<span style="font-size:12.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-ansi-language: EN-IN;mso-fareast-language:EN-IN;mso-bidi-language:AR-SA" lang="EN-IN">Synthesis of 3-ethylphthalides and their conversion to 3-methyl-3,4-dihydro-isocoumarins: Synthesis of (±)-5-methylmellein.</span>

Abstract

<i><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">Ortho-</span></i><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;mso-bidi-font-style:italic"="" lang="EN-IN">directed<i> </i><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">lithiation of <i style="mso-bidi-font-style:normal">N</i>-methylbenzamides <b style="mso-bidi-font-weight:normal">1a-f</b> with <i style="mso-bidi-font-style: normal">n</i>-BuLi in either/THF followed by alkylation with propanal gives 3- ethylphthalides <b style="mso-bidi-font-weight:normal">2a-f</b> which on treatment with conc. H₂SO₄ or AlCI₃ afford 3-methyl-3,4-dihydroisocoumarins <b style="mso-bidi-font-weight:normal">3a-f</b>.</span></span>