{"id":10184,"date":"2013-04-14T19:26:04","date_gmt":"2013-04-14T18:26:04","guid":{"rendered":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=10184"},"modified":"2014-11-06T11:25:13","modified_gmt":"2014-11-06T11:25:13","slug":"intermediates-in-oxime-formation-from-hydroxylamine-and-propanone-now-you-see-them-now-you-dont","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184","title":{"rendered":"Intermediates in oxime formation from hydroxylamine and propanone: now you see them, now you don’t."},"content":{"rendered":"
\n

A recent theme here has been to subject to scrutiny well-known mechanisms supposedly involving intermediates. These transients can often involve the creation\/annihilation of charge separation resulting from \u00a0proton transfers, something that a cyclic mechanism can avoid. Here I revisit the formation of an oxime from hydroxylamine and propanone, but with one change. In the earlier post<\/a>, I used two molecules of water to achieve the desired proton transfer. Now I look to see what effect replacing those two water molecules by a guanidine<\/strong> has.\"NH2OH+Guanidine\"<\/p>\n

As become evident when I looked at ester hydrolysis, water is a very weak acid\/conjugate base, and so the barriers for reactions mediated by pure water tend to be high; catalysis by pure water in other words is slow. The barriers are lowered considerably if the two water molecules are replaced by a species better able to stabilise a (charge separated) intermediate, such as guanidine. So here I re-investigate the oxime mechanism with this base (\u03c9B97XD\/6-311G(d,p)\/SCRF=water).<\/p>\n\n\n\n
\"oxime-2H2O-O\"[1]<\/a><\/span><\/td>\n\"oxime-guan-O\"[2]<\/a><\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The IRC profile for the 2H2<\/sub>O catalysed O-nucleophilic addition (red arrows above<\/span>) reveals a concerted and largely synchronous addition combined with proton transfers along the water chain. Look at the difference when guanidine is involved. The barrier drops from ~24 kcal\/mol (a very slow reaction at room temperature) to ~11 kcal\/mol<\/a> (a very rapid reaction). A similar drop was noted for the hydrolysis of methyl ethanoate<\/a>. But there is a more significant difference. With guanidine, “hidden intermediates” are revealed. The transition state of course is marked by IRC=0.0, but soon after at IRC -2.0 the gradient drops, almost but not quite to zero. This is the characteristic signature a “hidden intermediate”, an effect induced by the guanidine. However, at IRC -3.0 the second proton transfers from the conjugate acid of guanidine (a “hidden” guanidinium cation) to the erstwhile oxygen of the carbonyl group (a “hidden” oxyanion), resulting in the creation of the tetrahedral intermediate in this reaction.<\/p>\n

\"oxime-guan-OG\"<\/p>\n

The IRC profile for the preferred N-nucleophilic addition (blue arrows<\/span>) is shown below. Again, the 2H2<\/sub>O reaction shows no trace of a hidden intermediate but the guanidine route clearly does. The (apparent) barrier decreases from ~8 kcal\/mol with water to ~2 kcal\/mol<\/a> with guanidine, and overall is 2.7 kcal\/mol lower than for O-nucleophilic attack.<\/p>\n\n\n\n\n
\"oxime-2H2O-N\"[3]<\/a><\/span><\/td>\n\"oxime-guan-N\"[4]<\/a><\/span><\/td>\n<\/tr>\n
\"oxime-guan-NG\"<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

There is a final feature. Propanone and hydroxylamine in the presence of guanidine form a “pre-complex” (an un-hidden intermediate<\/em>), with an intriguing distance of 1.619\u00c5 between the carbon of the carbonyl and the nitrogen of the hydroxylamine. This initial tetrahedral species is locked in by a network of unusually short hydrogen bonds and has a barrier to its formation<\/a> from the uncomplexed two reactants\u00a0of ~3 kcal\/mol (and a barrier onwards to the formation of a second tetrahedral intermediate of ~2 kcal\/mol as we saw before).<\/p>\n

\"N-pre\"<\/p>\n

\"preN\"<\/p>\n

So here ist a more complete picture of how an oxime forms from propanone and hydroxylamine under the influence of a more potent catalyst than water.<\/p>\n

    \n
  1. The barriers are significantly reduced by the use of guanidine.<\/li>\n
  2. An initial visible intermediate precedes any proton transfers<\/li>\n
  3. This is then followed by a “hidden one” following the first proton transfer<\/li>\n
  4. before settling into a final tetrahedral intermediate resulting from a second proton transfer, with the two proton transfers being part of a concerted asynchronous mechanism.<\/li>\n<\/ol>\n

