{"id":25313,"date":"2022-08-07T11:12:54","date_gmt":"2022-08-07T10:12:54","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=25313"},"modified":"2022-09-11T06:16:18","modified_gmt":"2022-09-11T05:16:18","slug":"unexpected-isomerization-of-oxetane-carboxylic-acids-a-first-look-at-the-mechanism","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313","title":{"rendered":"Unexpected Isomerization of Oxetane-Carboxylic Acids &#8211; a first look at the mechanism"},"content":{"rendered":"<div class=\"kcite-section\" kcite-section-id=\"25313\">\n<p>Derek Lowe&#8217;s blog has a recent post entitled <a href=\"https:\/\/www.science.org\/content\/blog-post\/downside-oxetane-acids\">A Downside to Oxetane Acids<\/a> which picks up on a recent article<span id=\"cite_ITEM-25313-0\" name=\"citation\"><a href=\"#ITEM-25313-0\">[1]<\/a><\/span> describing how these acids are unexpectedly unstable, isomerising to a lactone at a significant rate without the apparent need for any catalyst. This is important because these types of compound occur frequently in the medicinal chemistry literature.<\/p>\n<p><a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane.svg\"><img decoding=\"async\" class=\"alignnone size-full wp-image-25316\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane.svg\" alt=\"\" width=\"450\" \/><\/a><\/p>\n<p>The isomerism is reported to occur quite slowly but significantly in the pure substance, being complete in around a year. Any uncatalysed mechanism must comprise a proton transfer to the oxygen of the oxetane followed by an Sn2 displacement at the methylene group in the protonated oxetane. This could be stepwise or concerted (the latter shown with arrows above). To determine the answer,\u00a0an \u03c9B97XD\/Def2-TZVPP\/SCRF=chloroform calculation was performed (FAIR data DOI: <a href=\"https:\/\/doi.org\/10.14469\/hpc\/10820\">10.14469\/hpc\/10820<\/a>) which clearly shows a concerted reaction, albeit one in which a proton transfer (IRC ~-1.5) preceeds the Sn2 displacement with retention of configuration! The transition state appears to have no biradical character. The activation free energy is\u00a0\u0394G<sup>\u2021<\/sup> 49.9 kcal\/mol and the reaction is clearly exoenergic.<\/p>\n<p><img decoding=\"async\" class=\"alignnone size-medium wp-image-25325\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetanes.gif\" alt=\"\" width=\"350\" \/><\/p>\n<p><a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane_tot_ener.svg\"><img decoding=\"async\" class=\"alignnone size-full wp-image-25320\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane_tot_ener.svg\" alt=\"\" width=\"540\" \/><\/a><br \/>\n<a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane_rms_gnorm.svg\"><img decoding=\"async\" class=\"alignnone size-full wp-image-25323\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane_rms_gnorm.svg\" alt=\"\" width=\"540\" \/><\/a><\/p>\n<p>The dipole moment response shows that the proton transfer induces a larger dipole moment, which then reduces as the Sn2 reaction occurs.<\/p>\n<p><a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane_dipole.svg\"><img decoding=\"async\" class=\"alignnone size-full wp-image-25324\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane_dipole.svg\" alt=\"\" width=\"540\" \/><\/a><\/p>\n<p>The calculated free energy barrier of ~50 kcal\/mol is ~15-20 kcal\/mol too high to occur thermally and so the observed reaction either occurs <em>via<\/em> a different mechanism, perhaps bimolecular in which one molecule of the oxetane-carboxylic acid acts as a catalyst for a second molecule to rearrange, or one in which a stronger external acid catalyst operates, such as traces of other acid in the system. Exploring the sensitivity to substituents on the oxetane ring (CH<sub>3<\/sub>, CF<sub>3<\/sub>, etc) might also cast light on the mechanism, as might testing the stereochemistry of the two carbons next to the oxygen of the oxetane; do they retain, invert or scramble the configuration at these two centres?<\/p>\n<hr \/>\n<p>DOI: 10.14469\/hpc\/10863 and <a href=\"http:\/\/doi.org\/10.14469\/hpc\/10862\" rel=\"noopener\" target=\"_blank\">10.14469\/hpc\/10862<\/a><\/p>\n<hr \/>\n<h2>References<\/h2>\n    <ol class=\"kcite-bibliography csl-bib-body\"><li id=\"ITEM-25313-0\">B. Chalyk, A. Grynyova, K. Filimonova, T.V. Rudenko, D. Dibchak, and P.K. Mykhailiuk, \"Unexpected Isomerization of Oxetane-Carboxylic Acids\", <i>Organic Letters<\/i>, vol. 24, pp. 4722-4728, 2022. <a href=\"https:\/\/doi.org\/10.1021\/acs.orglett.2c01402\">https:\/\/doi.org\/10.1021\/acs.orglett.2c01402<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> <!