3848-42-8

Upstream product

• 5070-13-3 bis-(p-nitrophenyl) carbonate 
• 106-49-0 p-toluidine 
• 100-02-7 4-nitro-phenol 
• 622-58-2 p-Tolylisocyanate 
• 7693-46-1 4-Nitrophenyl chloroformate 
• 701208-43-7 4-nitrophenyl 2,4-dinitrophenyl carbonate 
• 104-87-0 4-methyl-benzaldehyde 

Downstream Products

• 100-02-7 4-nitro-phenol 
• 5456-97-3 N-butyl-4-methylbenzamide 
• 132931-80-7 3-Benzyl-3-methyl-1-(4-tolyl)urea 
• 622-58-2 p-Tolylisocyanate 
• 35580-58-6 C₁₁H₁₅N₃O₃ 
• 946132-40-7 O-(1-naphthylmethyleneimino)-N-(4-tolyl)carbamate 
• 79491-05-7 4-(4-methylphenyl)-1,2,4-triazolidine-3,5-dione 
• 106-49-0 p-toluidine 
• 132931-79-4 N'-(4-methylphenyl)-N,N-dipropan-2-ylurea 

Relevant academic research and scientific papers

Anilinolysis of reactive aryl 2,4-dinitrophenyl carbonates: Kinetics and mechanism

The reactions of a series of anilines with phenyl 2,4-dinitrophenyl (1), 4-nitrophenyl 2,4-dinitrophenyl (2), and bis(2,4-dinitrophenyl) (3) carbonates are subjected to a kinetic investigation in 44 wt% ethanol-water, at 25.0 ± 0.1°C and an ionic strength of 0.2 M. Under amine excess pseudo-first-order rate coefficients (kobs) are obtained. Plots of kobs against free amine concentration at constant pH are linear, with slopes kN. The BrAnsted plots (log kN vs. anilinium pKa) for the anilinolysis of 1-3 are linear, with slope (β) values of 0.52, 0.61, and 0.63, respectively. The values of these slopes and other considerations suggest that these reactions are ruled by a concerted mechanism. For these reactions, the kN values follow the reactivity sequence: 3 > 2 > 1. Namely, the reactivity increases as the number of nitro groups attached to the nonleaving group increases. Comparison of the reactions of this work with the stepwise pyridinolysis of carbonates 1-3 indicates that the zwitterionic tetrahedral intermediate (T±) formed in the pyridinolysis reactions is destabilized by the change of its pyridino moiety by an isobasic anilino group. This is attributed to the superior leaving ability from the T± intermediate of anilines, relative to isobasic pyridines, which destabilize kinetically this intermediate. The kN values for the anilinolysis of carbonates 1-3 are similar to those found in the reactions of these carbonates with secondary alicyclic amines. With the kinetic data for the anilinolysis of the title substrates and 4-methylphenyl and 4-chlorophenyl 2,4-dinitrophenyl carbonates, a multiparametric equation is derived for log kN as a function of the pKa of the conjugate acids of anilines and nonleaving groups.

A novel naphthylmethyleneimino-type photocleavable protecting group for primary amines

A novel naphthylmethyleneimino-type protecting group for aliphatic and aromatic primary amines including α-amino acids was devised and its introduction was accomplished in good to excellent yields. This type of protecting group was found to be cleanly removed photochemically to regenerate the primary amines in good to high yields, regardless of steric and electronic properties. Georg Thieme Verlag Stuttgart.

Novel and efficient synthesis of 4-substituted-1,2,4-triazolidine-3,5- diones from anilines

A simple and efficient three-step synthetic procedure for the preparation of 4-substituted phenyl derivatives of 1,2,4-triazolidindiones (urazoles), starting from anilines, has been developed. In this method, aniline derivatives were reacted with 4-nitrophenyl chloroformate to provide corresponding carbamate derivatives. In the second step, semicarbazide derivatives were prepared from these carbamates by reaction with ethyl carbazate. The cyclization reaction of corresponding semicarbazides furnished 1,2,4-triazolidindiones in high yields. Copyright Taylor & Francis Group, LLC.

Kinetics and mechanism of the anilinolysis of aryl 4-nitrophenyl carbonates in aqueous ethanol

The reactions of anilines with 4-nitrophenyl, 4-methylphenyl, and 4-chlorophenyl 4-nitrophenyl carbonates (BNPC, MPNPC and ClPNPC, respectively) are studied kinetically in 44 wt % ethanol-water, at 25.0 °C, with an ionic strength of 0.2 M (KCl). Plots of kobsd vs [amine] are linear, with the slopes (kN) independent of pH. The Bronsted-type plots (log kN vs pKa of conjugate acids of anilines) are linear, with slopes β = 0.65, 0.85, and 0.78 for the reactions of anilines with BNPC, MPNPC, and ClPNPC, respectively. The values of the slopes for the two latter reactions are in accordance with those obtained in stepwise mechanism where breakdown to product of a zwitterionic tetrahedral intermediate is the rate-determining step. On the other hand, the β value for the reactions of BNPC is at the upper limit of those found for concerted mechanisms. The kinetic results for the reactions of anilines with BNPC correlates well with those for the concerted reactions of the same amines with 4-methylphenyl and 4-chlorophenyl 2,4-dinitrophenyl carbonates: A plot of the calculated log k N values (through a multiple parametric equation) vs the experimental log kN values is linear with unity slope and zero intercept, which confirms the concerted mechanism for the latter three reactions.

Multilevel selectivity in the mild and high-yielding chlorosilane- induced cleavage of carbamates to isocyanates

The silane-induced cleavage of a series of N-p-tolylcarbamates and N- phenethylcarbamates to isocyanates has been investigated as a function of chlorosilane, carbamate substituent, and reaction conditions. Reaction yields were determined from the isolated ureas, which were formed by trapping the corresponding isocyanates with isobutylamine. Under room-temperature conditions, multilevel selectivity in carbamate activation has been demonstrated. This selectivity together with the generality of the methodology enhances the utility of carbamates as synthetic intermediates and protecting groups. To demonstrate the effectiveness of this selectivity, a series of biscarbamates were selectively monoactivated to isocyanates in excellent yields.

Kinetics and mechanism of the aminolysis of p-nitrophenyl N-phenylcarbamates

Kinetic studies of the reactions of p-nitrophenyl N-phenylcarbamates with benzylamines were carried out in acetonitrile at 25·0°C. Second-order (k2) and third-order (k3) rate constants were observed for all the Y-substituted carbamates except for Y=m Cl. The relatively large magnitude of ρx (for X-substituted benzylamines) and ρY together with a positive cross-interaction constant ρxy supports a stepwise mechanism involving rate-limiting breakdown of the zwitterionic tetrahedral intermediate T±. Kinetic isotope effect studies with deuterated benzylamine (XC6H4CH2ND2) indicate that in the base-catalyzed path, k3, rate-limiting deprotonation occurs at the amino group of benzylamine within the T± intermediate. The low ΔH≠ and ΔS≠ values for the k3 process are in accord with the proposed mechanism.