1565-76-0Relevant articles and documents
Photoinduced electron-transfer substitution reactions via unusual charge-transfer intermediates
Miller, John B.,Salvador, James R.
, p. 435 - 442 (2002)
The photoinduced substitution reactions of halogenated alkanes (1-haloadamantanes, 1-haloronorbornanes, menthyl chloride) with a homologous series of amines or alcohols (methylamine, 2-methyl-2-aminopropane, methanol, or 2-methyl-2-propanol) to form the corresponding alkane-substituted amines or ethers and HCl were investigated. The geometry of the bridgehead carbons made SN2 reactions impossible. Nonpolar reaction conditions were employed which made classical and nonclassical carbocation SN1 reaction pathways unlikely. The reaction rates were measured. Trapping experiments indicated that free radical reactions were uninvolved in the substitution product formation. A novel, photoinduced electron-transfer reaction mechanism involving a charge-transfer intermediate is proposed to explain the observed production of secondary amines and ethers. The excitation wavelength dependence (action spectrum) was measured and found to be comparable to the ultraviolet absorption spectra of the charge-transfer complexes. The stereochemical implications of the reaction mechanism were investigated. The formation of the methyl ether of (1R,2S,5R)-menthol was the only organic reaction product observed in the photoreaction between (1R,2S,5R)-menthyl chloride and methanol.
Insecticidal activity of menthol derivatives against mosquitoes
Samarasekera, Radhika,Weerasinghe, Indira S.,Hemalal, K.D. Patrick
, p. 290 - 295 (2008)
BACKGROUND: The insecticidal activity of essential oil of Mentha piperita L. emend. Huds. against local mosquitoes as disease vectors was recognized and found to be due to the presence of menthol, which is the major aroma compound of the oil. The minor compounds of the oil, i.e. menthone, β-caryophyllene, menthyl acetate, limonene, α-pinene and pulegone, showed either less or no activity against the mosquitoes tested. L-Menthol derivatives were synthesized and their knockdown effect and mortality were evaluated against local mosquitoes of Culex quinquefasciatus Say, Aedes aegypti L. and Anopheles tessellatus Theobald as disease vectors. This is the first report of mosquitocidal activity of menthol and its derivatives against Cx. quinquefasciatus, Ae. aegypti and An. tessellatus. RESULTS: Derivative synthesis followed by structure-activity relationship studies identified several derivatives, i.e. menthyl chloroacetate, menthyl dichloroacetate, menthyl cinnamate, menthone glyceryl acetal, thymol, α-terpineol and mugetanol, with enhanced mosquitocidal activity against Cx. quinquefasciatus, Ae. aegypti and An. tessellatus relative to the parent compound L-menthone. CONCLUSION: In ester derivatives of L-menthol the optimum activity is dependent on the size and shape of the ester group and the presence of chlorine atoms in the ester group. In structurally related derivatives of L-menthol the optimum activity is dependent on the aromaticity, the degree of unsaturation, the position of the hydroxy group and the type of functional group.
Rapid probing of the reactivity of P450 monooxygenases from the CYP116B subfamily using a substrate-based method
Li, Ren-Jie,Xu, Jian-He,Yin, Yue-Cai,Wirth, Nicolas,Ren, Jiang-Meng,Zeng, Bu-Bing,Yu, Hui-Lei
supporting information, p. 8928 - 8934 (2016/10/13)
Developing a detailed understanding of the reactivity of self-sufficient Type IV P450 monooxygenases, four types of O-methylated substrates were designed as probes, including monoterpenes, cycloalkanes, aromatic compounds and steroids, and the efficiency of their oxyfunction was determined using a colorimetric assay which was based on the reaction between the enzymatic demethylation product, formaldehyde, and Purpald dye. The activity-based fingerprints of new P450RpMO, P450ArMO and P450CtMO (CYP116B members) indicated that CYP116B P450s preferentially oxidize substrates with aromatic components. Moreover, the hydroxylated products were detected based on the preference results. This rapid and efficient strategy, when coupled with GCMS, enables the exploration of the reactivity of other CYP116B members.
2,2,2-Trichloroethyl aryldiazoacetates as robust reagents for the enantioselective C-H functionalization of methyl ethers
Guptill, David M.,Davies, Huw M. L.
supporting information, p. 17718 - 17721 (2015/02/19)
A new class of reagents is described for C-H functionalization by means of C-H insertion using donor/acceptor-substituted rhodium(II) carbene intermediates. The 2,2,2-trichloroethyl aryl and heteroaryl diazoacetates, together with the dirhodium triarylcyclopropane carboxylate catalyst Rh2(R-BPCP)4, enabled the enantioselective intermolecular C-H functionalization of a range of methyl ethers with high levels of site selectivity and enantioselectivity.
Improved procedure for the synthesis of methyl ethers from alcohols
Rao, H. Surya Prakash,Senthilkumar,Reddy, D. Srinivasa,Mehta, Goverdhan
, p. 260 - 263 (2007/10/03)
Alcohols can be conveniently converted to the corresponding methyl ethers with methyl iodide in the presence of KOH under solvent-free conditions.
Chiral lithiomethyl ethers by DTBB-catalyzed chlorine-lithium exchange
Ortiz, Javier,Guijarro, Albert,Yus, Miguel
, p. 44 - 48 (2007/10/03)
The reaction of equimolecular amounts of enantiomerically pure (+)- or (-)- chloromethyl menthyl ethers 1. or the phenyl derivative (-)-4 and an electrophile [Me3SiCl, Bu'CHO, PhCHO, (CH2)4CO, Et2CO, PhCOMe, Ph2CO, HCONMe2, PhCH=NPh] with an excess of lithium powder (1:7 molar ratio) and a catalytic amount of DTBB (5 mol %) in THF at 0°C (Method A) leads, after hydrolysis, to the corresponding functionalized chiral ethers 2 and 5. The reaction can be also carried out in a two step process: tandem lithiation at -90°C followed by reaction with the electrophile (H2O, D2O) at the same temperature (Method B). When prochiral electrophiles are used (Bu'CHO, PhCHO. PhCOMe, PhCH=NPh), low asymmetric induction (1:2) is obtained. Springer-Verlag Iberica 1997.
Reaction of Grignard Reagents with Benzaldehyde, 2,2-Dimethylpropanal and Cinnamates of Chiral Alcohols in Chiral Solvents
Jalander, Lars,Strandberg, Rolf
, p. 15 - 20 (2007/10/02)
The asymmetric induction in a Grignard reaction carried out in (-)-1-isopropyl-2-methoxy-4-methylcyclohexane was higher than in the reaction carried out in (+)-1-methoxy-2-methylbutane.The chirality of the solvent contributed more than that of the reagent stereodifferentiation in the reaction of (+)-2-methylbutylmagnesium bromide with benzaldehyde in (+)-1-methoxy-2-methylbutane.
