2-Pyrones acid anhydrides

Hundreds of compounds have been identified in the volatile flavor components of processed foods. Hydrocarbons, alcohols, ethers, aldehydes, ketones, acids, acid anhydrides, esters, aromatic, lactones, pyrones, furans, pyridines, pyrroles, n-alkylpyrrole-2-aldehydes, pyrazines, sulfides, disulfides, thiols, thiophenes, thiazoles, trithiolanes, thialdine. ..etc. 

The isomeric 6-hydroxy-2-pyrone (glutaconic anhydride) and its 4-methyl analog (47) react similarly with aryldiazonium salts and on hydrolysis with dilute alkali or acid the hydrazones (48) are transformed into l-aryl-6-oxo-l,6-dihydro-3-pyridazinecarboxylic acids or their 4-methyl analogs (49) in variable yields (28-74%). 

Beilstein Handbook Reference) AI3-00753 Benzo-a-pyrone BRN 0383644 Caswell No. 259C CCRIS 181 Cinnamic acid, o-hydroxy-, 8-lKtone ois-o-Coumaric acid anhydride Coumarin cis-o-Coumarinic acid lactone Coumarinic anhydride Coumarinic lactone Cumarin EINECS 202-086-7 EPA Pesticide Chemical Code 127301 HSDB 1623 o-Hydroxycinnamic lactone 0-Hydroxyzimtsaure-lacton Kumarin NCI C07103 NSC 8774 Rattex Tonka bean camphor. Used in pharmaceuticals as a flavorant. Crystals mpo 71" bp = 301.7 d O = 0.936 Xm = 273, 311 nm (e = 11200, 6710, MeOH) moderately soluble in H2O, EtOH, more soluble in EtzO, CHCI3, C5H5N. Alfa Aesar Rhodia Inc. Rhodia Organique Fine Ltd. 

The catalytic reaction of complex 49 with dtbcH2 and dioxygen is less selective than that of 50. In addition to the formation of dtbq and 3,5-di-ter -butyl-l-oxa-cyclohepta-3,5-diene-2,7-dione, some muconic acid anhydride and 2-pyrone derivatives are also produced as a result of both intra- and extradiol insertion of one of the oxygen atoms from dioxygen. Such products are consistent with the mechanism in Scheme 10, with the proviso that both the rhodium and iridium systems share the same mechanism, at least in the initial stages of the reaction. 

Other Names Coumarin 1,2-Benzopyrone 2-Propenoic acid, 3-(2-hydroxyphenyl)-, 8-lactone 5,6-Benzo-2-pyrone Benzo-a-pyrone Coumarinic anhydride NSC 8774 Rattex Tonka bean camphor cis-o-Coumarinic acid lactone o-Hydroxycinnamic acid lactone CA Index Name 2H-l-Benzopyran-2-one CAS Registry Number 91-64-5 Merck Index Number 2562 Chemical Structure... 

Synonyms 1,2-Benzopyrone 5,6-benzo-2-pyrone benzo-a-pyrone cis-ortho-co x-marinic acid lactone coumarinic anhydride ort/jo-hydroxyciimamic acid lactone... 

Food, flavors consist of numerous compounds, none of which alone is characteristic of specific food. Classes of compounds which emcompass food flavors are - hydrocarbons (aliphatic, ali-cyclic, aromatic) carbonyls (aldehydes, ketones) carboxylic acids, esters, imides, anhydrides alcohols, phenols, ethers alkylamines, alkylimines aliphatic sulfur compounds (thiols, mono-, di- and tri-sulfides) nitrogen heterocyclics (pyrroles, pyrazines, pyridines) sulfur heterocylics (thiophenes, thiazoles, trithiolane, thialidine) and oxygen-heterocyclics (lactone, pyrone, furan). Discussion will be limited to striking developments in heterocyclics. 

SYNS 2H-1-BENZOPYRAN-2-ONE 1,2-BENZO-PYRONE cis-o-COUiMARINIC ACID LACTONE COUMARINIC ANHYDRIDE o-HYDROXYCINNAMIC ACID LACTONE o-HYDROXYZIMTSAEURE-LACTON (GERMAN) NCI-C60297 2-OXO-l,2-BENZOPYRAN RATTEX TONKA BE.YN CAMPHOR... 

Aromatic aldehydes react with 196, probably through the intermediate 197 in acetic acid or anhydride, without addition of base. This reaction, which leads to cations 198, has-been performed with various aldehydes benzaldehydes, cinnamaldehydes, salicylaldehydes, - " and 2-phenyl-4//-l-benzopyran-3-carbaldehyde. Similar reactions occur with ketones and pyrones but need a strong base as catalyst. 

The reactions of amidines or guanidines with a-functionalized carbonyl compounds continue to be utilized for the synthesis of imidazoles. Thus, the mixed anhydride of acetic and chloroacetic acids reacts with symmetrical diarylguanidines to give l-aryl-2-arylaminoimidazolin-4-ones, and there is competitive formation of imidazoles and pyrimidines in the reaction of benzamidine with 3-bromobenzo-4-pyrones (18). Imidazoles are minor products, but are favored in nonpolar solvents. The use of a-dicarbonyl compounds with guanidine gives 2-amino-4-hydroxy-4-methyl-4//-imid-azoles, which give excellent yields of 2-aminoimidazoles on catalytic hydrogenation. " ... 

Synonyms Coumarin 2f-f-l-Benzopyran-2-one 1,2-Benzopyrone cfs-o-Coumaric acid lactone Coumarinic anhydride 2-Oxo-l,2-benzopyran Tonka bean camphor note coumadin and warfarin are not synonyms for coumarin) Chemical/Pharmaceutical/Other Class Benzo-a-pyrone... 

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