2-(b-D-Ribofuranosyl)-4-(p-tolylazo)-5-trifluoromethyl-2,4-dihydropyrazol-3-one

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Synthesis and Antitumor Activity of 5-Trifluoromethyl-2,4- dihydropyrazol-3-one Nucleosides

2,4-Dihydropyrazole glucosides 3a-3c were prepared and tested for theirantitumor activity. The structures of these compounds were established by 1H and 13C-NMR spectroscopy. Glucoside 3b shows an in vitro IC50 value of 16.4 μM againstproliferation of the human promyelotic leukemia (HL60) cell line

A facile synthesis of pyrimido[2<i>"</i>,3<i>"</i>:5<i>'</i>,1′]pyrazolo [3′,4′:4,5]pyrimido[1,6-<i>a</i>] benzimidazoles and [1,2,4]triazino[3<i>"</i>,4<i>"</i>:5<i>'</i>, l′]pyrazolo[3′,4′:4,5]-pyrimido[6,1-<i>a</i>]benzimidazoles

284-289Thieno[2',3':4,5]pyrimido[1 ,6-a]benzimidazoles 4-7 have been synthesized by the reaction of 3-mercaptopyrimido[1,6-a]benzimidazole with halo ketones and halo esters, respectively. 3-Aminopyrazolo[3',4':5,6]pyrimido[1,6-a]benzimidazole 9 reacted with acetylacetone, ethyl acetoacetate, ethyl benzoyl acetate, ethyl α-chloroacetoacetate and β-aryl acyanoacrylonitriles to give pyrimido[2",3":5',1']pyrazolo[3',4':4,5]pyrimido[1,6-a]benzimidazoles 13, 14a,b, 15, 19a-e, respectively. Diazonium salt 20 coupled with each of malononitrile, benzoylacetonitrile, ethyl cyanoacetatc, acetylacetone, diethyl malonate and β-keto esters to give [1,2,4]triazino[3",4":5',1']pyrazolo[3',4' :4,5]pyrimido[6,1-a] benzimidazoles 21-25a,b, respectively. Structures of the synthesized compounds are confirmed on the basis of elemental analyses, and spectral data

<span style="font-size:21.0pt;mso-bidi-font-size:14.0pt">A facile synthesis of [1,2,4]triazino[<span style="font-size:22.0pt;mso-bidi-font-size:15.0pt;mso-bidi-font-style:italic">4<i>,</i>5<i>-a</i><span style="font-size:21.0pt;mso-bidi-font-size:14.0pt">]benzimidazoles, pyrazolo[5,1-<i style="mso-bidi-font-style:normal">c</i>]triazines), triazolo[5,1<i>-c </i>]triazines and pyrido[1<i>,</i><span style="mso-bidi-font-style:italic">2<i>-a </i>]benzimidazoles </span></span></span></span>

202-209Triazino[4,5-a]benzimidazoles <b style="mso-bidi-font-weight: normal">4 and 9 have been obtained by coupling of arenediazonium chlorides with ethyl (1-ethoxycarbonyl)benzimidazole-2-acetate. Pyrazolo[5,1-c ]triazines 8a-c and triazolo[5,1-c ]triazines 8d have been synthesized via coupling of diazotized heterocyclic amines with ethyl benzimidazole-2-acetate 1. Ethyl benzimidazole-2-acetate 1 reacts with 1,1-dicyano-2-substituted ethenes 13 and 1-cyano- 1-ethoxycarbonyl- 2-substituted ethenes 17 to give pyrido[1,2-a ]benzimidazoles 14 and <b style="mso-bidi-font-weight: normal">23, respectively. Compound 14 can be converted to 16 by hydrogen peroxide. Structures of the newely synthesised compounds are confirmed on the basis of elemental analyses, spectral data and alternative methods whenever possible.</span