34257-56-2Relevant academic research and scientific papers
Oxidation of Alkylthio Substituted Tricarbonyl(η6-arene)chromium(0) Complexes to Alkylsulfinyl Substituted Tricarbonyl(η6-arene)chromium(0) Complexes
Perez-Encabo, Alfonso,Perrio, Stephane,Slawin, Alexandra M. Z.,Thomas, Susan E.,Wierzchleyski, Adam T.,Williams, David J.
, p. 629 - 642 (2007/10/02)
Dimethyldioxirane efficiently oxidises tricarbonylchromium(0) complexes of alkylthio substituted arenes to tricarbonylchromium(0) complexes of alkylsulfinyl substituted arenes.The diastereoselectivity of oxidation of ortho substituted complexes, which was determined by inter alia X-ray crystal structure analyses of tricarbonyl6-1-methoxy-2-(methylsulfinyl)benzene>-chromium(0) 20x, 6-1-(tert-butylsulfinyl)-2-methoxybenzene>tricarbonylchromium(0) 23x and tricarbonyl6-1-(ethylsulfinyl)-2-methoxybenzene)chromium(0) 21y, is dependent on the alkylthio substituent and is reversed when this substituent is changed from methylthio to tert-butylthio.
Metallation reactions. XX. Regioselective metallation of (alkylthio)methoxybenzenes by superbases versus organolithium compounds
Cabiddu,Fattuoni,Floris,Gelli,Melis
, p. 4965 - 4974 (2007/10/02)
(Alkylthio)methoxybenzenes have been metallated using two different metallating agents. The results show that sometimes superbases and butyllithium do not functionalize the same sites. Superbases monometallate the thiomethylic carbon of meta and para (methylthio)methoxybenzenes. The same substrates on the other hand are metallated by butyllithium in ortho to the methoxy group. One-step dimetallation performed with either superbases or butyllithium occurs at the thiomethylic carbon at the aryl carbon ortho to the methoxy group. Two consecutive one-pot monometallations of the para isomer (1c) with superbases occur at the thiomethylic carbon and at the annular carbon ortho to the methoxy group, in this order. A similar procedure with butyllithium metallates the two ortho positions to the methoxy group. Monometallation of (ethylthio) derivative (1d) yields, products substituted in ortho to the methoxy group using, either superbases or butyllithium. Dimetallation of this compound always substitutes the hydrogen ortho to the methoxy group and a thiomethylenic hydrogen.
METALATION REACTIONS. XIV. REGIOSPECIFIC PREPARATION OF POLYSUBSTITUTED BENZENES VIA MONO- OR DI-LITHIATION REACTIONS OF AROMATIC THIOETHERS
Cabiddu, Salvatore,Fattuoni, Claudia,Floris, Costantino,Gelli, Gioanna,Melis, Stefana,Sotgiu, Francesca
, p. 861 - 884 (2007/10/02)
The preparation of polyfunctionalized aromatic thioethers either by one-step dilithiation or by two successive one-flask monometalation reactions is described.By acting on 1 two equal or different electrophiles one on the thiomethyl group and one in the ortho-position with respect to it are introduced; by acting on 11 and on 35 the substitution involves the thiomethyl carbon atom and that in the ortho-position with respect to the alkoxy group.In the case of the homologeous isopropylthio (23) the substitution involves the two aryl carbon atoms in the ortho-position to both functions.In the case of the p-disubstituted isomers (49, 59) analogous behaviour to ortho isomers in one-step metalation reaction is observed, while the two hydrogen atoms in the ortho-positions to the methoxy group are substituted when two successive monometalations are employed.The metalation of 40 results low selective.The behaviour of 79 and 93 is analogous to 1, while 72, 88 and 96 undergo only one-step monometalation reactions.
ETUDE DES REACTIONS DE SRN1-PARTIE 10 ACTION DE SULFANIONS SUR LES HALOGENURES D'ARYLE FONCTIONNALISES. SYNTHESE DIRECTE DE BENZOTHIOPHENES ET THIENOPYRIDINES
Beugelmans, Rene,Bois-Choussy, Michele,Boudet, Bernard
, p. 4153 - 4162 (2007/10/02)
Functionalized aromatic halides Ar1XY (Ar1=C6H4, Y=OCH3,CONH2,CN,COCH3,CHO,COC6H5) undergo SRN1 reactions with sulphur anions -SR, either simple (R=C2H5,CH2C6H5) or functionalized (R=(CH2)2OH,(CH2)2CO2Et,CH2CO2Et).Products Ar1YS- formed from the fragmentation of the radical anion Ar1YSR- are related to the redox potential of the aryl moiety Ar1Y and with the energy of the bond S-R.In the heterocyclic series (Ar2=pyridine, Ar3=quinoline) a similar relationship appears but a competitive SN(AR) reaction occurs for pyridine substrates bearing an electron withdrawing group.A direct synthesis of benzothiophen via SRN1 reaction and an improved synthesis of thienopyridines based on the SN(Ar) reaction are reported.
SELECTIVE CLEAVAGE OF THE CARBON-SULPHUR AND CARBON-OXYGEN BONDS IN METHOXYTHIOANISOLES
Testaferri, L.,Tiecco, M.,Tingoli, M.,Chianelli, D.,Maiolo, F.
, p. 2721 - 2724 (2007/10/02)
Selective cleavage of thioether or ether functions in methoxythioanisoles in hexamehtylphosphoramide (HMPA) with sodium gives methoxythiophenols by cleavage of the carbon-sulphur bond.Reactions with sodium isopropanethiolate give instead the thiomethoxyphenols by dealkylation of the methoxy function.When the methoxythioanisoles were treated first with sodium isopropanethiolate and then with sodium complete dealkylation was achieved with formation of mercaptophenols.The present methods have considerable advantages over existing procedures for the synthesis of methoxythiophenols, thiomethoxyphenols and mercaptophenols.The mechanistic implications of the reactions investigated are also discussed.
