{"id":496,"date":"2024-01-30T14:56:01","date_gmt":"2024-01-30T14:56:01","guid":{"rendered":"https:\/\/chemtry.in\/?p=496"},"modified":"2024-02-03T08:00:50","modified_gmt":"2024-02-03T08:00:50","slug":"protection-of-carbohydrate-cyclic-acetal-formation-in-reducing-sugars-and-glycosides","status":"publish","type":"post","link":"https:\/\/chemtry.in\/?p=496","title":{"rendered":"Protection of Carbohydrate &#8211; Cyclic Acetal Formation in Reducing Sugars and Glycosides"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"496\" class=\"elementor elementor-496\" data-elementor-post-type=\"post\">\n\t\t\t\t\t\t<section class=\"elementor-section elementor-top-section elementor-element elementor-element-f5a4f04 elementor-section-boxed elementor-section-height-default elementor-section-height-default\" data-id=\"f5a4f04\" data-element_type=\"section\">\n\t\t\t\t\t\t<div class=\"elementor-container elementor-column-gap-default\">\n\t\t\t\t\t<div class=\"elementor-column elementor-col-100 elementor-top-column elementor-element elementor-element-bfc6053\" data-id=\"bfc6053\" data-element_type=\"column\">\n\t\t\t<div class=\"elementor-widget-wrap elementor-element-populated\">\n\t\t\t\t\t\t<div class=\"elementor-element elementor-element-4f87ce7 elementor-widget elementor-widget-heading\" data-id=\"4f87ce7\" data-element_type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Cyclic Acetal Formation on Reducing Sugars<\/h2>\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-4b2e1e0 elementor-widget elementor-widget-text-editor\" data-id=\"4b2e1e0\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<p>Frequently results in the production of a number of products via the formation of acetals on both the furanose and pyranose isomers.<\/p><p>&#8211; Leading references<\/p><ul><li>Gelas, J.<em> Adv. Carbohydrate. Chem. Biochem.,<\/em> <strong>1981<\/strong>, 39, 71-156.<\/li><li>de Belder, A. N. <em>Adv. Carbohydr. Chem. Biochem.,<\/em> <strong>1977<\/strong>, 34, 179-241.<\/li><li>de Belder, A. N. <em>Adv. Carbohydr. Chem. Biochem.,<\/em> <strong>1965<\/strong>, 20, 219-302.<\/li><li>Brady Jr., R. F.\u00a0<em>Adv. Carbohydr. Chem. Biochem.,<\/em> <strong>1971<\/strong>, 26, 197-278.<\/li><li>Close, D. M. <em>Chem. Rev.<\/em>, <strong>1979<\/strong>, 79, 491 -513.<\/li><\/ul><p>Most useful derivatives are isopropylidene acetals.<\/p><ul><li>In general the sugar will add as many equivalents of acetone as possible; dictated by relative stereochemistry of the hydroxyl groups on the sugar.<\/li><li>Formation typically involves the suspension or dissolution of the sugar in acetone or dimethoxypropane followed by the addition of the acid. Solution becomes homogenous as it reacts. This method leads to the thermodynamic products.<\/li><li>Kinetic products can be obtained by using a cosolvent (DMF, CH3CN) and 1-4 equivalents of either dimethoxypropane or 2-methoxypropane or 2-methoxypropene as the isopropylidenation reagent.<\/li><\/ul><p>Formation of thermodynamic isopropylidene products with glucose, mannose and galactose.<\/p><p><strong>Glucose<\/strong><\/p><ul><li><em>Methods in Carbohydrate Chemistry<\/em>, Volume 2, page 318.<\/li><li>Pyranose forms of the sugar predominate at equilibrium and the kinetic product is the 4,6-isopropylidene.<\/li><\/ul>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-b9fc993 elementor-widget elementor-widget-image\" data-id=\"b9fc993\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"378\" height=\"114\" src=\"https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-01-30-at-20.17.14.png\" class=\"attachment-large size-large wp-image-500\" alt=\"\" srcset=\"https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-01-30-at-20.17.14.png 378w, https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-01-30-at-20.17.14-300x90.png 300w\" sizes=\"(max-width: 378px) 100vw, 378px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-947f119 elementor-widget elementor-widget-text-editor\" data-id=\"947f119\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<ul><li>Due to axial CH3 in the dioxane, rearrangement is favoured; however , all 2\u00b0 OH groups on the pyranose from are trans and so acetal migration via the intermediate below does not occur.