- Efficient demethylation of aromatic methyl ethers with HCl in water
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A green, efficient and cheap demethylation reaction of aromatic methyl ethers with mineral acid (HCl or H2SO4) as a catalyst in high temperature pressurized water provided the corresponding aromatic alcohols (phenols, catechols, pyrogallols) in high yield. 4-Propylguaiacol was chosen as a model, given the various applications of the 4-propylcatechol reaction product. This demethylation reaction could be easily scaled and biorenewable 4-propylguaiacol from wood and clove oil could also be applied as a feedstock. Greenness of the developed methodversusstate-of-the-art demethylation reactions was assessed by performing a quantitative and qualitative Green Metrics analysis. Versatility of the method was shown on a variety of aromatic methyl ethers containing (biorenewable) substrates, yielding up to 99% of the corresponding aromatic alcohols, in most cases just requiring simple extraction as work-up.
- Bomon, Jeroen,Bal, Mathias,Achar, Tapas Kumar,Sergeyev, Sergey,Wu, Xian,Wambacq, Ben,Lemière, Filip,Sels, Bert F.,Maes, Bert U. W.
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supporting information
p. 1995 - 2009
(2021/03/26)
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- Substituted 1,2,3,4-tetrahydroquinolin-6-yloxypropanes as β3-adrenergic receptor agonists: Design, synthesis, biological evaluation and pharmacophore modeling
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In search of potent β3-adrenergic receptor agonists, a series of novel substituted 1,2,3,4-tetrahydroquinolin-6-yloxypropanes has been synthesized and evaluated for their β3-adrenergic receptor agonistic activity (ranging from -17.73% to 90.64% inhibition at 10 μM) using well established Human SK-N-MC neuroblastoma cells model. Four molecules viz. 11, 15, 22 and 23 showed β3-AR agonistic IC50 value of 0.55, 0.59, 1.18 and 1.76 μM, respectively. These four candidates have been identified as possible leads for further development of β3-adrenergic receptor agonists for obesity and Type-II diabetes pharmacotherapy. The free OH and NH functions are found to be essential for β3-adrenergic receptor agonistic activity. Among the synthesized β3-adrenergic receptor agonists having 1,2,3,4-tetrahydroquinoline scaffold, the N-benzyl group is found to be superior over N-arylsulfonyl group. A putative pharmacophore model has been modeled considering the above four active molecules which distinguishes well between the active and inactive molecules.
- Shakya, Neeraj,Roy, Kuldeep K.,Saxena, Anil K.
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experimental part
p. 830 - 847
(2009/07/25)
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- Fe-HCl: An efficient reagent for deprotection of oximes as well as selective oxidative hydrolysis of nitroalkenes and nitroalkanes to ketones
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Fe-HCl mixture was found to selectively perform oxidative hydrolysis of the nitroalkenes 1a-j and nitroalkanes 2a-j to the ketones 3a-j. Also, the reagent was observed to deprotect the oximes 7a-j to carbonyl compounds 8a-j in excellent yields.
- Pradhan, Prasun K.,Dey, Sumit,Jaisankar, Parasuraman,Giri, Venkatachalam S.
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p. 913 - 922
(2007/10/03)
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- Mass spectrometric investigations on phenylacetic acid derivatives, IV: Loss of ortho-substituents from ionized phenyl-2-propanones upon electron impact
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In the gas phase, the phenyl-2-propanone molecules 2a-4a lose upon electron impact chloro-, bromo-, and iodo-radicals specifically at the orthopOsition of the phenyl group giving rise to strong (M-Hal.)+-ions (70/12 eV; 1st and 2nd FFR) of identical structure as confirmed by their MIKE-CAD-spectra. The daughter ions at m/z 133 from o-chlorophenyl-2-propanone (2a) and 2,2-dimethyl-2,3-dihydro[b]furane (11) are structurally similar but not identical (similarity index 99.8). The collisionally activated (2nd FFR) (M-Br.)+-ions from o-bromophenyl-2-propanone (3a) and 1-bromo-1-phenyl-2-propanone (12) produce virtually congruent spectra. The most impOrtant subsequent fragmentation of the (M-Hal-)+-ions from 2a-4a is the loss of CO which incorporates the C-atom of the carbonyl group exclusively (13C labelling). Mechanistic aspects of the fragmentation sequences are discussed (Figs. 5 and 8).
