Synthesis and biological evaluation of some novel isoxazoles and cyanopyridines, a new class of potential anti-tubercular agents

348-352<span style="font-size:15.0pt;mso-bidi-font-size:8.0pt;font-family:Fd34462-Identity-H; mso-bidi-font-family:Fd34462-Identity-H;color:#0C0C0C">Substituted chalcones <span style="font-size:13.5pt;mso-bidi-font-size: 6.5pt;font-family:Fd36020-Identity-H;mso-bidi-font-family:Fd36020-Identity-H; color:#0C0C0C">2a-m<span style="font-size:13.5pt;mso-bidi-font-size: 6.5pt;font-family:Fd36020-Identity-H;mso-bidi-font-family:Fd36020-Identity-H; color:#0C0C0C"> <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt; font-family:Fd34462-Identity-H;mso-bidi-font-family:Fd34462-Identity-H; color:#0C0C0C">prepared by the treatment of 5-benzoyl-benzimidazol-2-yl-o-benzoyl(4' –aminoaceto-phenone) <span style="font-size:14.0pt;mso-bidi-font-size: 7.0pt;font-family:Fd31402-Identity-H;mso-bidi-font-family:Fd31402-Identity-H; color:#0C0C0C">1<span style="font-size:14.0pt;mso-bidi-font-size: 7.0pt;font-family:Fd31402-Identity-H;mso-bidi-font-family:Fd31402-Identity-H; color:#0C0C0C"> <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt; font-family:Fd34462-Identity-H;mso-bidi-font-family:Fd34462-Identity-H; color:#0C0C0C">with araldehydes, on cyclisation with hydroxylamine  hydrochloride in ethanol furnish isoxazoles <span style="font-size:13.5pt;mso-bidi-font-size: 6.5pt;font-family:Fd36020-Identity-H;mso-bidi-font-family:Fd36020-Identity-H; color:#0C0C0C">3a-m<span style="font-size:13.5pt;mso-bidi-font-size: 6.5pt;font-family:Fd36020-Identity-H;mso-bidi-font-family:Fd36020-Identity-H; color:#0C0C0C">. <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt; font-family:Fd34462-Identity-H;mso-bidi-font-family:Fd34462-Identity-H; color:#0C0C0C">The <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt;font-family:Fd34462-Identity-H; mso-bidi-font-family:Fd34462-Identity-H;color:#0C0C0C">same chalcones on condensation with malononitrile yield cyanopyridines <span style="font-size:13.5pt;mso-bidi-font-size: 6.5pt;font-family:Fd36020-Identity-H;mso-bidi-font-family:Fd36020-Identity-H; color:#0C0C0C">4a-m<span style="font-size:13.5pt;mso-bidi-font-size: 6.5pt;font-family:Fd36020-Identity-H;mso-bidi-font-family:Fd36020-Identity-H; color:#0C0C0C">. <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt; font-family:Fd34462-Identity-H;mso-bidi-font-family:Fd34462-Identity-H; color:#0C0C0C">The structure of the compounds synthesised have been assigned on the basis of elemental analyses, IR and NMR spectral studies. Most of the compounds exhibit significant activity against <i style="mso-bidi-font-style: normal"><span style="font-size:15.0pt;mso-bidi-font-size:8.0pt;font-family: Fd298468-Identity-H;mso-bidi-font-family:Fd298468-Identity-H;color:#0C0C0C">Mycobacterium tuberculosis<span style="font-size:15.0pt;mso-bidi-font-size:8.0pt; font-family:Fd298468-Identity-H;mso-bidi-font-family:Fd298468-Identity-H; color:#0C0C0C"> <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt;font-family:Fd53207-Identity-H; mso-bidi-font-family:Fd53207-Identity-H;color:#0C0C0C">H37<span style="font-size:15.0pt;mso-bidi-font-size:8.0pt;font-family:Fd53207-Identity-H; mso-bidi-font-family:Fd53207-Identity-H;color:#0C0C0C"> <span style="font-size:15.0pt;mso-bidi-font-size: 8.0pt;font-family:Fd298468-Identity-H;mso-bidi-font-family:Fd298468-Identity-H; color:#0C0C0C">Rv<span style="font-size:15.0pt;mso-bidi-font-size: 8.0pt;font-family:Fd298468-Identity-H;mso-bidi-font-family:Fd298468-Identity-H; color:#0C0C0C"> <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt; font-family:Fd34462-Identity-H;mso-bidi-font-family:Fd34462-Identity-H; color:#0C0C0C">and MIC value is reported. Compounds <b style="mso-bidi-font-weight: normal"><span style="font-size:13.5pt;mso-bidi-font-size:6.5pt;font-family: Fd36020-Identity-H;mso-bidi-font-family:Fd36020-Identity-H;color:#0C0C0C">2c<span style="font-size:13.5pt;mso-bidi-font-size:6.5pt;font-family:Fd36020-Identity-H; mso-bidi-font-family:Fd36020-Identity-H;color:#0C0C0C">,<b style="mso-bidi-font-weight: normal">3c <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt; font-family:Fd34462-Identity-H;mso-bidi-font-family:Fd34462-Identity-H; color:#0C0C0C">and <span style="font-size:13.5pt; mso-bidi-font-size:6.5pt;font-family:Fd36020-Identity-H;mso-fareast-font-family: " times="" new="" roman";mso-bidi-font-family:fd36020-identity-h;color:#0c0c0c;="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">4d<span style="font-size:13.5pt;mso-bidi-font-size:6.5pt;font-family:Fd36020-Identity-H; mso-fareast-font-family:" times="" new="" roman";mso-bidi-font-family:fd36020-identity-h;="" color:#0c0c0c;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" ar-sa"=""> <span style="font-size:15.0pt;mso-bidi-font-size:8.0pt; font-family:Fd34462-Identity-H;mso-fareast-font-family:" times="" new="" roman";="" mso-bidi-font-family:fd34462-identity-h;color:#0c0c0c;mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">have been selected by Merck Incorporation USA for further pharmacological screening.</span

