Kinetic analysis of new multi-component reaction for the formation of Z-N-(3-(naphthalene-2-yl)-4-oxothiazolidine-2-ylidene) benzamide Mahdieh Darijani Sayyed Mostafa Habibi-Khorassani Mehdi Shahraki Reza Heydari Yaser Shahbakhsh Mahshid Hossaini 10.6084/m9.figshare.9916709.v1 https://tandf.figshare.com/articles/journal_contribution/Kinetic_analysis_of_new_multi-component_reaction_for_the_formation_of_Z-N-_3-_naphthalene-2-yl_-4-oxothiazolidine-2-ylidene_benzamide/9916709 <p>A new three-component reaction was studied kinetically among benzoyl isothiocyanate <b>(1)</b>, 1-naphthylamine <b>(2)</b>, and methyl bromoacetate <b>(3)</b> in the presence of triethylamine <b>(4)</b> as a catalyst, to yield Z-N-(3-(naphthalene-2-yl)-4-oxothiazolidine-2-ylidene) benzamide <b>(5)</b>. The overall reaction is a combination of two reactions; 1) reaction <b>a</b>, between <b>(1)</b> and <b>(2)</b> forming 1-benzoyl-3-(naphthalen-1-yl) thiourea <b>(P<sub>1</sub>)</b>; 2) reaction <b>b</b>, between <b>(P<sub>1</sub>), (3)</b> and <b>(4)</b> to form the product <b>(5)</b>. The rate of reaction <b>a</b>, (<math><msubsup><mrow><mi>k</mi></mrow><mrow><mi>o</mi><mi>b</mi><mi>s</mi></mrow><mrow><mi>a</mi></mrow></msubsup><mo>=</mo><mn>66.49</mn><mi> </mi><mrow><mi>M</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow><mi> </mi><mrow><mi>m</mi><mi>i</mi><mi>n</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></math>) was more than the reaction <b>b</b> (<math><msubsup><mrow><mi>k</mi></mrow><mrow><mi>o</mi><mi>b</mi><mi>s</mi></mrow><mrow><mi>b</mi></mrow></msubsup><mo>=</mo><mn>2.9</mn><mi> </mi><mrow><mi>M</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow><mi> </mi><mrow><mi>m</mi><mi>i</mi><mi>n</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow><mo>)</mo></math>, in acetonitrile solvent at 25 °C. A mechanism was proposed involving step<sub>1</sub> (<math><msubsup><mrow><mi>k</mi></mrow><mrow><mi>o</mi><mi>b</mi><mi>s</mi></mrow><mrow><mi>a</mi></mrow></msubsup></math>), step<sub>2</sub> (<i>k<sub>2</sub> </i>), step<sub>3</sub> (<i>k<sub>3</sub> </i>) and step<sub>4</sub> (<i>k<sub>4</sub> </i>). Substituent effects with electron-withdrawing groups on para-position of benzoyl isothiocyanate <b>(1)</b> increased the rate constants of <math><msubsup><mrow><mi>k</mi></mrow><mrow><mi>o</mi><mi>b</mi><mi>s</mi></mrow><mrow><mi>a</mi></mrow></msubsup></math> and <i>k<sub>2</sub> </i>. The large negative entropy, ΔS<sup>‡</sup>, values in reactions <b>a</b>, and <b>b</b> are in agreement with step<sub>1</sub> (<math><msubsup><mrow><mi>k</mi></mrow><mrow><mi>o</mi><mi>b</mi><mi>s</mi></mrow><mrow><mi>a</mi></mrow></msubsup></math>) and step<sub>2</sub> (<i>k</i> <sub>2</sub>), an associative mechanism with a negative ΔS<sup>‡</sup>. The sum of these observations proved that the rate-determining step (RDS) is step<sub>2</sub>. It seems that the most important steps in the reaction mechanism are step<sub>1</sub> (<math><msubsup><mrow><mi>k</mi></mrow><mrow><mi>o</mi><mi>b</mi><mi>s</mi></mrow><mrow><mi>a</mi></mrow></msubsup></math>) and step<sub>2</sub> <i>(k<sub>2</sub> </i>), which strongly control the reaction process. The kinetics and mechanism of these reactions were assessed by UV–vis spectrophotometry.</p> 2019-09-28 10:06:36 Thiazole kinetics and mechanism multi-component UV-vis spectrophotometry technique