ANYL 87 |
| In this work selective online derivatisation using phenyltrimethylammonium iodide (PTMA-I) ion-pair reagent has been achieved for acids, phenols and carboxyamides of naphthalene. It was observed that PTMA-I selectively methylated –COOH functional group in presence of –OH and –CONH2. Further the addition of KOH (4x10-4M) showed selective methylation of –COOH and –OH functional groups, leaving –CONH2 unchanged. But with further increase in KOH (4x10-1M) all the three functional groups were methylated with good efficiency. In presence of excess of KOH (4x10-1M), selective dimethylated carboxyamide derivative of naphthalene was obtained. This study was monitored by EI-MS, which was followed by CH4 CI-MS for further confirmation of the products. The use of tetramethylammonium hydroxide (TMA-OH) as derivatising ion-pair reagent was found to be nonselective in our study as it methylated all the three functional groups of naphthalene. It was observed that the combination of PTMA-I and KOH plays an important role in the chemoselective methylation of the compounds and the plausible mechanism has been proposed. This methodology was successfully applied to naphthalene derivatives and might be further extended to range of compounds owing to its potential applicability for selectivity in terms of functional groups. |
|
General Papers
7:00 PM-9:00 PM, Sunday, 10 September 2006 Moscone Center -- Hall D, Poster
Division of Analytical Chemistry |