Please use this identifier to cite or link to this item: http://nopr.niscair.res.in/handle/123456789/13218
Title: Syntheses of L-dopa glycosides using glucosidases
Authors: Vadivelan, Ganesan
Divakar, Soundar
Keywords: L-Dopa
Glycosides
Glycosylation
Amyloglucosidase
Immobilized
<img src='/image/spc_char/beta.gif' border=0>-glucosidase
Regioselectivity
Issue Date: Dec-2011
Publisher: NISCAIR-CSIR, India
Abstract: <span style="mso-ansi-language:PT-BR" lang="PT-BR">Syntheses of l<span style="mso-ansi-language:PT-BR" lang="PT-BR">-dopa <b>1</b> glycosides <b>13-22</b> with d<span style="mso-ansi-language:PT-BR" lang="PT-BR">-glucose <b>2</b>, d<span style="mso-ansi-language:PT-BR" lang="PT-BR">-galactose <b>3</b>, d<span style="mso-ansi-language: PT-BR" lang="PT-BR">-mannose <b>4</b>, d<span style="mso-ansi-language:PT-BR" lang="PT-BR">-fructose <b style="mso-bidi-font-weight: normal">5,</b> d<span style="mso-ansi-language:PT-BR" lang="PT-BR">-ribose 6, d<span style="mso-ansi-language: PT-BR" lang="PT-BR">-arabinose <b style="mso-bidi-font-weight:normal">7</b>, lactose <b style="mso-bidi-font-weight:normal">8</b>, maltose <b style="mso-bidi-font-weight: normal">9</b>, sucrose <b style="mso-bidi-font-weight:normal">10</b>, and d<span style="mso-ansi-language:PT-BR" lang="PT-BR">-mannitol <b>11</b> have been carried out using amyloglucosidase from <i>Rhizopus</i> mold and <span style="font-family:Symbol;mso-ascii-font-family:" times="" new="" roman";mso-hansi-font-family:="" "times="" roman";mso-char-type:symbol;mso-symbol-font-family:symbol"="" lang="EN-GB">b<span style="mso-ansi-language:PT-BR" lang="PT-BR">-glucosidase isolated from sweet almond and entrapped onto calcium alginate beads. Invariably, l-dopa gives very low to moderate yields of glycosides <b>13-22 </b><span style="mso-bidi-font-weight:bold">at 3.3 – 57.6% range. Only mono glycosylated products are detected through glycosylation/arylation at the 3<sup>rd</sup> or 4<sup>th</sup> OH positions of l-dopa <b>1</b><span style="mso-bidi-font-weight:bold">. Arylation occurs at 6-O-positions with d-glucose <b style="mso-bidi-font-weight:normal">2</b> and d-galactose <b style="mso-bidi-font-weight:normal">3</b>. Amyloglucosidase catalyzes the reaction with all ten carbohydrate molecules employed with the exception of d-sorbitol. Regio-selectivity is observed in case of d-mannose <b>4</b> to give 4-<i>O</i>-C1α, d-fructose <b style="mso-bidi-font-weight:normal">5</b> to give 4-O-2-O, ribose <b style="mso-bidi-font-weight:normal">6</b> to give 4-O-C1α, maltose <b style="mso-bidi-font-weight:normal">9</b> to give 4-O-C1α, sucrose <b style="mso-bidi-font-weight:normal">10</b> to give 4-O-6--O, and d-mannitol <b style="mso-bidi-font-weight: normal">11</b> to give 4-O-1-O. Immobilised <span style="font-family:Symbol;mso-ascii-font-family:" times="" new="" roman";mso-hansi-font-family:="" "times="" roman";mso-char-type:symbol;mso-symbol-font-family:symbol"="" lang="EN-GB">b-glucosidase does not show any selectivity and catalyzed reactions with d<span style="mso-ansi-language:PT-BR" lang="PT-BR">-glucose <b>2</b>, d<span style="mso-ansi-language: PT-BR" lang="PT-BR">-galactose <b>3, </b>d<span style="mso-ansi-language:PT-BR" lang="PT-BR">-ribose 6 and lactose <b style="mso-bidi-font-weight:normal">8</b>. </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
Description: 1779-1785
URI: http://hdl.handle.net/123456789/13218
ISSN: 0975-0983(Online); 0376-4699(Print)
Appears in Collections:IJC-B Vol.50B(12) December 2011]

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