3698-35-9Relevant academic research and scientific papers
Pd(ii)-catalyzed decarboxylative allylation and Heck-coupling of arene carboxylates with allylic halides and esters
Wang, Jiantao,Cui, Zili,Zhang, Yuexia,Li, Huajie,Wu, Long-Min,Liu, Zhongquan
supporting information; experimental part, p. 663 - 666 (2011/03/22)
This work demonstrates an alternative method to prepare allylated arenes and aryl-substituted allylic esters via catalytic decarboxylative C-C bond formation using aromatic carboxylic acids and allylic halides and esters.
Deprotonative metalation of substituted aromatics using mixed lithium-cobalt combinations
Dayaker, Gandrath,Chevallier, Floris,Gros, Philippe C.,Mongin, Florence
experimental part, p. 8904 - 8910 (2011/01/04)
The deprotonation of anisole was attempted using different homo- and heteroleptic TMP/Bu mixed lithium-cobalt combinations. Using iodine to intercept the metalated anisole, an optimization of the reaction conditions showed that in THF at room temperature 2 equiv of base were required to suppress the formation of the corresponding 2,2′-dimer. The origin of the dimer was not identified, but its formation was favored with allyl bromide as electrophile. The metalated anisole was efficiently trapped using iodine, anisaldehyde, and chlorodiphenylphosphine, and moderately employing benzophenone, and benzoyl chloride. 1,2-, 1,3-, and 1,4-dimethoxybenzene were similarly converted regioselectively to the corresponding iodides. It was observed that 2-methoxy- and 2,6-dimethoxypyridine were more prone to dimerization than the corresponding benzenes when treated similarly. Involving ethyl benzoate in the metalation-iodination sequence showed that the method was not suitable to functionalize substrates bearing reactive functions.
Dialkoxybenzene and dialkoxyallylbenzene feeding and oviposition deterrents against the cabbage looper, trichoplusia ni: Potential insect behavior control agents
Akhtar, Yasmin,Yu, Yang,Isman, Murray B.,Plettner, Erika
, p. 4983 - 4991 (2011/08/06)
The antifeedant, oviposition deterrent, and toxic effects of individual dialkoxybenzene compounds/sets and of hydroxy- or alkoxy-substituted allylbenzenes, obtained through Claisen rearrangement of substituted allyloxybenzenes, were assessed against the cabbage looper, Trichoplusia ni, in laboratory bioassays. Most of the compounds/sets strongly deterred larval feeding, with some exhibiting mild toxic and oviposition deterrent effects as well. Some of the compounds/sets were more active than the commercial insect repellent, DEET (N,N-diethyl-m-toluamide), as both feeding and oviposition deterrents against the cabbage looper. On the basis of the obtained oviposition data a general hypothesis was proposed regarding the oviposition sites: one binding mode with the alkyl and allyl groups on the same side of the benzene ring resulted in deterrence, the other with alkyl and allyl groups on opposite sides of the benzene ring resulted in stimulation. The results suggest some structure-activity relationships useful in improving the efficacy of the compounds and designing new, nontoxic insect control agents for agriculture.
STRUCTURE-ACTIVITY RELATIONSHIPS OF PHENYLPROPANOIDS AS GROWTH INHIBITORS OF THE GREEN ALGA SELENASTRUM CAPRICORNUTUM
Greca, Marina Della,Monaco, Pietro,Pollio, Antonino,Previtera, Lucio
, p. 4119 - 4124 (2007/10/02)
Twenty-seven commercial or synthetic phenylpropanoids have been tested in broth against the unicellular alga Selenastrum capricornutum.The antialgal activity seems to be linked to the number as well as to the position of the methoxyl group in the molecule.A slight effect of the side chain substitution was also observed. Key Word Index - Selenastrum capricornutum; allelochemicals; phenylpropanoids.
Palladium-Catalyzed Cross-Coupling Reactions of Highly Hindered, Electron-Rich Phenol Triflates and Organostannanes
Saa, Jose M.,Martorell, Gabriel,Garcia-Raso, Angel
, p. 678 - 685 (2007/10/02)
The palladium-catalyzed cross-coupling reaction of highly hindered, electron-rich phenol triflates and organostannanes (Stille reaction) has been studied in a systematic manner.The following are its salient features: (1) electron-rich phenol triflates require triphenylphosphine to undergo palladium-catalyzed cross-couplings; (2) in general, efficient reactions take place only when larger-than-usual amounts (10-15percent) of palladium are employed.On the reagent side, alkyl- (methyl only), allyl-, vinyl- and alkinylstannanes undergo efficient cross-couplings with the titlesubstrates.However, some limitations to this novel entry to 2-substituted resorcinols exist in regard to both substrates and reagents.Thus, conformationally rigid (hexasubstituted) aryl triflates behave poorly, demethylation being an important side reaction.Moreover, alkyl groups other than methyl cannot be introduced because β elimination occurs more rapidly.The potentially powerful synthesis of hindered biaryls has also been studied briefly.In the present conditions, the reaction appears to be limited by the presence of ortho substituents on the arylstannane moiety.
4. Synthese von Plectranthonen, diterpenoiden Phenanthren-1,4-chinonen
Kaliakoudas, Dimitrios,Eugster, Conrad Hans,Rueedi, Peter
, p. 48 - 62 (2007/10/02)
The following phenanthrene-1,4-diones have been synthesized by using the photocyclization of the corresponding highly substituted stilbenes as the key step: 3-hydroxy-5,7,8-trimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (1), (RS)-, (R)-, and (S)-2--1-methylethyl)acetate (2, 31, and 32, resp.), 3-hydroxy-7,8-dimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (3), 3-hydroxy-7,8,10-trimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (4), 5,7,8-trimethyl-2-(prop-2-enyl)phenanthrene-1,4-dione (17) and 3-hydroxy-2-methylphenanthrene-1,4-dione (42).The quinones 1 and 3 proved to be identical with recently isolated plectranthons A and C.Compounds 2, 31, and 32 exhibited the same UV/VIS, IR, 1H-NMR and mass spectra as natural plectranthon B, but had different melting points.This might be due either to crystal modifications or to diastereoisomerism caused by the helical structure of the phenanthrene-1,4-dione skeleton.The spectral data of synthetic 4 were not compatible with those of natural plectranthon D for which structure 4 had been proposed based mainly on 1H-NMR arguments concerning the chemical shifts of H-C(9) and H-C(10) in 1-3.Extensive 1H-NMR investigations have now revealed that the currently stated assignments of the H-C(9)/H-C(10) AB system have to be reversed for highly substituted phenanthrene-1,4-diones: in the model compounds 2-methylphenanthrene-1,4-dione (41) and 2, H-C(10) resonates at lower field as expected (peri-position), whereas in the highly substituted congeners 1, 2, 3, 31, and 32, H-C(9) is shifted paramagnetically, a fact which had lead to the erroneous assignment of structure 4 for natural plectranthon D.
Palladium catalyzed cross-coupling of phenol triflates with organostannanes. A versatile approach for the synthesis of substituted resorcinol dimethyl ethers.
Martorell, Gabriel,Garcia-Raso, Angel,Saa, Jose M.
, p. 2357 - 2360 (2007/10/02)
2,6-Dimethoxy-substituted phenol triflates undergo efficient Pd(0) catalyzed cross coupling with organostannanes, thus providing an easy access to substituted resorcinol dimethyl ethers, a common building block of many aromatic polyketides.
