{"id":23410,"date":"2021-03-14T08:30:12","date_gmt":"2021-03-14T08:30:12","guid":{"rendered":"https:\/\/www.ch.imperial.ac.uk\/rzepa\/blog\/?p=23410"},"modified":"2021-03-14T08:57:43","modified_gmt":"2021-03-14T08:57:43","slug":"the-small-molecule-antiviral-compound-molnupiravir-an-exploration-of-its-tautomers","status":"publish","type":"post","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=23410","title":{"rendered":"The small-molecule antiviral compound Molnupiravir: an exploration of its tautomers."},"content":{"rendered":"<div class=\"kcite-section\" kcite-section-id=\"23410\">\n<p>For obvious reasons, anti-viral molecules are very much in the news at the moment. Thus Derek Lowe <a href=\"https:\/\/blogs.sciencemag.org\/pipeline\/archives\/2021\/03\/04\/molnupiravir-last-of-the-small-molecule-coronavirus-hopes\">highlights Molnupiravir <\/a>which is shown as a hydroxylamine, the representation originating from the <a href=\"https:\/\/en.wikipedia.org\/wiki\/Molnupiravir\" target=\"_blank\" rel=\"noopener\">Wikipedia page<\/a> on the molecule. <a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/MK-4482.svg\"><img decoding=\"async\" class=\"aligncenter size-large wp-image-23411\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/MK-4482.svg\" alt=\"\" width=\"250\" \/><\/a><\/p>\n<p>I like stereocentres more clearly identified using eg <em>R<\/em>\/<em>S<\/em> notation and so I went to another source of information, SciFinder, which represents the molecule in a different way. There you get the stereocentres unambiguously identified for you, but the hydroxylamine is now replaced by an oxime!\u00a0<\/p>\n<p><a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/2492423-29-5.png\"><img decoding=\"async\" class=\"aligncenter size-full wp-image-23412\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/2492423-29-5.png\" alt=\"\" width=\"400\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/2492423-29-5.png 728w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/2492423-29-5-300x119.png 300w\" sizes=\"(max-width: 728px) 100vw, 728px\" \/><\/a><\/p>\n<p>The Reaxys database renders it differently again as below (note the different rotamer for the hydroxylamine):\n<\/p>\n<p><a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-631.jpg\"><img decoding=\"async\" class=\"aligncenter size-full wp-image-23413\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-631.jpg\" alt=\"\" width=\"200\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-631.jpg 296w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-631-227x300.jpg 227w\" sizes=\"(max-width: 296px) 100vw, 296px\" \/><\/a><\/p>\n<p>Are they all talking about the same molecule? Well yes, since the hydroxylamine and the oxime are related by tautomerism, but it takes a bit of effort to fully reconcile these three representations with each other. So the next question is does it matter which tautomer is selected to represent a molecule? Since they differ by proton transfers between acidic atoms (N,O) the presumption is that the equilibrium between the tautomers is fast and so the predominant species is determined by the position of the equilibrium. The tautomer matters in another sense. This molecule clearly interacts with DNA, and very probably by paired hydrogen bonding. It is this hydrogen bonding that was crucial in helping Watson and Crick to postulate the first successful model of DNA itself,<span id=\"cite_ITEM-23410-0\" name=\"citation\"><a href=\"#ITEM-23410-0\">[1]<\/a><\/span> famously enabled by them using the correct tautomeric form of the component DNA bases! So the tautomers do matter!<\/p>\n<p>Time for some calculations (B3LYP+GD3BJ\/Def2-TZVPP\/SCRF=water, using integral=(acc2e=14,grid=superfinegrid). The FAIR DOI for the collection is <a href=\"https:\/\/doi.org\/10.14469\/hpc\/7990\">10.14469\/hpc\/7990<\/a><\/p>\n<p><a href=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Molnupiravir.svg\"><img decoding=\"async\" class=\"aligncenter size-large wp-image-23415\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Molnupiravir.svg\" alt=\"\" width=\"540\" \/><\/a><\/p>\n<p>In the diagram above, the non-aromatic valence representation is shown at the top, followed by a reorganisation of the electrons into an aromatic form below. These aromatic forms are all ionic with charge separation and so the question here arises: does the aromatic stabilisation energy outweigh the destabilisation caused by charge separation?\u00a0<\/p>\n<p>The calculated free energies (\u0394G<sub>298<\/sub>) show that the oxime is 3.2 kcal\/mol more stable than the next most stable, the hydroxylamine tautomer (calculated for a water continuum solvation model).The third tautomer is not far behind, being a nitrone! A 3D model is shown below illustrating the internal hydrogen bonds (I hope it is clear why\u00a0I wanted the four stereocentres unambiguously identified, and why the simple perspective diagram shown on the Wikipedia page is not definitive). This model was obtained after also experimenting with hydroxyl rotamers to ensure the lowest energy was obtained.