-- kcite-section 25313 -->","protected":false},"excerpt":{"rendered":"<p>Derek Lowe&#8217;s blog has a recent post entitled A Downside to Oxetane Acids which picks up on a recent article describing how these acids are unexpectedly unstable, isomerising to a lactone at a significant rate without the apparent need for any catalyst. This is important because these types of compound occur frequently in the medicinal [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":5,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1086],"tags":[],"ppma_author":[2661],"class_list":["post-25313","post","type-post","status-publish","format-standard","hentry","category-reaction-mechanism-2"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.8 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Unexpected Isomerization of Oxetane-Carboxylic Acids - a first look at the mechanism - Henry Rzepa&#039;s Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Unexpected Isomerization of Oxetane-Carboxylic Acids - a first look at the mechanism - Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"og:description\" content=\"Derek Lowe&#8217;s blog has a recent post entitled A Downside to Oxetane Acids which picks up on a recent article describing how these acids are unexpectedly unstable, isomerising to a lactone at a significant rate without the apparent need for any catalyst. This is important because these types of compound occur frequently in the medicinal [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"article:published_time\" content=\"2022-08-07T10:12:54+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2022-09-11T05:16:18+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane.svg\" \/>\n<meta name=\"author\" content=\"Henry Rzepa\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Henry Rzepa\" \/>\n\t<meta name=\"twitter:label2\" content=\"Estimated reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"2 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Unexpected Isomerization of Oxetane-Carboxylic Acids - a first look at the mechanism - Henry Rzepa&#039;s Blog","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313","og_locale":"en_GB","og_type":"article","og_title":"Unexpected Isomerization of Oxetane-Carboxylic Acids - a first look at the mechanism - Henry Rzepa&#039;s Blog","og_description":"Derek Lowe&#8217;s blog has a recent post entitled A Downside to Oxetane Acids which picks up on a recent article describing how these acids are unexpectedly unstable, isomerising to a lactone at a significant rate without the apparent need for any catalyst. This is important because these types of compound occur frequently in the medicinal [&hellip;]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313","og_site_name":"Henry Rzepa&#039;s Blog","article_published_time":"2022-08-07T10:12:54+00:00","article_modified_time":"2022-09-11T05:16:18+00:00","og_image":[{"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane.svg","type":"","width":"","height":""}],"author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"2 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"Unexpected Isomerization of Oxetane-Carboxylic Acids &#8211; a first look at the mechanism","datePublished":"2022-08-07T10:12:54+00:00","dateModified":"2022-09-11T05:16:18+00:00","mainEntityOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313"},"wordCount":338,"commentCount":4,"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313#primaryimage"},"thumbnailUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane.svg","articleSection":["reaction mechanism"],"inLanguage":"en-GB","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313","name":"Unexpected Isomerization of Oxetane-Carboxylic Acids - a first look at the mechanism - Henry Rzepa&#039;s Blog","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313#primaryimage"},"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313#primaryimage"},"thumbnailUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane.svg","datePublished":"2022-08-07T10:12:54+00:00","dateModified":"2022-09-11T05:16:18+00:00","author":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"breadcrumb":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313#primaryimage","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane.svg","contentUrl":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/oxetane.svg"},{"@type":"BreadcrumbList","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25313#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog"},{"@type":"ListItem","position":2,"name":"Unexpected Isomerization of Oxetane-Carboxylic Acids &#8211; a first look at the mechanism"}]},{"@type":"WebSite","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/","name":"Henry Rzepa&#039;s Blog","description":"Chemistry with a twist","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-GB"},{"@type":"Person","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281","name":"Henry Rzepa","image":{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g370be3a7397865e4fd161aefeb0a5a85","url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","caption":"Henry Rzepa"},"description":"Henry Rzepa is Emeritus Professor of Computational Chemistry at Imperial College London.","sameAs":["https:\/\/orcid.org\/0000-0002-8635-8390"],"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?author=1"}]}},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/pDef7-6Ah","jetpack-related-posts":[{"id":25415,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25415","url_meta":{"origin":25313,"position":0},"title":"Unexpected Isomerization of Oxetane-Carboxylic Acids \u2013 substrate design.","author":"Henry Rzepa","date":"August 14, 2022","format":false,"excerpt":"Having established a viable model for the unexpected isomerism of oxetane carboxylic acids to lactones, and taken a look at a variation in the proton transfer catalyst needed to accomplish the transformation, I now investigate the substrate itself. R' is set to have three values, R'=H (the original substituent), R'=\u2026","rel":"","context":"In &quot;reaction mechanism&quot;","block_context":{"text":"reaction mechanism","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1086"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":25338,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25338","url_meta":{"origin":25313,"position":1},"title":"Unexpected Isomerization of Oxetane-Carboxylic Acids \u2013 a viable mechanism","author":"Henry Rzepa","date":"August 12, 2022","format":false,"excerpt":"In the previous post, I looked at the intramolecular rearrangement of the oxetane carboxylic acid to a lactone, finding the barrier to the Sn2 reaction with retention was unfeasibly high. Here I explore alternatives. This first attempt uses a second molecule of a carboxylic acid (modelled as formic acid for\u2026","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/Rtn.gif?