{{about|1,3-dioxolane|the other dioxolane isomer|1,2-dioxolane}} {{chembox |Verifiedfields = changed |Watchedfields = changed |verifiedrevid = 444710218 |Reference=<ref>[http://www.sigmaaldrich.com/catalog/ProductDetail.do?N4=184497|SIAL&N5=SEARCH_CONCAT_PNO|BRAND_KEY&F=SPEC 1,3-Dioxolane] at Sigma-Aldrich</ref> |Name = Dioxolane |ImageFileL1 = 1,3-dioxolane-2D-skeletal.png |ImageFileR1 = 1,3-dioxolane-3D-balls.png |PIN = 1,3-Dioxolane<ref>{{cite book | title = Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book) | publisher = The Royal Society of Chemistry | date = 2014 | location = Cambridge | page = 145 | doi = 10.1039/9781849733069-FP001 | isbn = 978-0-85404-182-4| chapter = Front Matter }}</ref> |SystematicName = 1,3-Dioxacyclopentane |OtherNames = Dioxolane <br /> 5-Crown-2 <br /> Formal glycol<ref>[https://pubchem.ncbi.nlm.nih.gov/compound/12586 formal glycol - PubChem Public Chemical Database]</ref> |Section1 = {{Chembox Identifiers |ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |ChemSpiderID = 12066 |PubChem = 12586 |ChEBI_Ref = {{ebicite|correct|EBI}} |ChEBI = 87597 | ChEMBL = 3187281 |EINECS = 211-463-5 |InChI = 1/C3H6O2/c1-2-4-5-3-1/h1-3H2 |InChIKey = SNQXJPARXFUULZ-UHFFFAOYAS |StdInChI_Ref = {{stdinchicite|correct|chemspider}} |StdInChI = 1S/C3H6O2/c1-2-4-5-3-1/h1-3H2 |StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |StdInChIKey = SNQXJPARXFUULZ-UHFFFAOYSA-N |CASNo_Ref = {{cascite|correct|CAS}} |CASNo = 646-06-0 |UNII_Ref = {{fdacite|correct|FDA}} |UNII = Y57RBG19JL | UNNumber = 1166 |SMILES = O1CCOC1 }} |Section2 = {{Chembox Properties |Formula = C<sub>3</sub>H<sub>6</sub>O<sub>2</sub> |MolarMass = 74.08 g/mol |Density = 1.06 g/cm<sup>3</sup> |MeltingPtC = -95 |BoilingPtC = 75}} |Section7 = {{Chembox Hazards | GHS_ref=<ref>{{cite web |title=1,3-Dioxolane |url=https://pubchem.ncbi.nlm.nih.gov/compound/12586#section=Safety-and-Hazards |website=pubchem.ncbi.nlm.nih.gov |language=en}}</ref> | GHSPictograms = {{GHS02}} | GHSSignalWord = Danger | HPhrases = {{H-phrases|225}} | PPhrases = {{P-phrases|210|233|240|241|242|243|280|303+361+353|370+378|403+235|501}} }} }}

'''Dioxolane''' is a heterocyclic acetal with the chemical formula (CH<sub>2</sub>)<sub>2</sub>O<sub>2</sub>CH<sub>2</sub>. It is related to tetrahydrofuran (THF) by replacement of the methylene group (CH<sub>2</sub>) at the 3-position with an oxygen atom. The corresponding saturated 6-membered C<sub>4</sub>O<sub>2</sub> rings are called dioxanes. The isomeric 1,2-dioxolane (wherein the two oxygen centers are adjacent) is a peroxide. 1,3-dioxolane is used as a solvent and as a comonomer in polyacetals.

