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Treatment of cycloalkanone dimethyl acetals 3 – 6 with sorbyl alcohol (=(2E,4E)‐hexa‐2,4‐dien‐1‐ol; 1 ) in the presence of acids afforded the novel cycloalkenones 8, 9, 11 , and 13 via a domino reaction (Claisen rearrangement with intramolecular ene reaction and retro‐ene reaction). Cyclopentenone 8 was readily transformed into 14 and 15 , methyl homologues of racemic methyl jasmonate ( 16 ) and methyl dihydrojasmonate (=Hedione®; 17 ), respectively. The organoleptic properties of 14 and 15 are also discussed. 相似文献
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The methyl acetal of methyl phenylglyoxylate has been prepared from halophenylethynes, N-iodosuccinimide and catalytic amounts of (hydroxy(p-tosyloxy)iodo)benzene or p-toluenesulfcnic acid in methanol at room temperature. 相似文献
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Onys'ko P. P. Rassukanaya Yu. V. Sinitsa A. D. 《Russian Journal of General Chemistry》2002,72(11):1699-1702
The first example of trifluoropyruvate phosphorylimines was prepared, and its capability for O- and S-amidoalkylation of water, alcohols, and compounds with the SH function was shown. Phenol and 4-methoxyphenol are O-alkylated, while 3-dimethylaminophenol and indole undergo regiospecific C-alkylation at the site of the highest -electron density. 相似文献
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Methyl hydrodisulfide and methyl deuterodisulfide have been prepared in a four-step synthesis. These compounds have been characterized spectroscopically including microwave spectra. 相似文献
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Abstract Methyl (methyl α-D-(9a), α-(9b), β-D-(10a), and β-L-(10b) idopyranosid)uronates were synthesized from myo-inositol. Baeyer-Villiger oxidation of the optically resolved inosose derivatives (3a and 3b) proceeded regioselectively to afford 4a and 4b in high yields, respectively. Ring-opening of the 7-membered hemiacetal-lactones (4a and 4b) with acid and subsequent deprotection gave the title compounds. 相似文献
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胆酸甲酯(甲基)丙烯酰基衍生物的合成 总被引:1,自引:1,他引:0
以(甲基)丙烯酰氯为酰化剂,三乙胺做缚酸剂合成了分子中含有1~3个(甲基)丙烯酰基的胆酸衍生物。结果显示,以酰氯作酰化试剂,胆酸甲酯分子中3个羟基的反应活性顺序是:C3-OH>C12-OH>C7-OH。 相似文献
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Abstract 2,4,5-Tribromostyrene (TBSt) was copolymerized with methyl acrylate (MA) or methyl methacrylate (MMA) in a toluene solution using 2,2′-azobisisobutyronitrile as free radical initiator. The copolymerization reactivity ratios were found to be for the system TBSt / MA r1= 7.4 ± 1.2 (TBSt) and r2= 0.1 ± 1.4 (MA) and for the system TBSt / MMA r1 = 1.8 ± 0.2 (TBSt) and r2 = 0.1 ± 0.2 (MMA). The e and Q values were also calculated. The initial rate of copolymerization, as well as molecular weight of the obtained copolymers for both system linearly increase as the content of TBSt in the monomer mixture increases. Similar behavior has also been established for the course of the copolymerization reactions to high conversions. The resulting copolymers rapidly decompose at temperatures 20–800°C above the decomposition of corresponding (metha)crylate hompolymers. However, the glass transition temperature increases markedly with increasing TBS content. 相似文献
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A reproducible, large scale and practical synthesis of N-(benzyloxycarbonyl)-L-vinylglycine methyl ester starting from L-methionine methyl ester hydrochloride is described. 相似文献
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Jaana M. H. Pakarinen Pirjo Vainiotalo Chris L. Stumpf Diane T. Leeck Phillip K. Chou Hilkka I. Kenttämaa 《Journal of the American Society for Mass Spectrometry》1996,7(5):482-489
Examination of the reactions of the long-lived (>0.5-s) radical cations of CD3CH2COOCH3 and CH3CH2COOCD3 indicates that the long-lived, nondecomposing methyl propionate radical cation CH3CH2C(O)OCH 3 +· isomerizes to its enol form CH3CH=C(OH)OCH 3 +· (ΔH isomerization ? ?32 kcal/mol) via two different pathways in the gas phase in a Fourier-transform ion cyclotron resonance mass spectrometer. A 1,4-shift of a β-hydrogen of the acid moiety to the carbonyl oxygen yields the distonic ion ·CH2CH2C+ (OH)OCH3 that then rearranges to CH3CH=C(OH)OCH 3 +· probably by consecutive 1,5- and 1,4-hydrogen shifts. This process is in competition with a 1,4-hydrogen transfer from the alcohol moiety to form another distonic ion, CH3CH2C+(OH)OCH 2 · , that can undergo a 1,4-hydrogen shift to form CH3CH=C(OH)OCH 3 +· . Ab initio molecular orbital calculations carried out at the UMP2/6-31G** + ZPVE level of theory show that the two distonic ions lie more than 16 kcal/mol lower in energy than CH3CH2C(O)OCH 3 +· . Hence, the first step of both rearrangement processes has a great driving force. The 1,4-hydrogen shift that involves the acid moiety is 3 kcal/mol more exothermic (ΔH isomerization=?16 kcal/mol) and is associated with a 4-kcal/mol lower barrier (10 kcal/mol) than the shift that involves the alcohol moiety. Indeed, experimental findings suggest that the hydrogen shift from the acid moiety is likely to be the favored channel. 相似文献