| 词条 | Triacetic acid lactone |
| 释义 |
| ImageFile = Triacetic acid lactone.svg | ImageSize = 150px | IUPACName = 4-Hydroxy-6-methyl-2H-pyran-2-one | OtherNames ={{flatlist|
|Section1={{Chembox Identifiers | CASNo = 675-10-5 | CASNo_Ref = {{cascite|correct|}} | PubChem = | ChemSpiderID = 10229807 | SMILES = C/C1=CC(\\O)=C/C(=O)O1 | InChI = 1/C6H6O3/c1-4-2-5(7)3-6(8)9-4/h2-3,7H,1H3 | InChIKey = NSYSSMYQPLSPOD-UHFFFAOYAI | StdInChI = 1S/C6H6O3/c1-4-2-5(7)3-6(8)9-4/h2-3,7H,1H3 | StdInChIKey = NSYSSMYQPLSPOD-UHFFFAOYSA-N | EC_number = 211-619-2 |Section2={{Chembox Properties | C=6 | H=6 | O=3 | MolarMass = 126.12 g mol−1 | Appearance = light yellow crystal powder | Density = 1.348 g cm−3 | MeltingPtC = 188 to 190 | BoilingPtC = 285.9 | Solubility =8.60 g L-1 at 20°C in H2O |Section3={{Chembox Hazards | MainHazards = Moderately Toxic | FlashPtC = 127.9 | AutoignitionPtC = }} Triacetic acid lactone (TAL;[1] 4-hydroxy-6-methyl-2-pyrone) is an organic compound derived enzymatically from glucose. It is a light yellow solid that is soluble in organic solvents. StructureTriacetic acid lactone consists of two main tautomers. {{clear-left}}The tautomer on the left, featuring a 4-hydroxy group, the C4 carbon, is dominant. Triacetic acid lactone is classified as a 2-pyrone compound owing to the ketone group on the C2 carbon in its dominant form. SynthesisTriacetic acid lactone is synthesized either from dehydroacetic acid, another 2-pyrone derivative, or from glucose by enzymatic catalysis. In its original synthesis, triacetic acid lactone was obtained by treatment of dehydroacetic acid with sulfuric acid at 135 °C. Dehydroacetic acid undergoes ring-opening and hydration to form "tetracetic acid".[2] Upon cooling, triacetic acid reverts to a lactone ring similar to the dehydroacetic acid structure, and the triacetic acid lactone is recovered by crystallization in cold water. {{clear-left}}BiosynthesisThe microbial synthesis of triacetic acid lactone requires the enzyme 2-pyrone synthase (2-PS).[3] This enzyme has been examined in two hosts Escherichia coli and Saccharomyces cerevisiae. The Saccharomyces cerevisiae host being used during the synthesis produces a higher yield (70%) compared with the Escherichia coli host, which produces a yield of 40% of triacetic acid lactone. This enzyme catalyzes the synthesis of triacetic acid lactone from acetyl-CoA via two subsequent condensations with malonyl-CoA. This produces an intermediate of 3,5-diketohexanoate thioester, which undergoes ring closure to produce triacetic acid lactone. ReactivityThe lactone is a versatile intermediate in organic synthesis.[4] It has also been described as a platform chemical, meaning that it could be the precursor to other fine chemicals. The lactone undergoes decarboxylation to acetylacetone. It is also a precursor to sorbic acid, dienoic acid, and hexenoic acid. Dienoic acid is used to inhibit the growth of various molds and hexenoic acid is used as a flavoring agent.[5] Acetylacetone is used for metal extraction and plating and as a food additive.[6] References1. ^{{Cite press release|title=New Sustainable Production Method Could Advance Plastics and Pharmaceuticals|date=13 February 2018|publisher=University of Texas|url=https://www.dddmag.com/news/2018/02/new-sustainable-production-method-could-advance-plastics-and-pharmaceuticals|via=Drug Discovery & Development Magazine}} 2. ^{{cite journal | doi = 10.1039/CT8915900607 | title = LVI.?The lactone of triacetic acid | year = 1891 | last1 = Collie | first1 = J. Norman | journal = Journal of the Chemical Society, Transactions | volume = 59 | pages = 607}} 3. ^{{cite journal | doi = 10.1002/bit.20759 | title = Microbial synthesis of triacetic acid lactone | year = 2006 | last1 = Xie | first1 = Dongming | last2 = Shao | first2 = Zengyi | last3 = Achkar | first3 = Jihane | last4 = Zha | first4 = Wenjuan | last5 = Frost | first5 = John W. | last6 = Zhao | first6 = Huimin | journal = Biotechnology and Bioengineering | volume = 93 | issue = 4 | pages = 727–36 | pmid = 16245348}} 4. ^{{cite journal | doi = 10.1016/S0065-2725(08)60861-2 | title = Dehydroacetic Acid, Triacetic Acid Lactone, and Related Pyrones | journal= Advances in Heterocyclic Chemistry | year = 1992 | last1 = Moreno-Mañas | first1 = Marcial | last2 = Pleixats | first2 = Roser | isbn = 9780120207534 | volume = 53 | pages = 1}} 5. ^{{cite journal | author = Jacoby, Mitch | title = Teaming Up for Biobased Chemicals | journal = Chem. Eng. News | year = 2012 | volume = 90 | issue = 32 | pages = 37–38}} 6. ^{{cite journal | doi = 10.1039/C2GC35343A | title = Triacetic acid lactone as a potential biorenewable platform chemical | year = 2012 | last1 = Chia | first1 = Mei | last2 = Schwartz | first2 = Thomas J. | last3 = Shanks | first3 = Brent H. | last4 = Dumesic | first4 = James A. | journal = Green Chemistry | volume = 14 | issue = 7 | pages = 1850}} 2 : 2-Pyrones|Phenols |
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