position followed by one methylene residue further followed by a hydrophobic substituent such as a cycloalkyl ring at the terminal position of the alkynyl side chain. Intravenous injection of 10b up to 100 micrograms/kg had a potent hypotensive effect without a marked decrease in heart rate in anesthetized SHR. Compounds 10j-s, with a hydroxyl group in the C-3" position of the alkynyl side chain, had a potent affinity for both A1 and A2 receptors, but they were not highly selective for A2 receptors. These compounds caused a marked bradycardia upon intravenous administration in anesthetized SHR. Oral administration of 10b (0.1-1 mg/kg) had a potent and long-lasting antihypertensive effect in conscious SHR.

journal_name

J Med Chem

authors

Abiru T,Miyashita T,Watanabe Y,Yamaguchi T,Machida H,Matsuda A

doi

10.1021/jm00090a017

keywords:

subject

Has Abstract

pub_date

1992-06-12 00:00:00

pages

2253-60

issue

12

eissn

0022-2623

issn

1520-4804

journal_volume

35

pub_type

杂志文章
  • Evaluation of potent and selective small-molecule antagonists for the CXCR2 chemokine receptor.

    abstract::N,N'-Diarylureas were prepared, and the structure-activity relationship relative to the CXCR2 receptor was examined. This led to the identification of a potent and highly selective CXCR2 antagonist, which in addition was shown to be functionally active both in vitro against human neutrophils and in vivo in rabbit mode...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm034248l

    authors: Widdowson KL,Elliott JD,Veber DF,Nie H,Rutledge MC,McCleland BW,Xiang JN,Jurewicz AJ,Hertzberg RP,Foley JJ,Griswold DE,Martin L,Lee JM,White JR,Sarau HM

    更新日期:2004-03-11 00:00:00

  • Comparative structure-activity relationships of antifolate triazines inhibiting murine tumor cells sensitive and resistant to methotrexate.

    abstract::The inhibitory effect of 108 4,6-diamino-1,2-dihydro-2,2-dimethyl-1-(substituted-phenyl)-s-triazines on murine L5178Y tumor cells, resistant and sensitive to methotrexate (MTX), has been studied. From the pI50 values, quantitative structure-activity relationships have been formulated which show that the lipophilic tri...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00369a019

    authors: Selassie CD,Hansch C,Khwaja TA,Dias CB,Pentecost S

    更新日期:1984-03-01 00:00:00

  • Methyl analogues of the experimental Alzheimer drug phenserine: synthesis and structure/activity relationships for acetyl- and butyrylcholinesterase inhibitory action.

    abstract::With the goal of developing potential Alzheimer's pharmacotherapeutics, we have synthesized a series of novel analogues of the potent anticholinesterases phenserine (2) and physostigmine (1). These derivatives contain methyl (3, 4, 6), dimethyl (5, 7, 8, 10, 11) and trimethyl (14) substituents in each position of the ...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm010080x

    authors: Yu Q,Holloway HW,Flippen-Anderson JL,Hoffman B,Brossi A,Greig NH

    更新日期:2001-11-22 00:00:00

  • Development of Potent and Selective Pyrazolopyrimidine IRAK4 Inhibitors.

    abstract::A series of pyrazolopyrimidine inhibitors of IRAK4 were developed from a high-throughput screen (HTS). Modification of an HTS hit led to a series of bicyclic heterocycles with improved potency and kinase selectivity but lacking sufficient solubility to progress in vivo. Structure-based drug design, informed by cocryst...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/acs.jmedchem.9b00439

    authors: Bryan MC,Drobnick J,Gobbi A,Kolesnikov A,Chen Y,Rajapaksa N,Ndubaku C,Feng J,Chang W,Francis R,Yu C,Choo EF,DeMent K,Ran Y,An L,Emson C,Huang Z,Sujatha-Bhaskar S,Brightbill H,DiPasquale A,Maher J,Wai J,McKenzi

    更新日期:2019-07-11 00:00:00

  • Reversible ketomethylene-based inhibitors of human neutrophil proteinase 3.