<\/p>\n<div id=\"attachment_23416\" style=\"width: 460px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-23416\" class=\"size-large wp-image-23416\" onclick=\"jmolApplet([450,450],'load wp-content\/uploads\/2021\/03\/molnupiravir.log;frame 26;measure 34 42;measure 31 39;measure 38 37;spin 3;','c1');\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/molnupiravir-1024x639.jpg\" alt=\"\" width=\"450\" height=\"281\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/molnupiravir-1024x639.jpg 1024w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/molnupiravir-300x187.jpg 300w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/molnupiravir-768x479.jpg 768w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/molnupiravir-1536x958.jpg 1536w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/molnupiravir.jpg 2018w\" sizes=\"auto, (max-width: 450px) 100vw, 450px\" \/><p id=\"caption-attachment-23416\" class=\"wp-caption-text\">Click to load\u00a03D model<\/p><\/div>\n<p>So how &#8220;aromatic&#8221; are the two lowest energy species? The oxime has two sets of charge separation, whilst the hydroxylamine only one. One measure of aromaticity is the NICS magnetic index. For the oxime it is -0.1ppm, very clearly non-aromatic. Separating two sets of charges clearly is not compensated by aromatic stabilisation. The next most stable hydroxylamine has NICS -1.8ppm, which shows slightly more signs of aromaticity (benzene on this scale is ~ -10 ppm), perhaps because it only separates one pair of charges.\u00a0<\/p>\n<p>What about crystal structures? NETGEY is a model which removes the sugar unit and with an N-Me replacing the NH (thus preventing tautomerism and locking the molecule into the oxime form). MHCYTC protonates the hydroxylamine on the imine nitrogen OR the oxime on its imine nitrogen thus rendering the two tautomers identical.<\/p>\n<table border=\"0\">\n<tbody>\n<tr>\n<th>NETGEY<\/th>\n<th>MHCYTC<\/th>\n<\/tr>\n<tr>\n<td><img loading=\"lazy\" decoding=\"async\" onclick=\"jmolApplet([450,450],'load wp-content\/uploads\/2021\/03\/NETGEY.mol;','c2');\"  class=\"aligncenter size-medium wp-image-23421\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-632-242x300.jpg\" alt=\"\" width=\"242\" height=\"300\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-632-242x300.jpg 242w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-632.jpg 696w\" sizes=\"auto, (max-width: 242px) 100vw, 242px\" \/><\/td>\n<td><img loading=\"lazy\" decoding=\"async\" onclick=\"jmolApplet([450,450],'load wp-content\/uploads\/2021\/03\/MHCYTC.mol;','c3');\"  class=\"aligncenter size-medium wp-image-23420\" src=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-633-200x300.jpg\" alt=\"\" width=\"200\" height=\"300\" srcset=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-633-200x300.jpg 200w, https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-633.jpg 609w\" sizes=\"auto, (max-width: 200px) 100vw, 200px\" \/><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The crystal structure of Molnupiravir itself has not been reported, so there is no definitive answer to the most stable tautomer in the solid state. But the calculation above does suggest that it is the oxime (and hence SciFinder&#8217;s representation) that is the probable dominant form in aqueous solutions. If one is trying to build a model to show how this small molecule interacts with DNA, this might be useful information (in the same way that picking the correct tautomer of the original DNA bases worked for Watson and Crick!).\u00a0<\/p>\n<h2>References<\/h2>\n    <ol class=\"kcite-bibliography csl-bib-body\"><li id=\"ITEM-23410-0\">J.D. WATSON, and F.H.C. CRICK, \"Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid\", <i>Nature<\/i>, vol. 171, pp. 737-738, 1953. <a href=\"https:\/\/doi.org\/10.1038\/171737a0\">https:\/\/doi.org\/10.1038\/171737a0<\/a>\n\n<\/li>\n<\/ol>\n\n<\/div> <!-- kcite-section 23410 -->","protected":false},"excerpt":{"rendered":"<p>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 another source of information, SciFinder, [&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_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":[4],"tags":[],"ppma_author":[2661],"class_list":["post-23410","post","type-post","status-publish","format-standard","hentry","category-interesting-chemistry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>The small-molecule antiviral compound Molnupiravir: an exploration of its tautomers. - 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=23410\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The small-molecule antiviral compound Molnupiravir: an exploration of its tautomers. - Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"og:description\" content=\"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 another source of information, SciFinder, [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=23410\" \/>\n<meta property=\"og:site_name\" content=\"Henry Rzepa&#039;s Blog\" \/>\n<meta property=\"article:published_time\" content=\"2021-03-14T08:30:12+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2021-03-14T08:57:43+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/MK-4482.