20333-68-0

Upstream product

• 100-02-7 4-nitro-phenol 
• 1005-56-7 phenylcarbonochloridothioate 
• 1132-69-0 4-nitrophenyl chlorothionoformate 
• 108-95-2 phenol 
• 1124-32-9 lithium 4-nitrophenolate 
• 5070-14-4 bis(4-nitrophenyl) thionocarbonate 

Downstream Products

• 100-02-7 4-nitro-phenol 
• 14609-74-6 p-nitrophenolate 
• 82495-44-1 O-phenyl chlorothionoformate 
• 824-78-2 4-nitrophenol sodium salt 
• 2540-60-5 o-phenyl benzylcarbamothioate 

Relevant academic research and scientific papers

Concerted mechanisms of the reactions of phenyl and 4-nitrophenyl chlorothionoformates with substituted phenoxide ions

The title reactions are subjected to a kinetic study in 3% (v/v) dioxane in water, 25.0 °C, ionic strength 0.2 M (KC1). By following the reactions spectrophotometrically, pseudo-first-order rate coefficients (￡0bsd) are found under an excess of the nucleophile. Plots of ￡0bsd vs phenoxide anion concentration at constant pH are linear, with the slope (￡N) independent of pH. The Bro?nstedtype plots (log AN vs pKa of the phenols) are linear with slopes β= 0.55 and 0.47 for the reactions of the phenyl and the 4-nitrophenyl derivatives, respectively. These Bro?nsted slopes are in agreement with the ones found in the concerted reactions of the same nucleophiles with reactive phenyl esters and acetic anhydride in water. In contrast to the concerted mechanism of the title reactions that of the same substrates with secondary alicyclic amines is stepwise, which means that substitution of an amino moiety in a tetrahedral intermediate with a phenoxy group by another phenoxy group destabilizes the intermediate to the point that it no longer exists.

DIRECT CONVERSION OF PHENOLS INTO AMIDES AND ESTERS OF BENZOIC ACID

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.

Radical OfC transposition: A metal-free process for conversion of phenols into benzoates and benzamides

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.

Alkaline hydrolysis of Y-substituted phenyl phenyl thionocarbonates: Effect of changing electrophilic center from C=O to C=S on reactivity and mechanism

Second-order rate constants (kOH-) have been measured spectrophotometrically for reactions of Y-substituted phenyl phenyl thionocarbonates (4a-i) with OH- in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 °C. The ksu

Radical 1,2-o→c transposition for conversion of phenols into benzoates by o-neophyl rearrangement/fragmentation cascade

Figure Presented Radical merry-go-round! Diaryl thiocarbonates, available in a single step from phenols, can be directly transformed into benzoates by a new radical cascade that transposes O and C atoms at the aromatic core. The cascade bypasses the common Barton McCombie fragmentation in favor of the usually unfavorable O-neophyl rearrangement, which is rendered irreversible and efficient by a highly exothermic C-S bond scission in the O-centered radical (see scheme; FG = functional group).

Kinetic study of the phenolysis of bis(4-nitrophenyl) carbonate, bis(4-nitrophenyl) thionocarbonate, and methyl 4-nitrophenyl thionocarbonate

The reactions of a homogeneous series of phenols with bis(4-nitrophenyl) carbonate (BNPC), bis-(4-nitrophenyl) thionocarbonate (BNPTOC), and methyl 4-nitrophenyl thionocarbonate (MNPTOC) are subjected to a kinetic investigation in water, at 25.0 °C and ionic strength of 0.2 M (KCl). Under excess of phenol over the substrate, all the reactions obey pseudo-first-order kinetics and are first order in phenoxide anion. The reactions of BNPC show a linear Broensted-type plot with slope β=0.66, consistent with a concerted mechanism (one step). In contrast, those of BNPTOC and MNPTOC show biphasic Broensted-type plots with slopes β=0.30 and 0.44, respectively, at high pKa, and β=1.25 and 1.60, respectively, at low pKa, consistent with stepwise mechanisms. For the reactions of both thionocarbonates, the pKa value at the center of the BrSnsted plot (pKa0) is 7.1, which corresponds to the pKa of 4-nitrophenol. This confirms that the phenolyses of the thionocarbonates are stepwise processes, with the formation of an anionic tetrahedral intermediate. By the comparison of the kinetics and mechanisms of the title reactions with similar reactions, the following conclusions can be drawn: (i) Substitution of S- by O- in an anionic tetrahedral intermediate (T-) destabilizes it. (ii) The change of MeO by 4-nitrophenoxy in T- results in an increase of both the rate constant and equilibrium constant, for the formation ofT-, and also in an enlargement of the rate coefficient for the expulsion of 4-nitrophenoxide from T-. (iii) Substitution of an amino group in a tetrahedral intermediate by ArO destabilizes it. (iv) Secondary alicyclic amines and other amines show greater reactivity toward MNPTOC than isobasic phenoxide anions.

Kinetics and Mechanism of the Aminolysis of Phenyl and Methyl 4-Nitrophenyl Thionocarbonates

The reactions of secondary alicyclic amines with the title substrates are subjected to a kinetic study in aqueous solution, 25.0°C, ionic strength 0.2 (KCl), by following spectrophotometrically the release of 4-nitrophenoxide ion. Under amine excess, pseu