4417-81-6Relevant articles and documents
Quantitation of Important Roast-Smelling Odorants in Popcorn by Stable Isotope Dilution Assays and Model Studies on Flavor Formation during Popping
Schieberle, Peter
, p. 2442 - 2448 (1995)
Stable isotope dilution assays were developed for the quantitation of the roast-smelling popcorn odorants, 2-acetyl-tetrahydropyridine (ACTPY) and 2-propionyl-1-pyrroline (PPY).Both and, in addition, the two further roast-aroma compounds, 2-acetyl-1-pyrroline (ACPY) and acetylpyrazine, were quantified in different popcorn samples.In fresh hot-air popped corn, ACTPY showed the highest concentration (437 μg/kg), followed by ACPY (24 μg/kg) which were established as the key contributors to the roasty popcorn odor.During storage of a popcorn sample for seven days in a sealed polyethylene bag, the concentrations of ACTPY, ACPY, and PPY decreased to about one third.Model studies using aqueous maize extracts and distinct precursor compounds revealed the pair proline/fructose as the most effective precursor system in ACTPY formation, while the pair 1-pyrroline/2-oxopropanal was most effective in the generation of ACPY.A reaction scheme suggesting that ACPY is formed by an "acylation" of the intermediate 1-pyrroline by 2-oxopropanal in discussed.Keywords: 2-Acetyltetrahydropyridine; 2-acetyl-1-pyrroline; 2-propionyl-2-pyrroline; 2-benzoyl-1-pyrroline; stable isotope dilution assay; popcorn; flavor formation
Model Reactions on Roast Aroma Formation. 15. Investigations on the Formation of Pyridoimidazoles during the Maillard Reaction
Gi, Un-Sook,Baltes, Werner
, p. 2226 - 2230 (1995)
When aqueous solutions of histidine and glucose were heated to 100, 120, 150, or 180 deg C or when this mixture was roasted at 220 deg C, a total of 231 volatile compounds were identified.Among them 2-acetyl- and 2-propionylpyridoimidazole were found.Their formation pathway via a reaction of pyruvic aldehyde or 2-oxobutyraldehyde with, respectively, histidine or histimine is discussed.Experiments with 13C isotope labeled glucose point out that the terminal methyl groups of both aldehydes can arise from C-1 as well as C-6 of glucose.While pyruvic aldehyde can be formed by retro aldol scission of intermediate diacetylformoin, 2-oxobutyraldehyde was obviously formed from 2,5-dimethyl-4-hydroxy-3(2H)-furanone.By reaction of 1-, 2-, or 3-methylhistidine with glucose seven more pyridoimidazoles were identified, the structures of which, like the structures of the above-mentioned compounds, were unknown up to now.Keywords: Roast aromas; Maillard reaction; pyridoimidazoles; isotope labeling
Catalytic Synthesis of 1 H-2-Benzoxocins: Cobalt(III)-Carbene Radical Approach to 8-Membered Heterocyclic Enol Ethers
De Bruin, Bas,De Zwart, Felix J.,Li, Zirui,Mathew, Simon,Wolzak, Lukas A.,Zhou, Minghui
supporting information, p. 20501 - 20512 (2021/12/03)
The metallo-radical activation of ortho-allylcarbonyl-aryl N-arylsulfonylhydrazones with the paramagnetic cobalt(II) porphyrin catalyst [CoII(TPP)] (TPP = tetraphenylporphyrin) provides an efficient and powerful method for the synthesis of novel 8-membered heterocyclic enol ethers. The synthetic protocol is versatile and practical and enables the synthesis of a wide range of unique 1H-2-benzoxocins in high yields. The catalytic cyclization reactions proceed with excellent chemoselectivities, have a high functional group tolerance, and provide several opportunities for the synthesis of new bioactive compounds. The reactions are shown to proceed via cobalt(III)-carbene radical intermediates, which are involved in intramolecular hydrogen transfer (HAT) from the allylic position to the carbene radical, followed by a near-barrierless radical rebound step in the coordination sphere of cobalt. The proposed mechanism is supported by experimental observations, density functional theory (DFT) calculations, and spin trapping experiments.