==As a class of compounds== '''Dioxolanes''' are a group of organic compounds containing the dioxolane ring. Dioxolanes can be prepared by acetalization of aldehydes and ketalization of ketones with ethylene glycol.<ref>{{OrgSynth |author=R. A. Daignault, E. L. Eliel |year=1973 |title=2-Cyclohexyloxyethanol (involves acetalisation of cyclohexanone) |volume= |pages= |collvol=5 |collvolpages=303 |prep=CV5P0303}}</ref>

:center|synthesis of dioxolane group

(+)-''cis''-Dioxolane is the trivial name for {{chem name|<small>L</small>-(+)-''cis''-2-methyl-4-trimethylammoniummethyl-1,3-dioxolane iodide}} which is a muscarinic acetylcholine receptor agonist.

==Protecting groups== Organic compounds containing carbonyl groups sometimes need protection so that they do not undergo reactions during transformations of other functional groups that may be present. A variety of approaches to protection and deprotection of carbonyls<ref name = Greene /> including as dioxolanes<ref name = Greene2>{{cite book|chapter = 1,3-Dioxanes, 1,3-Dioxolanes|first1 = Theodora W.|last1 = Greene|first2 = Peter G. M.|last2 = Wuts|title = Greene's Protective Groups in Organic Synthesis|edition = 3rd|publisher = Wiley-Interscience|year = 1999|pages = 308–322, 724–727|url = https://www.organic-chemistry.org/protectivegroups/carbonyl/dioxanes-dioxolanes.htm|access-date = June 20, 2017|isbn = 9780471160199|archive-date = December 7, 2016|url-status = live|archive-url = https://web.archive.org/web/20161207144346/http://www.organic-chemistry.org/protectivegroups/carbonyl/dioxanes-dioxolanes.htm}}</ref> are known. For example, consider the compound methyl cyclohexanone-4-carboxylate, where lithium aluminium hydride reduction will produce 4-hydroxymethylcyclohexanol. The ester functional group can be reduced without affecting the ketone by protecting the ketone as a ketal. The ketal is produced by acid catalysed reaction with ethylene glycol, the reduction reaction carried out, and the protecting group removed by hydrolysis to produce 4-hydroxymethylcyclohexanone.

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NaBArF<sub>4</sub> can also be used for deprotection of acetal or ketal-protected carbonyl compounds.<ref name = Greene>{{cite book|chapter = Dimethyl acetals|first1 = Theodora W.|last1 = Greene|first2 = Peter G. M.|last2 = Wuts|title = Greene's Protective Groups in Organic Synthesis|edition = 3rd|publisher = Wiley-Interscience|year = 1999|pages = 297–304, 724–727|url = https://www.organic-chemistry.org/protectivegroups/carbonyl/dimethylacetals.htm|access-date = June 20, 2017|isbn = 9780471160199|archive-date = December 3, 2016|url-status = live|archive-url = https://web.archive.org/web/20161203200424/http://www.organic-chemistry.org/protectivegroups/carbonyl/dimethylacetals.htm}}</ref><ref name = Greene2 /> For example, deprotection of 2-phenyl-1,3-dioxolane to benzaldehyde can be achieved in water in five minutes at 30&nbsp;°C.<ref>{{cite journal|title = Deprotection of Acetals and Ketals in a Colloidal Suspension Generated by Sodium Tetrakis(3,5-trifluoromethylphenyl)borate in Water|first1 = Chih-Ching|last1 = Chang|first2 = Bei-Sih|last2 = Liao|first3 = Shiuh-Tzung|last3 = Liu|journal = Synlett|year = 2007|volume = 2007|issue = 2|pages = 283–287|doi = 10.1055/s-2007-968009}}</ref>

::PhCH(OCH<sub>2</sub>)<sub>2</sub> &nbsp; + &nbsp; H<sub>2</sub>O &nbsp; <chem>->[\ce{NaBAr4}][\text{30 °C / 5 min}]</chem>&nbsp;PhCHO&nbsp;+&nbsp;HOCH<sub>2</sub>CH<sub>2</sub>OH

