Pharmaceuticals (Jul 2012)
Synthesis, Reactions and Evaluation of the Antimicrobial Activity of Some 4-(<em>p</em>-Halophenyl)-4<em>H</em>-naphthopyran, Pyranopyrimidine and Pyranotriazolopyrimidine Derivatives
Abstract
A series of naphthopyran derivatives <strong>3a–f</strong> were prepared. Reaction of <em>2-</em>amino-4-(<em>p</em>-chlorophenyl)-7-methoxy-4<em>H</em>-naphtho[2,1-<em>b</em>]pyran-3-carbonitrile (<strong>3b</strong>) with Ac<sub>2</sub>O afforded two products, 2-acetylamino-7-methoxy-4-(<em>p</em>-chlorophenyl)-4<em>H</em>-naphtho-[2,1-<em>b</em>]pyran-3-carbonitrile (<strong>4</strong>) and 10,11-dihydro-3-methoxy-9-methyl-12-(<em>p</em>-chloro-phenyl)-12<em>H</em>-naphtho[2,1-<em>b</em>]pyran[2,3-<em>d</em>]pyrimidine-11-one (<strong>5</strong>) and treatment of <strong>3b</strong> with benzoyl chloride gave the pyranopyrimidin-11-one derivative <strong>6</strong>. While treatment of <strong>3b</strong> with formamide afforded 11-amino-3-methoxy-12-(<em>p</em>-chlorophenyl)-12<em>H</em>-naphtho[2,1-<em>b</em>]pyrano[2,3-<em>d</em>]pyrimidine (<strong>7</strong>). Reaction of <strong>3b</strong> with triethyl orthoformate gave the corresponding 2-ethoxymethyleneamino-7-methoxy-4-(<em>p</em>-chlorophenyl)-4<em>H</em>-naphtho-[2,1-<em>b</em>]pyran-3-carbonitrile (<strong>8</strong>). Hydrazinolysis of <strong>8</strong> in EtOH at room temperature yielded 10-amino-10,11-dihydro-11-imino-3-methoxy-12-(<em>p</em>-chlorophenyl)-12<em>H</em>-naphtho[2,1-b]pyrano-[2,3-d]pyrimidine (<strong>9</strong>), while aminolysis of <strong>8</strong> with methylamine or dimethylamine gave the corresponding pyranopyrimidine and <em>N,N</em>-dimethylaminomethylene derivatives <strong>10</strong> and <strong>11</strong>. Condensation of <strong>9</strong> with some carboxylic acid derivatives afforded triazolopyrimidine derivatives <strong>12–16</strong>, while reaction of <strong>9</strong> with benzaldehyde gave 10-benzalamino-10,11-dihydro-11-imino-3-methoxy-12-(<em>p</em>-chlorophenyl)12<em>H</em>-naphtho[2,1-<em>b</em>]pyrano[2,3-<em>d</em>]pyrimidine (<strong>17</strong>). The structures of the newly synthesized compounds were confirmed by spectral data. The synthesized compounds were also screened for their antimicrobial activity.
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