- Striegel,Mayer,Wiegrebe,Schlunegger,Siegrist,Aebi
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p. 751 - 760
(2007/10/02)
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- Process for producing phenylacetones
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A phenylacetone or its derivative having the general formula (I): STR1 wherein X, Y, and Z are independently a hydrogen atom, a hydroxyl group, a halogen atom, a nitro group, an amino group, a lower alkyl group having 1 to 6 carbon atoms, a lower alkoxy group having 1 to 6 carbon atoms, or a benzyloxy group and any two substituents of X, Y, and Z may form, together with the benzene ring, a heterocycling ring having 5 to 7 members including 1 or 2 oxygen atoms is produced at a high yield and a high selectivity by reacting a 3-phenylpropylene or its derivative having the general formula (II): STR2 wherein X, Y, and Z are as defined above, with an alkyl nitrite having the general formula (III): wherein R is an aliphatic, aromatic, or alicyclic saturated or unsaturated hydrocarbon group in the presence of (a) water, (b) an alcohol, (c) a palladium catalyst, and (d) an optional amine or copper compound, or by reacting the above-mentioned 3-phenylpropylene or its derivative with the above-mentioned alkyl nitrite in the presence of (a) an alcohol, (b) a palladium catalyst and (c) an optional amine or copper compound to form 1-phenyl-2,2-dialkoxypropane or it derivative having the general formula (IV): STR3 wherein X, Y, Z and R are as defined above, followed by hydrolyzing the reaction product.
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- Secondary amines
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Compounds of formula (II): STR1 or salt thereof; wherein R1 is hydrogen or methyl, R2 is hydrogen or methyl, R3 is hydrogen, C1-12 straight or branched alkyl, C3-10 cycloalkyl, phenyl(C1-4)-alkyl or benzyl optionally substituted by C1-4 alkyl, C1-4 alkoxy or halogen; R4 is hydrogen, halogen, hydroxy, C1-4 alkyl or C1-4 alkoxy, R5 is hydrogen or fluorine, R6 is hydrogen or fluorine, R7 is halogen; and n is 1 or 2, have anti-obesity and/or anti-hyperglycaemic activity.
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- Reactions of 4-Substituted-2'-Halogenoacetophenones with Grignard Reagents
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The initial reaction of 4-substituted 2'-halogenoacetophenones with an excess of methyl Grignard reagent is shown to be an attack at the 1'-carbonyl to form a halohydrin salt.The various reactions which then follow are substituent dependent.In the 4-hydroxy case the only product is 1-(4-hydroxyphenyl)-2-methylpropan-2-ol (13) which arises via a -aryl shift with simultaneous elimination of magnesium halide.When the substituent is 4-methoxy, a second pathway becomes important involving epoxide formation and a subsequent -hydride migration to the benzylic position, or attack of the Grignard reagent at the benzylic carbon of the epoxide.When the substituent is 4-bromo, the reaction proceeds exclusively via the epoxide and, following a -hydride shift, leads to the isomeric butanols (33) and (34).The reasons underlying such diversity of reactivity are discussed.
- Crombie, Leslie,Hardy, Robert,Knight, David W.
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p. 1373 - 1380
(2007/10/02)
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- REACTION OF NITROOLEFINS WITH RANEY NICKEL AND SODIUM HYPOPHOSPHITE. A MILD METHOD FOR CONVERTING NITROOLEFINS INTO KETONES (OR ALDEHYDES).
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Nitroolefins are converted into the corresponding saturated ketones or aldehydes in high yield by treatment with Raney nickel and sodium hypophosphite in aqueous ethanol at pH 5.
- Monti, Diego,Gramatica, Paola,Speranza, Giovanna,Manitto, Paolo
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p. 417 - 418
(2007/10/02)
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