    References<\/h2>\n
    1. H.S. Rzepa, \"Gaussian Job Archive for C3H13NO4\", 2013. https:\/\/doi.org\/10.6084\/m9.figshare.681655<\/a>\n\n<\/li>\n
    2. H.S. Rzepa, \"Gaussian Job Archive for C4H14N4O2\", 2013. https:\/\/doi.org\/10.6084\/m9.figshare.681656<\/a>\n\n<\/li>\n
    3. H.S. Rzepa, \"Gaussian Job Archive for C3H13NO4\", 2012. https:\/\/doi.org\/10.6084\/m9.figshare.95995<\/a>\n\n<\/li>\n
    4. H.S. Rzepa, \"Gaussian Job Archive for C4H14N4O2\", 2013. https:\/\/doi.org\/10.6084\/m9.figshare.681682<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> ","protected":false},"excerpt":{"rendered":"

      A recent theme here has been to subject to scrutiny well-known mechanisms supposedly involving intermediates. These transients can often involve the creation\/annihilation of charge separation resulting from \u00a0proton transfers, something that a cyclic mechanism can avoid. Here I revisit the formation of an oxime from hydroxylamine and propanone, but with one change. In the earlier […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_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}},"categories":[4],"tags":[843],"ppma_author":[2661],"class_list":["post-10184","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry","tag-reaction-mechanism"],"yoast_head":"\nIntermediates in oxime formation from hydroxylamine and propanone: now you see them, now you don't. - Henry Rzepa'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=10184\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Intermediates in oxime formation from hydroxylamine and propanone: now you see them, now you don't. - Henry Rzepa's Blog\" \/>\n<meta property=\"og:description\" content=\"A recent theme here has been to subject to scrutiny well-known mechanisms supposedly involving intermediates. These transients can often involve the creation\/annihilation of charge separation resulting from \u00a0proton transfers, something that a cyclic mechanism can avoid. Here I revisit the formation of an oxime from hydroxylamine and propanone, but with one change. In the earlier […]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa's Blog\" \/>\n<meta property=\"article:published_time\" content=\"2013-04-14T18:26:04+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2014-11-06T11:25:13+00:00\" \/>\n<meta property=\"og:image\" content=\"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/04\/NH2OH+Guanidine.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=\"3 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Intermediates in oxime formation from hydroxylamine and propanone: now you see them, now you don't. - Henry Rzepa'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=10184","og_locale":"en_GB","og_type":"article","og_title":"Intermediates in oxime formation from hydroxylamine and propanone: now you see them, now you don't. - Henry Rzepa's Blog","og_description":"A recent theme here has been to subject to scrutiny well-known mechanisms supposedly involving intermediates. These transients can often involve the creation\/annihilation of charge separation resulting from \u00a0proton transfers, something that a cyclic mechanism can avoid. Here I revisit the formation of an oxime from hydroxylamine and propanone, but with one change. In the earlier […]","og_url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184","og_site_name":"Henry Rzepa's Blog","article_published_time":"2013-04-14T18:26:04+00:00","article_modified_time":"2014-11-06T11:25:13+00:00","og_image":[{"url":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/04\/NH2OH+Guanidine.svg","type":"","width":"","height":""}],"author":"Henry Rzepa","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Henry Rzepa","Estimated reading time":"3 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184#article","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184"},"author":{"name":"Henry Rzepa","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#\/schema\/person\/2b40f7b9c872a4dc1547e040a11b6281"},"headline":"Intermediates in oxime formation from hydroxylamine and propanone: now you see them, now you don’t.","datePublished":"2013-04-14T18:26:04+00:00","dateModified":"2014-11-06T11:25:13+00:00","mainEntityOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184"},"wordCount":581,"commentCount":0,"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/04\/NH2OH+Guanidine.svg","keywords":["Reaction Mechanism"],"articleSection":["Interesting chemistry"],"inLanguage":"en-GB","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184#respond"]}]},{"@type":"WebPage","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184","name":"Intermediates in oxime formation from hydroxylamine and propanone: now you see them, now you don't. - Henry Rzepa's Blog","isPartOf":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website"},"primaryImageOfPage":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184#primaryimage"},"image":{"@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184#primaryimage"},"thumbnailUrl":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/04\/NH2OH+Guanidine.svg","datePublished":"2013-04-14T18:26:04+00:00","dateModified":"2014-11-06T11:25:13+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=10184#breadcrumb"},"inLanguage":"en-GB","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184"]}]},{"@type":"ImageObject","inLanguage":"en-GB","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184#primaryimage","url":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/04\/NH2OH+Guanidine.svg","contentUrl":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/04\/NH2OH+Guanidine.svg"},{"@type":"BreadcrumbList","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog"},{"@type":"ListItem","position":2,"name":"Intermediates in oxime formation from hydroxylamine and propanone: now you see them, now you don’t."