==Natural products== Neosporol is a natural product that includes a 1,3-dioxolane moiety, and is an isomer of sporol which has a 1,3-dioxane ring.<ref name = NatProd>{{cite book|chapter-url = https://books.google.com/books?id=OjO78KV6USAC&pg=PA222|chapter = 10. Neosporol, Sporol|pages = 222–224|series = The Total Synthesis of Natural Products|volume = 11|title = Part B: Bicyclic and Tricyclic Sesquiterpenes|editor1-first = Michael C.|editor1-last = Pirrung|editor2-first = Andrew T.|editor2-last = Morehead|editor3-first = Bruce G.|editor3-last = Young|publisher = John Wiley & Sons|year = 2000|isbn = 9780470129630}}</ref> The total synthesis of both compounds has been reported, and each includes a step in which a dioxolane system is formed using trifluoroperacetic acid (TFPAA), prepared by the hydrogen peroxide &ndash; urea method.<ref name = UHP>{{cite journal|last1 = Ziegler|first1 = Fredrick E.|last2 = Metcalf|first2 = Chester A.|last3 = Nangia|first3 = Ashwini|last4 = Schulte|first4 = Gayle|title = Structure and total synthesis of sporol and neosporol|journal = J. Am. Chem. Soc.|year = 1993|volume = 115|issue = 7|pages = 2581–2589|doi = 10.1021/ja00060a006}}</ref><ref name = eEROS2012>{{cite encyclopedia|doi = 10.1002/047084289X.rt254.pub2|encyclopedia = e-EROS Encyclopedia of Reagents for Organic Synthesis|title = Trifluoroperacetic Acid|first1 = Kenneth C.|last1 = Caster|first2 = A. Somasekar|last2 = Rao|first3 = H. Rama|last3 = Mohan|first4 = Nicholas A.|last4 = McGrath|first5 = Matthew|last5 = Brichacek|year = 2012|isbn = 978-0471936237}}</ref> This method involves no water, so it gives a completely anhydrous peracid,<ref>{{cite journal|title = Oxidation Reactions Using Urea–Hydrogen Peroxide; A Safe Alternative to Anhydrous Hydrogen Peroxide|journal = Synlett|year = 1990|volume = 1990|issue = 9|pages = 533–535|doi = 10.1055/s-1990-21156|first1 = Mark S.|last1 = Cooper|first2 = Harry|last2 = Heaney|author-link2 = Harry Heaney|first3 = Amanda J.|last3 = Newbold|first4 = William R.|last4 = Sanderson}}</ref> necessary in this case as the presence of water would lead to unwanted side reactions.<ref name = UHP />

:{{chem|CF|3|COOCOCF|3}} &nbsp; + &nbsp; {{chem|H|2|O|2|•CO(NH|2|)|2}} &nbsp; → &nbsp; {{chem|CF|3|COOOH}} &nbsp; + &nbsp; {{chem|CF|3|COOH}} &nbsp; + &nbsp; {{chem|CO(NH|2|)|2}}

In the case of neosporol, a Prilezhaev reaction<ref>{{cite book|chapter = Prilezhaev reaction|pages = 274–281|last = Hagen|first = Timothy J.|chapter-url = https://books.google.com/books?id=WZ0DxnPNAdAC&pg=PA274|title = Name Reactions of Functional Group Transformations|editor1-first = Jie Jack|editor1-last = Li|editor2-first = E. J.|editor2-last = Corey|editor2-link = Elias James Corey|publisher = John Wiley & Sons|year = 2007|isbn = 9780470176504}}</ref> with trifluoroperacetic acid is used to convert a suitable allyl alcohol precursor to an epoxide, which then undergoes a ring-expansion reaction with a proximate carbonyl functional group to form the dioxolane ring.<ref name = UHP /><ref name = eEROS2012 />

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A similar approach is used in the total synthesis of sporol, with the dioxolane ring later expanded to a dioxane system.<ref name = NatProd />

==See also== * Dioxane

==References== {{reflist}}

==External links== * [https://web.archive.org/web/20121023040921/http://www.epa.gov/oppt/chemrtk/pubs/summaries/dioxlne/c12846.pdf environmental and toxicological data]

{{Muscarinic acetylcholine receptor modulators}}

Category:Dioxolanes Category:Muscarinic agonists Category:Solvents Category:Protecting groups Category:Formals