    abstract::Neutrophil serine proteases, proteinase 3 (PR3) and human neutrophil elastase (HNE), are considered as targets for chronic inflammatory diseases. Despite sharing high sequence similarity, the two enzymes have different substrate specificities and functions. While a plethora of HNE inhibitors exist, PR3 specific inhibi...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm500782s

    authors: Budnjo A,Narawane S,Grauffel C,Schillinger AS,Fossen T,Reuter N,Haug BE

    更新日期:2014-11-26 00:00:00

  • Crystal, solution, and molecular modeling structural properties and muscarinic antagonist activity of azaprophen.

    abstract::The structure of azaprophen, which was originally assigned by 1H NMR analysis, was confirmed by X-ray crystallography. A comparison of 13C NMR isotropic chemical shift data for azaprophen in the solid state and in CDCl3 and DMSO-d6 solution was used to correlate solution and solid-state conformation as determined by t...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00108a030

    authors: Carroll FI,Abraham P,Mascarella SW,Singh P,Moreland CG,Sankar SS,Kwon YW,Triggle DJ

    更新日期:1991-04-01 00:00:00

  • Mode of action of 4-hydroxyphenylpyruvate dioxygenase inhibition by triketone-type inhibitors.

    abstract::A series of 2-(2-nitrobenzoyl)cyclohexane-1,3-dione analogues (1-9) were designed, synthesized, and evaluated for inhibition of 4-hydroxyphenylpyruvate dioxygenase (4-HPPD), a key enzyme involved in the catabolism of tyrosine which catalyzes the conversion of 4-hydroxyphenylpyruvate to homogentisate. The correlations ...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm010568y

    authors: Wu CS,Huang JL,Sun YS,Yang DY

    更新日期:2002-05-23 00:00:00

  • Crystal structure and anti herpes simplex virus activity of 2,2'-anhydro-1-beta-D-arabinofuranosylthymine.

    abstract::1-beta-D-Arabinofuranosylthymine (aThy; ara-T) is a potent selective anti herpes simplex virus drug. Its anhydro analogue, 2,2'-anhydro-aThy, was shown to be 9-fold less active and at least 3-fold less toxic than aThy. This compound was relatively stable at physiological pH and in strong acid but was rapidly hydrolyze...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00354a025

    authors: Harrison DH,Schinazi RF,Rubin BH

    更新日期:1982-12-01 00:00:00

  • Nontoxic Metal-Cyclam Complexes, a New Class of Compounds with Potency against Drug-Resistant Mycobacterium tuberculosis.

    abstract::Tuberculosis (TB) accounted for 1.5 million deaths in 2014, and new classes of anti-TB drugs are required. We report a class of functionalized 1,8-disubstituted cyclam derivatives that display low micromolar activity against pathogenic mycobacteria. These compounds inhibit intracellular growth of Mycobacterium tubercu...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/acs.jmedchem.6b00432

    authors: Yu M,Nagalingam G,Ellis S,Martinez E,Sintchenko V,Spain M,Rutledge PJ,Todd MH,Triccas JA

    更新日期:2016-06-23 00:00:00

  • Synthesis and anticancer activity comparison of phenylalkyl isoselenocyanates with corresponding naturally occurring and synthetic isothiocyanates.

    abstract::Synthesis and identification of novel phenylalkyl isoselenocyanates (ISCs), isosteric selenium analogues of naturally occurring phenylalkyl isothiocyanates (ITCs), as effective cytotoxic and antitumor agents are described. The structure-activity relationship comparison of ISCs with ITCs and effect of the increasing al...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm800993r

    authors: Sharma AK,Sharma A,Desai D,Madhunapantula SV,Huh SJ,Robertson GP,Amin S

    更新日期:2008-12-25 00:00:00

  • Structure-activity relationships of antibacterial 6,7- and 7,8-disubstituted 1-alkyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acids.

    abstract::Previous quantitative and qualitative structure-activity studies in antibacterial monosubstituted 1-ethyl-1,4-dihydro-4-oxoquinoline-3-carboxylic acids prompted us to synthesize the 6,7,8-polysubstituted compounds. In this paper, the preparation and antibacterial activity of the 6,7- and 7,8-disubstituted compounds an...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00186a014

    authors: Koga H,Itoh A,Murayama S,Suzue S,Irikura T

    更新日期:1980-12-01 00:00:00

  • 5-Cyano-2'-deoxyuridine 5'-phosphate: a potent competitive inhibitor of thymidylate synthetase.