Emimycin and its nucleoside derivatives: Synthesis and antiviral activity
Plebanek, Elzbieta,Lescrinier, Eveline,Andrei, Graciela,Snoeck, Robert,Herdewijn, Piet,De Jonghe, Steven
, p. 93 - 103 (2017/12/26)
The synthesis of emimycin, 5-substituted emimycin analogues and the corresponding ribo- and 2′-deoxyribonucleoside derivatives is described. Emimycin, its 5-substituted congeners and the ribonucleoside derivatives are completely devoid of antiviral activity against RNA viruses. In contrast, some of the 2′-deoxyribosyl emimycin derivatives are potent inhibitors of the replication of herpes simplex virus-1 and varicella-zoster virus, lacking cytotoxicity.
Diarylprolinol in an asymmetric aldol reaction of an α-alkyl-α- oxo aldehyde as an electrophile
Hayashi, Yujiro,Yasui, Yusuke,Kojima, Masahiro,Kawamura, Tsuyoshi,Ishikawa, Hayato
supporting information; experimental part, p. 4570 - 4572 (2012/06/01)
The direct aldol reaction of an α-alkyl-α-oxo aldehyde was catalyzed by trifluoromethyl-substituted diarylprolinol 1 to afford a γ-oxo-β-hydroxy-α-substituted aldehyde in good yield with excellent anti-selectivity and excellent enantioselectivity. The Royal Society of Chemistry 2012.
The gas-phase ozonolysis of 1-penten-3-ol, (Z)-2-penten-1-ol and 1-penten-3-one: Kinetics, products and secondary organic aerosol Formation
O'Dwyer,Carey,Healy,Wenger,Picquet-Varrault,Doussin
experimental part, p. 1059 - 1080 (2011/02/17)
The gas-phase ozonolysis of the biogenic unsaturated compounds 1-penten-3-ol, (Z)-2-penten- 1-ol and 1-penten-3-one has been investigated in two atmospheric simulation chambers. The following rate coefficients (in units of 10-17 cm3 molecule-1 s-1) were determined at atmospheric pressure and 293±2 K using an absolute rate method: 1-penten-3-ol, (1.64±0.15); (Z)-2- penten-1-ol, (11.5±0.66); 1-penten-3-one, (1.17±0.15). Reaction products were identified by in situ FTIR spectroscopy and gas chromatography - mass spectrometry (GC-MS). The major products and their average molar yields in the presence of a radical scavenger at relative humidity 1% were: formaldehyde (0.49±0.02), 2-hydroxybutanal (0.46±0.03) and propanal (0.15±0.02) from 1-penten-3-ol; propanal (0.39±0.03) and glycolaldehyde (0.43±0.04) from (Z)-2-penten-1-ol; formaldehyde (0.37±0.02) and 2-oxobutanal (0.49±0.03) from 1-penten-3- one. The formation of secondary organic aerosol was also observed with yields ranging from 0.13-0.17 for the unsaturated alcohols. Significantly lower yields of around 0.03 were measured for 1-penten-3-one. The results of this work are used to determine atmospheric lifetimes and reaction mechanisms for the gas-phase ozonolysis of 1-penten-3-ol, (Z)-2-penten-1-ol and 1- penten-3-one. The broader atmospheric implications of this work are also discussed. by Oldenbourg Wissenschaftsverlag.
Gas-phase reaction of ozone with trans-2-hexenal, trans-2-hexenyl acetate, ethylvinyl ketone, and 6-methyl-5-hepten-2-one
Grosjean, Eric,Grosjean, Daniel,Seinfeld, John H.