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":"The small-molecule antiviral compound Molnupiravir: an exploration of its tautomers. - 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=23410","og_locale":"en_GB","og_type":"article","og_title":"The small-molecule antiviral compound Molnupiravir: an exploration of its tautomers. - Henry Rzepa&#039;s Blog","og_description":"For obvious reasons, anti-viral molecules are very much in the news at the moment. 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now there is Paxlovid as a SARS-CoV-2 protease inhibitor. An NCI analysis of the ligand.","author":"Henry Rzepa","date":"November 13, 2021","format":false,"excerpt":"Earlier this year, Molnupiravir hit the headlines as a promising antiviral drug. This is now followed by Paxlovid, which is the first small molecule to be aimed by design at the SAR-CoV-2 protein and which is reported as reducing greatly the risk of hospitalization or death when given within three\u2026","rel":"","context":"In &quot;Chemical IT&quot;","block_context":{"text":"Chemical IT","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=2"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.ch.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/11\/paxlovid-1024x923.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":7779,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7779","url_meta":{"origin":23410,"position":1},"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 &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\/2012\/09\/hydroxylamine%2Bacetone-O-1H2O-6-ring_small.gif?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":23434,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=23434","url_meta":{"origin":23410,"position":2},"title":"Deltamethrin &#8211; a polymorphed insecticide.","author":"Henry Rzepa","date":"March 24, 2021","format":false,"excerpt":"Deltamethin is a pyrethroid insecticide for control of malaria which has been used for a little while. Perhaps inevitably, mosquitoes are developing resistance to it. So what could be done about countering this? Well, perhaps surprisingly, form a polymorph!\u00a0These crystal structure isomers are often highly undesirable; thus\u00a0Ritonavir, which changed its\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.ic.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2021\/03\/Screenshot-643-1024x716.jpg?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":16208,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=16208","url_meta":{"origin":23410,"position":3},"title":"Azane oxide, a tautomer of hydroxylamine.","author":"Henry Rzepa","date":"April 15, 2016","format":false,"excerpt":"In the previous post I described how hydronium hydroxide or H3O+...HO-, an intermolecular tautomer of water, has recently been observed captured inside an organic cage and how the free-standing species in water can be captured computationally with the help of solvating water bridges. Here I explore azane oxide or H3N+-O-,\u2021\u2026","rel":"","context":"In &quot;General&quot;","block_context":{"text":"General","link":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?cat=1"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":10184,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=10184","url_meta":{"origin":23410,"position":4},"title":"Intermediates in oxime formation from hydroxylamine and propanone: now you see them, now you don&#8217;t.","author":"Henry Rzepa","date":"April 14, 2013","format":false,"excerpt":"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\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":"N-pre","src":"https:\/\/i0.wp.com\/www.ch.imperial.ac.uk\/rzepa\/blog\/wp-content\/uploads\/2013\/04\/N-pre.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":7822,"url":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/?p=7822","url_meta":{"origin":23410,"position":5},"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":[]}],"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\/23410","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=23410"}],"version-history":[{"count":12,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/23410\/revisions"}],"predecessor-version":[{"id":23432,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=\/wp\/v2\/posts\/23410\/revisions\/23432"}],"wp:attachment":[{"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=23410"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=23410"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=23410"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.ch.ic.ac.uk\/rzepa\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fppma_author&post=23410"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}