Aldohexoses A and B both undergo Ruff degradation to give aldopentose C. On treatment with warm nitric acid, aldopentose C gives an optically active aldaric acid. B also
reacts with warm nitric acid to give an optically active aldaric acid, but A reacts to give
an optically inactive aldaric acid. Aldopentose C is degraded to aldotetrose D, which
gives optically active tartaric acid when it is treated with nitric acid. Aldotetrose D is
degraded to (+)@glyceraldehyde. Deduce the structures of sugars A, B, C, and D, and use
Figure 23-3 to determine the correct names of these sugars.<\/p>\n\n\n\n
The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n Based on the given information, we can deduce the structures of sugars A, B, C, and D step by step using the information about the reactions and their outcomes.<\/p>\n\n\n\n Ruff degradation is a reaction where aldoses (like hexoses) are converted to pentoses by the oxidative cleavage of the aldehyde group, followed by a decarboxylation reaction. The result is the formation of a pentose sugar. Aldohexoses A and B both undergo Ruff degradation to give the same aldopentose C. Therefore, both A and B are aldoses, and they must be epimers<\/strong> (sugars that differ in the configuration of only one stereocenter).<\/p>\n\n\n\n Aldopentose C reacts with warm nitric acid to give an optically active aldaric acid. Aldaric acid is formed by the oxidation of both the aldehyde group and the hydroxyl group on the terminal carbon, creating a dicarboxylic acid. The fact that the aldaric acid is optically active indicates that aldopentose C is a chiral<\/strong> molecule (it has at least one asymmetric center). This suggests that C is not<\/strong> a meso compound.<\/p>\n\n\n\n Aldopentose C is degraded to aldotetrose D<\/strong>. This suggests that C is a pentose<\/strong> sugar, and it undergoes further oxidation under nitric acid treatment. Tetrose D gives optically active tartaric acid<\/strong> upon treatment with nitric acid, indicating that D is also chiral<\/strong> and likely a sugar with two chiral centers.<\/p>\n\n\n\n Aldotetrose D is further degraded to (+)-glyceraldehyde<\/strong>. This suggests that D is a tetrose<\/strong> with a chiral center at its second carbon. The structure of D corresponds to D-erythrose<\/strong>.<\/p>\n\n\n\n These deductions are supported by known sugar structures and their reactions in Ruff degradation and oxidation processes.<\/p>\n","protected":false},"excerpt":{"rendered":" Aldohexoses A and B both undergo Ruff degradation to give aldopentose C. On treatment with warm nitric acid, aldopentose C gives an optically active aldaric acid. B alsoreacts with warm nitric acid to give an optically active aldaric acid, but A reacts to givean optically inactive aldaric acid. Aldopentose C is degraded to aldotetrose D, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","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":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"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-opacity":"","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-opacity":"","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-opacity":"","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-opacity":"","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-opacity":"","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-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-188206","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/188206","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=188206"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/188206\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=188206"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=188206"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=188206"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Step 1: Understand the Ruff degradation<\/h3>\n\n\n\n
Step 2: Reaction of aldopentose C with warm nitric acid<\/h3>\n\n\n\n
Step 3: Reactions of A and B with nitric acid<\/h3>\n\n\n\n
\n
Step 4: Aldopentose C and its degradation<\/h3>\n\n\n\n
Step 5: Degradation of D to glyceraldehyde<\/h3>\n\n\n\n
Summary of Structures<\/h3>\n\n\n\n
\n