    abstract::The 5'-phosphate (1) of the antiviral nucleoside 5-cyano-2'-deoxyuridine was synthesized and evaluated for inhibition of thymidylate synthetase purified from methotrexate-resistant Lactobacillus casei. Compound 1 was a potent competitive inhibitor with a K1 of 0.55 microns. Irreversible enzyme inhibition by this compo...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00195a028

    authors: Chang CT,Edwards MW,Torrence PF,Mertes MP

    更新日期:1979-09-01 00:00:00

  • Structure-activity relationships of bifunctional peptides based on overlapping pharmacophores at opioid and cholecystokinin receptors.

    abstract::Cholecystokinin (CCK) has been identified as a pronociceptive endogenous peptide which also possesses antiopioid actions. CCK may be upregulated in conditions of chronic pain or during sustained morphine administration resulting in attenuation of opioid-mediated pain relief. These complex interactions between opioids ...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm050921q

    authors: Agnes RS,Lee YS,Davis P,Ma SW,Badghisi H,Porreca F,Lai J,Hruby VJ

    更新日期:2006-05-18 00:00:00

  • Synthesis and structure-activity relationships of nonpeptide, potent triazolone-based angiotensin II receptor antagonists.

    abstract::2,5-Dibutyl-2,4-dihydro-4-[[2-(1H-tetrazol-5-yl)[1,1'-biphenyl]-4' - yl]methyl]-3H-1,2,4-triazol-3-one, SC-51316, was synthesized as a potent and orally active angiotensin II (AII) receptor antagonist with a long duration of action. To explore the lipophilic pocket in the AII receptor interacting with the substituent ...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00067a015

    authors: Huang HC,Reitz DB,Chamberlain TS,Olins GM,Corpus VM,McMahon EG,Palomo MA,Koepke JP,Smits GJ,McGraw DE

    更新日期:1993-07-23 00:00:00

  • Synthesis and quantitative structure-activity relationship of imidazotetrazine prodrugs with activity independent of O6-methylguanine-DNA-methyltransferase, DNA mismatch repair, and p53.

    abstract::The antitumor prodrug temozolomide is compromised by its dependence for activity on DNA mismatch repair (MMR) and the repair of the chemosensitive DNA lesion, O6-methylguanine (O6-MeG), by O6-methylguanine-DNA-methyltransferase (E.C. 2.1.1.63, MGMT). Tumor response is also dependent on wild-type p53. Novel 3-(2-anilin...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm401121k

    authors: Pletsas D,Garelnabi EA,Li L,Phillips RM,Wheelhouse RT

    更新日期:2013-09-12 00:00:00

  • Discovery and early development of TMC647055, a non-nucleoside inhibitor of the hepatitis C virus NS5B polymerase.

    abstract::Structure-based macrocyclization of a 6-carboxylic acid indole chemotype has yielded potent and selective finger-loop inhibitors of the hepatitis C virus (HCV) NS5B polymerase. Lead optimization in conjunction with in vivo evaluation in rats identified several compounds showing (i) nanomolar potency in HCV replicon ce...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm401396p

    authors: Cummings MD,Lin TI,Hu L,Tahri A,McGowan D,Amssoms K,Last S,Devogelaere B,Rouan MC,Vijgen L,Berke JM,Dehertogh P,Fransen E,Cleiren E,van der Helm L,Fanning G,Nyanguile O,Simmen K,Van Remoortere P,Raboisson P,Vendev

    更新日期:2014-03-13 00:00:00

  • 6- and 7-substituted 2-[2'-(dimethylamino)ethyl]-1,2-dihydro-3H-dibenz[de,h] isoquinoline-1,3-diones: synthesis, nucleophilic displacements, antitumor activity, and quantitative structure-activity relationships.

    abstract::New 2-[2'-(dimethylamino)ethyl]-3H-dibenz[de,h]isoquinoline-1,3-diones with substituents at the 6- and 7-positions were prepared. Nucleophilic aromatic displacement was a key reaction in the syntheses. Ten of the new compounds were more potent than the unsubstituted compound, azonafide, in a panel of tumor cells inclu...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm950742g

    authors: Sami SM,Dorr RT,Sòlyom AM,Alberts DS,Iyengar BS,Remers WA

    更新日期:1996-04-12 00:00:00

  • Drugs derived from cannabinoids. 2. Basic esters of nitrogen and carbocyclic analogs.