Synthesis of 2, 5-disubstituted 1, 3, 4-oxadiazoles as biologically active heterocycles

572-576<span style="font-size:12.0pt;font-family: " times="" new="" roman";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-in;mso-fareast-language:en-in;mso-bidi-language:ar-sa"="" lang="EN-IN">2-(8enzimidazol-2'-yl) benzoyl hydrazide 1 when condensed with aromatic acids in the presence of POCI3 afforded 2-aryl -5-[2'-benzimidazol-2"-yl) phenyl]-l, 3, 4-oxadiazoles 2a-o. The acid hydrazide 1 on cyclisation with CNBr yield 2-amino-5-[2'-(benzimidazol-2 "-yl-phenyl)- 1, 3, 4-oxadiazole 3 which on reaction with aryl sulphonyl chlorides and substituted benzoyl chloride give the corresponding sulphonaillides <b style="mso-bidi-font-weight: normal">4a-o and amides 5a-o, respectively. All the products have been evaluated in vitro for their antimicrobial activity against several microbes and antitubercular activity against Mycobacterium tuberculosis H37Rv.</span

Synthesis and anti-mildew activity of 5-(2-aroyl)aryloxymethyl-2-phenyl-1,3,4-oxadiazoles against downy mildew of pearl millet

A manipulatively simple, rapid, high-yielding and environmentally benign method for the integration of a heterocyclic ring, 1,3,4-oxadiazole, at the benzophenone nucleus has been achieved through intramolecular cyclization of substituted aroylaryloxyacetohydrazides to substituted 5-(2-aroyl)aryloxy-methyl-2-phenyl- 1,3,4-oxadiazoles under solventless `dry' conditions using montmorillonite K10 clay and microwave irradiation. A comparison is made of the microwave-accelerated reaction with conventional heating conditions. Certain of the derivatives tested showed significant anti-mildew activity against Sclerospora graminicola (Sacc) Schroeter, the downy mildew pathogen of pearl millet. (C) 2004 Society of Chemical Industry