, p. 373 - 382 (2007/10/03)
The gas-phase reaction of ozone with the unsaturated oxygenates trans-2-hexenal, trans-2-hexenyl acetate, ethylvinyl ketone, and 6-methyl-5-hepten-2-one, which are components of biogenic emissions and/or close structural homologues thereof, has been investigated at atmospheric pressure and ambient temperature (286-291 K) and humidity (RH = 55 ± 10%). Reaction rate constants, in units of 10-18 cm3 molecule-1 s-1, are 1.28 ± 0.28 for trans2-hexenal, 21.8 ± 2.8 for trans-2-hexenyl acetate, and 394 ± 40 for 6-methyl-5-hepten-2-one. Carbonyl product formation yields, measured with sufficient cyclohexane added to scavenge the hydroxyl radical, are 0.53 ± 0.06 for n-butanal and 0.56 ± 0.04 for glyoxal from trans-2-hexenal, 0.47 ± 0.02 for n-butanal and 0.58 ± 0.14 for 1-oxoethyl acetate from trans-2-hexenyl acetate, 0.55 ± 0.07 for formaldehyde and 0.44 ± 0.03 for 2-oxobutanal from ethylvinyl ketone, and 0.28 ± 0.02 for acetone from 6-methyl-5-hepten-2-one. Reaction mechanisms are outlined and the atmospheric persistence of the compounds studied is briefly discussed.
Atmospheric Chemistry of 2-Ethyl Acrolein
Grosjean, Daniel,Grosjean, Eric,Williams, Edwin L.
, p. 365 - 373 (2007/10/02)
The atmospheric oxidation of the unsaturated aldehyde 2-ethyl acrolein, CH2=C(C2H5)CHO, has been studied in laboratory experiments involving the reaction of ozone with 2-ethyl acrolein in the dark (with cyclohexane added to scavenge the hydroxyl radical), and the sunlight irradiation of 2-ethyl acrolein with NO in air.The major carbonyl products of the 2-ethyl acrolein reaction with ozone are formaldehyde, acetaldehyde, and the dicarbonyl ethylglyoxal, CH3CH2COCHO.Sunlight irradiation of 2-ethyl acrolein and NO led to the formation of three carbonyls (formaldehyde, acetaldehyde, and ethylglyoxal) and three peroxyacyl nitrates, (RC(O)OONO2), including PAN (R = CH3), PPN (R = C2H5, and the unsaturated compound EPAN (R = CH2=C(C2H5).Mechanisms are outlined for the reactions of ozone and of the hydroxyl radical with 2-ethyl acrolein.These mechanisms are consistent with the observed carbonyl and peroxyacyl nitrate products.Thermal decomposition, a major atmospheric removal process for peroxyacyl nitrates, has been studied for EPAN.The decomposition rate of EPAN relative to that of PAN is 0.59-0.73 at 292-294 K and 1 atm of air.Atmospheric implication of these results are discussed.
Kinetics of Oxidation of Alcohols, Diols and α-Hydroxy Acids by Os(VIII) in Aqueous Alkaline Medium: Evidence in Support of Hydride Ion Abstraction Mechanism
Somaiah, P. Veera,Reddy, K. Bal,Sethuram, B.,Rao, T. Navaneeth
, p. 876 - 879 (2007/10/02)
Kinetics of oxidation of alcohols, diols and α-hydroxy acids by OsO4 in aqueous alkaline medium have been studied spectrocolorimetrically at 400 nm.The order in and is found to be unity each.Increase in increases the rate and the order in is 1.0.No evidence for complex formation has been observed in all these reactions.The products of oxidation are identified as the corresponding carbonyl compounds. A mechanism involving hydride ion abstraction by the oxidant in a slow step is proposed.
A LIPOSOLUBLE CATIONIC COMPLEX OF Ru(II) BASED ON 1,4,5,8-TETRA-AZAPHENANTHRENE
Nasielski, J.,Garcia, M. L.,Abeledo, M. L.,Nasielski-Hinkens, R.
, p. 743 - 750 (2007/10/02)
Reacting 2,2-dichlorododecanal with 1,2-diamino-4-nitrobenzene in dioxane in the presence of a base gives a 46 percent yield of 2-decyl-6-nitroquinoxaline, which after amination by hydroxylamine and reduction gave 5,6-diamino-2-decylquinoxaline.This diamine, again with 2,2-dichlorododecanal in dioxane and base, affords 2,6-didecyl- and 2,7-didecyl-1,4,5,8-tetra-azaphenanthrene (2,7ddTAP); the latter ligand gives the hexane-soluble Ru(2,7ddTAP)3(PF6)2.