    abstract::Various basic esters of nitrogen (2) and carbocyclic (3 and 4) analogs of cannabinoids were synthesized using dicyclohexylcarbodiimide in methylene chloride. The compounds in the three series werw studied in selected pharmacological tests in mice, rats, dogs, and cats. It was shown that making the basic ester from the...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00226a002

    authors: Razdan RK,Terris BZ,Pars HG,Plotnikoff NP,Dodge PW,Dren AT,Kyncl J,Somani P

    更新日期:1976-04-01 00:00:00

  • Synthesis of malarial plasmepsin inhibitors and prediction of binding modes by molecular dynamics simulations.

    abstract::A series of inhibitors of the malarial aspartic proteases Plm I and II have been synthesized with L-mannitol as precursor. These inhibitors are characterized by either a diacylhydrazine or a five-membered oxadiazole ring replacing backbone amide functionalities. Molecular dynamics simulations were applied in the desig...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm050463l

    authors: Ersmark K,Nervall M,Hamelink E,Janka LK,Clemente JC,Dunn BM,Blackman MJ,Samuelsson B,Aqvist J,Hallberg A

    更新日期:2005-09-22 00:00:00

  • Novel Strategies To Activate the Dopamine D1 Receptor: Recent Advances in Orthosteric Agonism and Positive Allosteric Modulation.

    abstract::The five dopamine receptor subtypes (D1-5) are activated by the endogenous catecholamine dopamine. Sustained research has sought to identify selective ligands for receptor subtypes. In particular, activation of the D1 receptor has attracted attention due to its promising role in neurological diseases. Initial attempts...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章,评审

    doi:10.1021/acs.jmedchem.8b01767

    authors: Hall A,Provins L,Valade A

    更新日期:2019-01-10 00:00:00

  • Structural requirements for inhibition of the neuronal nitric oxide synthase (NOS-I): 3D-QSAR analysis of 4-oxo- and 4-amino-pteridine-based inhibitors.

    abstract::The family of homodimeric nitric oxide synthases (NOS I-III) catalyzes the generation of the cellular messenger nitric oxide (NO) by oxidation of the substrate L-arginine. The rational design of specific NOS inhibitors is of therapeutic interest in regulating pathological NO levels associated with sepsis, inflammatory...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm020074g

    authors: Matter H,Kotsonis P,Klingler O,Strobel H,Fröhlich LG,Frey A,Pfleiderer W,Schmidt HH

    更新日期:2002-07-04 00:00:00

  • Anticandidal activity of 5-fluorocytosine-peptide conjugates.

    abstract::An approach to the development of new anticandidal drugs is described that employs peptides as carriers of toxic agents into cells. 5-Flurorcytosine (5-FC) was chosen as a toxic agent with which to prepare 5-FC-peptide conjugates as models to test the carrier proposal. Model compounds were synthesized and then tested ...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00195a019

    authors: Steinfeld AS,Naider F,Becker JM

    更新日期:1979-09-01 00:00:00

  • Major effect of pyrrolic N-benzylation in norbinaltorphimine, the selective kappa-opioid receptor antagonist.

    abstract::Indolic N-benzylation of naltrindole reportedly extends the duration of delta-opioid receptor (DOR) antagonism. Similar modification of the kappa-opioid receptor (KOR) antagonist norBNI (1a) and its 17,17'-diNMe analogue (1d), a low potency mu-opioid receptor (MOR) partial agonist, was found to affect predominantly th...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm049172n

    authors: Chauvignac C,Miller CN,Srivastava SK,Lewis JW,Husbands SM,Traynor JR

    更新日期:2005-03-10 00:00:00

  • Conjugation of quinones with natural polyamines: toward an expanded antitrypanosomatid profile.

    abstract::A combinatorial library of quinone-polyamine conjugates designed to optimize the antitrypanosomatid profile of hit compounds 1 and 2 has been prepared by a solid-phase approach. The conjugates were evaluated against the three most important human trypanosomatid pathogens (Trypanosoma brucei rhodesiense, Trypanosoma cr...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm301112z

    authors: Lizzi F,Veronesi G,Belluti F,Bergamini C,López-Sánchez A,Kaiser M,Brun R,Krauth-Siegel RL,Hall DG,Rivas L,Bolognesi ML

    更新日期:2012-12-13 00:00:00

  • Contilisant, a Tetratarget Small Molecule for Alzheimer's Disease Therapy Combining Cholinesterase, Monoamine Oxidase Inhibition, and H3R Antagonism with S1R Agonism Profile.

