51676-65-4

Upstream product

• 623-79-0 O,S-Diethyl dithiocarbonate 
• 70-34-8 2,4-Dinitrofluorobenzene 
• 140-89-6 potassium ethyl xanthogenate 
• 97-00-7 1-chloro-2,4-dinitro-benzene 

Downstream Products

• 56525-82-7 1-pyrrolidinecarbothioic acid O-ethyl ester 
• 2218-96-4 2,4-dinitrothiophenol 
• 56525-81-6 1-piperidinecarbothioic acid O-ethyl ester 
• 56437-88-8 2,4-dinitrobenzenethiolate anion 
• 936-64-1 morpholinyl thiocarbamate 
• 64-17-5 ethanol 
• 55365-85-0 O-Ethyl N-Butylthiocarbamate 
• 848189-72-0 dithiocarbonic acid O-ethyl ester-S-(3-chloro-phenyl ester) 

Relevant academic research and scientific papers

Hydrolysis and aminolysis of alkyl xanthate esters and cellulose analogues

The hydrolysis and aminolysis of a series of S-substituted O-alkylxanthate esters was studied in 20% v/v aqueous methanol at 35°C. The pH-rate profiles of the hydrolyses showed water and hydroxide-ion-catalyzed reactions. The reaction of 2,4-dinitrophenyl cellulose xanthate (CelXDNP) and p-nitrobenzyl cellulose xanthate (CelXNB) with polyalanine and lysozyme produced a covalent bond between the polypeptide and the cellulose matrix, as shown by solid-state 13C NMR. However, the nature of the bonding could not be identified. The reaction of nucleophiles (H2O, OH-, RNH2) and xanthic esters was consistent with an addition-elimination mechanism through a tetrahedral intermediate. Bronsted plots against the pKa of the nucleophile (βnu) or the nucleofuge of the substrate (βlg) were used to characterize the rate-determining step. The pKa values of the nucleophiles ranged between -1.74 and 15.74, and for the nucleofuges, they were in the range of 10.50-0.92. For nucleophiles with pKa values up to about 10, βlg was 0.10-0.15, and βnu changed from 0.48 to 0.35 for the strongest electron-withdrawing nucleofuge. It was concluded that the water-catalyzed hydrolyses, and also aminolyses with moderately basic amines, occur with rate-determining formation of the tetrahedral intermediate. For strong bases such as hydroxide ion, the disappearance of the intermediate becomes the slowest step. The reaction of cellulose xanthic esters with external nucleophiles as hydroxide ion and amines shows simple first-order kinetics and is slower than alkyl or sugar xanthates, probably due to the diffusion effect through the tight cybotactic region of cellulose.

Kinetics and Mechanism of the Aminolysis of 2,4-Dinitrophenyl and 2,4,6-Trinitrophenyl O-Ethyl Dithiocarbonates

The reactions of a series of secondary alicyclic amines with the title substrates (DNPDTC and TNPDTC) are subject to a kinetic study in water at 25.0 deg C, ionic strength 0.2 M (KCl).The reactions are first order in both the amine and the substrate.The Broensted-type plots obtained are nonlinear and are explained by a stepwise mechanism through a zwitterionic tetrahedral intermediate (T+/-), although a concerted process is not rigorously excluded for the reactions of the less basic amines with TNPDTC.An equation is reported which describes the dependence of the basicities of the amine and leaving group on the nucleofugality ratio of these groups from T+/- (k-1/k2).This equation satisfactorily predicts the pKa values at the Broensted breaks (pKa0).The experimental pKa0. values found in the present reactions correlate well with those in the aminolysis of p-nitro- and unsubstituted phenyl O-ethyl dithiocarbonates.The values of both k-1 and k2 are larger in the reactions of phenyl O-ethyl dithiocarbonate than in the aminolysis of phenyl dithioacetate due to the additional push exerted by EtO in T+/-.The T+/- formed in the aminolysis of DNPDTC is less unstable than that in the aminolysis of S-(2,4-dinitrophenyl)O-ethyl thiocarbonate (whose mechanism is concerted), and this is attributed to a smaller ability of S- in T+/- to form a double bond and expel a nucleofuge.