}]},{"@type":"WebSite","@id":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/#website","url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/","name":"Henry Rzepa'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\/pDef7-2Eg","jetpack-related-posts":[{"id":7822,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7822","url_meta":{"origin":10184,"position":0},"title":"Oxime formation from hydroxylamine and ketone. Part 2: Elimination.","author":"Henry Rzepa","date":"September 25, 2012","format":false,"excerpt":"This is the follow-up to the previous post exploring a typical nucleophilic addition-elimination reaction. Here is the elimination step, which as before requires proton transfers. We again adopt a cyclic mechanism to try to avoid the build up of charge separation during those proton movements. Overall, the transition state for\u2026","rel":"","context":"In \"Reaction Mechanism\"","block_context":{"text":"Reaction Mechanism","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?tag=reaction-mechanism"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2012\/09\/N-2H2O-8-ring-2.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":8246,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=8246","url_meta":{"origin":10184,"position":1},"title":"Thalidomide. The role of water in the mechanism of its aqueous racemisation.","author":"Henry Rzepa","date":"November 10, 2012","format":false,"excerpt":"Thalidomide is a chiral molecule, which was sold in the 1960s as a sedative in its (S,R)-racemic form. The tragedy was that the (S)-isomer was tetragenic, and only the (R) enantiomer acts as a sedative. What was not appreciated at the time is that interconversion of the (S)- and (R)\u2026","rel":"","context":"In "Interesting chemistry"","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\/2012\/11\/thal1.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":7779,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7779","url_meta":{"origin":10184,"position":2},"title":"Oxime formation from hydroxylamine and ketone: a (computational) reality check on stage one of the mechanism.","author":"Henry Rzepa","date":"September 23, 2012","format":false,"excerpt":"The mechanism of forming an oxime from nucleophilic addition of a hydroxylamine to a ketone is taught early on in most courses of organic chemistry. Here I subject the first step of this reaction to form a tetrahedral intermediate to quantum mechanical scrutiny. The first decision is to decide which\u2026","rel":"","context":"In "Interesting chemistry"","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\/2012\/09\/hydroxylamine%2Bacetone-O-1H2O-6-ring_small.gif?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":23410,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=23410","url_meta":{"origin":10184,"position":3},"title":"The small-molecule antiviral compound Molnupiravir: an exploration of its tautomers.","author":"Henry Rzepa","date":"March 14, 2021","format":false,"excerpt":"For obvious reasons, anti-viral molecules are very much in the news at the moment. Thus Derek Lowe highlights Molnupiravir which is shown as a hydroxylamine, the representation originating from the Wikipedia page on the molecule. I like stereocentres more clearly identified using eg R\/S notation and so I went to\u2026","rel":"","context":"In "Interesting chemistry"","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.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/molnupiravir-1024x639.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":13047,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=13047","url_meta":{"origin":10184,"position":4},"title":"A computed mechanistic pathway for the formation of an amide from an acid and an amine in non-polar solution.","author":"Henry Rzepa","date":"November 12, 2014","format":false,"excerpt":"In London, one has the pleasures of attending occasional one day meetings at the Burlington House, home of the Royal Society of Chemistry. On November 5th this year, there was an excellent\u00a0meeting on the topic of Challenges in Catalysis,\u00a0and you can see the speakers and (some of) their slides here.\u2026","rel":"","context":"In "reaction mechanism"","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":5228,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=5228","url_meta":{"origin":10184,"position":5},"title":"The SN1 Mechanism for a third time. Exploration of the intrinsic reaction coordinate.","author":"Henry Rzepa","date":"October 25, 2011","format":false,"excerpt":"As the title hints, I have been here before. The SN1 solvolysis mechanism of t-butyl chloride was central to the flourishing of physical organic chemistry from the 1920s onwards, and it appears early on in most introductory lecture courses and text books. There we teach that it is a two-stage\u2026","rel":"","context":"In \"Historical\"","block_context":{"text":"Historical","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?tag=historical"},"img":{"alt_text":"","src":"http:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2011\/10\/sn11.svg","width":350,"height":200},"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","0":null,"1":"","2":"","3":"","4":"","5":"","6":"","7":"","8":""}],"_links":{"self":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/10184","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=10184"}],"version-history":[{"count":28,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/10184\/revisions"}],"predecessor-version":[{"id":13032,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/10184\/revisions\/13032"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10184"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10184"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10184"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=10184"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}