    abstract::Contilisant, a permeable, antioxidant, and neuroprotectant agent, showing high nM affinity at H3R and excellent inhibition of the monoamine oxidases and cholinesterases, is an affine and selective S1R agonist in the nanomolar range, based on the binding affinity and functional experiment, a result confirmed by molecul...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/acs.jmedchem.8b00848

    authors: Bautista-Aguilera ÓM,Budni J,Mina F,Medeiros EB,Deuther-Conrad W,Entrena JM,Moraleda I,Iriepa I,López-Muñoz F,Marco-Contelles J

    更新日期:2018-08-09 00:00:00

  • Design, synthesis, and evaluation of oxygen-containing macrocyclic peptidomimetics as inhibitors of HCV NS3 protease.

    abstract::HCV infection is considered a silent epidemic because most people infected do not develop acute symptoms. Instead, the disease progresses to a chronic state leading to cirrhosis and hepatocarcinoma. Novel therapies are needed to combat this major health threat. The HCV NS3 serine protease has been the target of contin...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm801201u

    authors: Velázquez F,Venkatraman S,Blackman M,Pinto P,Bogen S,Sannigrahi M,Chen K,Pichardo J,Hart A,Tong X,Girijavallabhan V,Njoroge FG

    更新日期:2009-02-12 00:00:00

  • Synthesis and antitumor activity of cis-dichloroplatinum (II)-N-aminated nucleoside complexes.

    abstract::N-Aminated nucleoside complexes of cis-dichloroplatinum(II) were synthesized, and their antitumor activities against L1210 cells in mice and in vitro were studied. While the native nucleosides failed to show any antitumor activity, the complexes exhibited high antitumor activity and had no nephrotoxicity in mice. Stud...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00370a006

    authors: Maeda M,Abiko N,Uchida H,Sasaki T

    更新日期:1984-04-01 00:00:00

  • Methotrexate analogues. 33. N delta-acyl-N alpha-(4-amino-4-deoxypteroyl)-L-ornithine derivatives: synthesis and in vitro antitumor activity.

    abstract::N delta-Acyl derivatives of the potent folylpolyglutamate synthetase (FPGS) inhibitor N alpha-(4-amino-4-deoxypteroyl)-L-ornithine (APA-L-Orn) were synthesized from N alpha-(4-amino-4-deoxy-N10-formylpteroyl)-L-ornithine by reaction with an N-(acyloxy)succinimide or acyl anhydride, followed by deformylation with base....

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00402a013

    authors: Rosowsky A,Bader H,Cucchi CA,Moran RG,Kohler W,Freisheim JH

    更新日期:1988-07-01 00:00:00

  • Design, Synthesis, and Biological Evaluation of Linear Aliphatic Amine-Linked Triaryl Derivatives as Potent Small-Molecule Inhibitors of the Programmed Cell Death-1/Programmed Cell Death-Ligand 1 Interaction with Promising Antitumor Effects In Vivo.

    abstract::A series of novel linear aliphatic amine-linked triaryl derivatives as inhibitors of PD-1/PD-L1 were designed, synthesized, and evaluated in vitro and in vivo. In this chemical series, compound 58 showed the most potent inhibitory activity and binding affinity with hPD-L1, with an IC50 value of 12 nM and a KD value of...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/acs.jmedchem.0c01329

    authors: Guo J,Luo L,Wang Z,Hu N,Wang W,Xie F,Liang E,Yan X,Xiao J,Li S

    更新日期:2020-11-25 00:00:00

  • Novel 21-aminosteroids that inhibit iron-dependent lipid peroxidation and protect against central nervous system trauma.

    abstract::A novel class of 21-aminosteroids has been developed. Compounds within this series are potent inhibitors of iron-dependent lipid peroxidation in rat brain homogenates with IC50's as low as 3 microM. Furthermore, selected members enhance early neurological recovery and survival in a mouse head injury model. Significant...

    journal_title:Journal of medicinal chemistry

    pub_type: 杂志文章

    doi:10.1021/jm00166a010

    authors: Jacobsen EJ,McCall JM,Ayer DE,Van Doornik FJ,Palmer JR,Belonga KL,Braughler JM,Hall ED,Houser DJ,Krook MA

    更新日期:1990-04-01 00:00:00