<\/li><\/ul>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-f6bc717 elementor-widget elementor-widget-image\" data-id=\"f6bc717\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"468\" height=\"257\" src=\"https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-02-01-at-23.27.37.png\" class=\"attachment-large size-large wp-image-505\" alt=\"\" srcset=\"https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-02-01-at-23.27.37.png 468w, https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-02-01-at-23.27.37-300x165.png 300w\" sizes=\"(max-width: 468px) 100vw, 468px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-80d3d74 elementor-widget elementor-widget-text-editor\" data-id=\"80d3d74\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<ul><li>Instead, the ring isomerizes to the furanose form as below giving the 5,6-isopropylidene.<\/li><\/ul>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-9425240 elementor-widget elementor-widget-image\" data-id=\"9425240\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"463\" height=\"314\" src=\"https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-02-01-at-23.32.24.png\" class=\"attachment-large size-large wp-image-506\" alt=\"\" srcset=\"https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-02-01-at-23.32.24.png 463w, https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-02-01-at-23.32.24-300x203.png 300w\" sizes=\"(max-width: 463px) 100vw, 463px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-2d34097 elementor-widget elementor-widget-text-editor\" data-id=\"2d34097\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t<ul><li>Anomerization and then acetonation gives the product.\u00a0<\/li><\/ul>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-6efbd50 elementor-widget elementor-widget-image\" data-id=\"6efbd50\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t<img loading=\"lazy\" decoding=\"async\" width=\"497\" height=\"219\" src=\"https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-02-01-at-23.34.24.png\" class=\"attachment-large size-large wp-image-507\" alt=\"\" srcset=\"https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-02-01-at-23.34.24.png 497w, https:\/\/chemtry.in\/wp-content\/uploads\/2024\/01\/Screenshot-2024-02-01-at-23.34.24-300x132.png 300w\" sizes=\"(max-width: 497px) 100vw, 497px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Cyclic Acetal Formation on Reducing Sugars Frequently results in the production of a number of products via the formation of acetals on both the furanose and pyranose isomers. &#8211; Leading references Gelas, J. Adv. Carbohydrate. Chem. Biochem., 1981, 39, 71-156. de Belder, A. N. Adv. Carbohydr. Chem. Biochem., 1977, 34, 179-241. de Belder, A. N. &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"\" href=\"https:\/\/chemtry.in\/?p=496\"> <span class=\"screen-reader-text\">Protection of Carbohydrate &#8211; Cyclic Acetal Formation in Reducing Sugars and Glycosides<\/span> Read More &raquo;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[2],"tags":[],"_links":{"self":[{"href":"https:\/\/chemtry.in\/index.php?rest_route=\/wp\/v2\/posts\/496"}],"collection":[{"href":"https:\/\/chemtry.in\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chemtry.in\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chemtry.in\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/chemtry.in\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=496"}],"version-history":[{"count":9,"href":"https:\/\/chemtry.in\/index.php?rest_route=\/wp\/v2\/posts\/496\/revisions"}],"predecessor-version":[{"id":511,"href":"https:\/\/chemtry.in\/index.php?rest_route=\/wp\/v2\/posts\/496\/revisions\/511"}],"wp:attachment":[{"href":"https:\/\/chemtry.in\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=496"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chemtry.in\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=496"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chemtry.in\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=496"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}