- Tertiary thiols from allylic thiocarbamates by tandem enantioselective [3,3]-sigmatropic rearrangement and stereospecific arylation
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The synthesis of tertiary thiols in enantiomerically enriched form is accomplished by lithiation of enantiomerically enriched N-aryl allylic thiocarbamates. Formation of an allyllithium derivative promotes intramolecular N to C aryl migration to the posit
- Mingat, Gaelle,Maclellan, Paul,Laars, Marju,Clayden, Jonathan
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p. 1252 - 1255
(2014/03/21)
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- S-allyl thiocarbamates from allylic alcohols by in situ [3,3]-sigmatropic rearrangement of a thiocarbonyldiimidazole adduct
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Treatment of allylic alcohols with thiocarbonyldiimidazole generates an unstable O-allyl imidazolyl thione ester, which rearranges spontaneously and in high yield to the corresponding S-allyl imidazolyl thiol ester. Displacement of the imidazole by N-alky
- Mingat, Gaelle,Clayden, Jonathan
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p. 2723 - 2734
(2012/11/07)
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- Radical OfC transposition: A metal-free process for conversion of phenols into benzoates and benzamides
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We report a metal-free procedure for transformation of phenols into esters and amides of benzoic acids via a new radical cascade. Diaryl thiocarbonates and thiocarbamates, available in a single high-yielding step from phenols, selectively add silyl radicals at the sulfur atom of the CdS moiety. This addition step, analogous to the first step of the Barton-McCombie reaction, produces a carbon radical which undergoes 1,2 OfC transposition through an O-neophyl rearrangement. The usually unfavorable equilibrium in the reversible rearrangement step is shifted forward via a highly exothermic C-S bond scission in the O-centered radical, which furnishes the final benzoic ester or benzamide product. The metal-free preparation of benzoic acid derivatives from phenols provides a potentially useful alternative to metal-catalyzed carbonylation of aryl triflates.
- Baroudi, Abdulkader,Alicea, Jeremiah,Flack, Phillip,Kirincich, Jason,Alabugin, Igor V.
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experimental part
p. 1521 - 1537
(2011/06/11)
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- DIRECT CONVERSION OF PHENOLS INTO AMIDES AND ESTERS OF BENZOIC ACID
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A method is provided for the preparation of an aromatic carboxylic acid aryl ester or an N-aryl aromatic carboxamide. The method comprises contacting an O,O-diaryl thiocarbonate or an O-aryl-N-aryl thiocarbamate with a reactant that regioselectively reacts with sulfur, which contact causes an O-neophyl rearrangement, thereby forming either the aromatic carboxylic acid aryl ester or the N-aryl aromatic carboxamide, respectively.
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Page/Page column 15
(2011/10/12)
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- Novel [2-(4-piperidinyl)ethyl](thio)ureas: Synthesis and antiacetylcholinesterase activity
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A series of 1-ar(o)yl-3-[2-(1-benzyl-4-piperidinyl)ethyl](thio)urea derivatives was synthesized and evaluated for antiacetylcholinesterase activity. Most aroyl(thio)urea derivatives showed potent inhibitory activity in the sub-micromolar range. A comparable potency was obtained with the aryl(thio)urea analogues by replacing the phenyl with a 2-pyridyl group. The substituted guanidine variations proved to be almost inactive whereas the nitroethylene analogues appeared to be quite efficient. These results were interpreted in terms of the preferential cis-trans conformation of the aroyl(thio)urea and 2-pyridyl(thio)urea moieties involving the existence of hydrogen bonding. In vivo experiments showed that compound 7m had maximal antiamnestic activity at 0.03 mg/kg with a therapeutic ratio greater than 1000, while cholinergic side effects were only seen at doses 100-fold the maximally effective antiamnestic dose. Compound 7m represents a potentially interesting antidementia agent.
- Vidaluc,Calmel,Bigg,Carilla,Stenger,Chopin,Briley
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p. 689 - 695
(2007/10/02)
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- A NEW SYNTHETIC PROCEDURE FOR THE CONVENIENT PREPARATION OF THIOCARBAMOYL CHLORIDES AND THE NOVEL BIS-THIOCARBAMOYL CHLORIDES
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Treatment of N-silylamines with excess thiophosgene affords thiocarbamoyl chlorides in good yields and excellent purity.This method was also suitable for preparing the first bis-thiocarbamoyl chlorides from N,N'-bis(trimethylsilyl)-diamines.Bis-thiocarbam
- Skorini, Samal Jens i,Senning, Alexander
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p. 539 - 542
(2007/10/02)
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