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/Rtn.gif?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/Rtn.gif?resize=525%2C300&ssl=1 1.5x"},"classes":[]},{"id":25391,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25391","url_meta":{"origin":25313,"position":2},"title":"Unexpected Isomerization of Oxetane-Carboxylic Acids \u2013 catalyst design.","author":"Henry Rzepa","date":"August 13, 2022","format":false,"excerpt":"Previously, a mechanism with a reasonable predicted energy was modelled for the isomerisation of an oxetane carboxylic acid to a lactone by using two further molecules of acid to transfer the proton and in the process encouraging an Sn2 reaction with inversion to open the oxetane ring. We are now\u2026","rel":"","context":"In &quot;reaction mechanism&quot;","block_context":{"text":"reaction mechanism","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1086"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":25439,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=25439","url_meta":{"origin":25313,"position":3},"title":"Unexpected Isomerization of Oxetane-Carboxylic Acids \u2013 an alternative autocatalytic mechanism evaluated.","author":"Henry Rzepa","date":"August 17, 2022","format":false,"excerpt":"Previously, I looked at autocatalytic mechanisms where the carboxyl group of an oxetane-carboxylic acid could catalyse its transformation to a lactone, finding that a chain of two such groups were required to achieve the result. Here I look at an alternative mode where the oxetane-carboxylate itself acts as the transfer\u2026","rel":"","context":"In &quot;reaction mechanism&quot;","block_context":{"text":"reaction mechanism","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1086"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2022\/08\/saddle.gif?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":3802,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=3802","url_meta":{"origin":25313,"position":4},"title":"Why are \u03b1-helices in proteins mostly right handed?","author":"Henry Rzepa","date":"April 9, 2011","format":false,"excerpt":"Understanding why and how proteins fold continues to be a grand challenge in science. I have described how Wrinch in 1936 made a bold proposal for the mechanism, which however flew in the face of much of then known chemistry. Linus Pauling took most of the credit (and a Nobel\u2026","rel":"","context":"In &quot;Interesting chemistry&quot;","block_context":{"text":"Interesting chemistry","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=4"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/04\/left-n.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":13899,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=13899","url_meta":{"origin":25313,"position":5},"title":"The mechanism of borohydride reductions. Part 1: ethanal.","author":"Henry Rzepa","date":"April 12, 2015","format":false,"excerpt":"Sodium borohydride is the tamer cousin of lithium aluminium hydride (LAH). It is used in aqueous solution to e.g. reduce aldehydes and ketones, but it leaves acids, amides and esters alone. Here I start an exploration of why it is such a different reducing agent. Initially, I am using Li,\u2026","rel":"","context":"In &quot;reaction mechanism&quot;","block_context":{"text":"reaction mechanism","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1086"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]}],"jetpack_likes_enabled":false,"authors":[{"term_id":2661,"user_id":1,"is_guest":0,"slug":"admin","display_name":"Henry Rzepa","avatar_url":"https:\/\/secure.gravatar.com\/avatar\/897b6740f7f599bca7942cdf7d7914af5988937ae0e3869ab09aebb87f26a731?s=96&d=blank&r=g","author_category":"1","first_name":"Henry","last_name":"Rzepa","user_url":"https:\/\/orcid.org\/0000-0002-8635-8390","job_title":"","description":"Henry Rzepa is Emeritus Professor of Computational Chemistry at Imperial College London."}],"_links":{"self":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/25313","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=25313"}],"version-history":[{"count":22,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/25313\/revisions"}],"predecessor-version":[{"id":25438,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/25313\/revisions\/25438"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=25313"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25313"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25313"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=25313"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}