17145-95-8

Upstream product

• 64897-42-3 phenyl 2,4-dinitrophenyl carbonate 
• 150-76-5 4-methoxy-phenol 
• 17175-11-0 phenyl O‐(4‐nitrophenyl) carbonate 
• 1202680-24-7 phenyl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylate 
• 1885-14-9 phenyl chloroformate 
• 108-95-2 phenol 
• 63812-28-2 (Chloro-phenoxy-methylene)-dimethyl-ammonium; chloride 
• 351197-68-7 2-(p-methoxyphenoxy)-2-phenoxy-5,5-dimethyl-Δ³-1,3,4-oxadiazoline 
• 762-42-5 dimethyl acetylenedicarboxylate 

Relevant academic research and scientific papers

Alkyl and aryl 4,5-dichloro-6-oxopyridazin-1(6 H)-carboxylates: A practical alternative to chloroformates for the synthesis of symmetric and asymmetric carbonates

Symmetric and asymmetric carbonates were synthesized by using alkyl or aryl 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates. Five aryl 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates were converted into the corresponding diaryl carbonates in good to excellent yields by treatment with potassium carbonate in refluxing THF. When the 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates were treated with aliphatic or aromatic alcohols in the presence of potassium tert-butoxide in toluene at room temperature, they gave the corresponding symmetric or asymmetric carbonates in moderate to excellent yields. Alkyl and aryl 4,5-dichloro-6-oxopyridazin-1(6H)-carboxylates are therefore efficient, stable, and ecofriendly alternatives to chloroformates.

Synthesis of organic carbonates with alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates and ROH/AlCl3under ambient condition

We demonstrated the synthesis of organic carbonates using alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates and alcohol in the presence of aluminum chloride. Alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates were reacted with alcohol in the presence of AlCl3 in toluene at room temperature to afford the corresponding unsymmetric and symmetric organic carbonates in good to excellent yields. These are efficient and convenient processes. Alkyl/aryl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylates are solid, stable and non-toxic CO2/CO2R(Ar) source. It is noteworthy that the reaction is carry out under an ambient and acidic conditions, the easy-to prepare and readily available starting materials and the quantitative isolation of reusable 4,5-dichloropyridazin-3(2H)-one.

Kinetic investigation of the phenolysis of phenyl 4-nitrophenyl and phenyl 2,4-dinitrophenyl carbonates

The reactions of phenyl 4-nitrophenyl carbonate (PDNPC) and phenyl 2,4-dinitrophenyl carbonate (PDNPC) with a homogeneous series of phenoxide anions are subjected to a kinetic investigation in water at 25.0 °C, ionic strength 0.2 mol dm-3 (KCl). Under phenoxide or total phenol excess over the substrate all these reactions obey pseudo first-order kinetics and are first order in phenoxide. The Bronsted-type plots for the nucleophilic rate constants are linear with slopes 0.61 and 0.49 for the phenolysis of PNPC and PDNPC, respectively. The magnitude of these slopes and the absence of curvature in the Brnsted plot at pKa = 7.1 for the PNPC reactions are consistent with concerted mechanisms (one step) for both reaction series. PDNPC is more reactive than PNPC toward phenoxide nucleophiles; this can be explained by the presence of a second nitro group in PDNPC, which (i) leaves its carbonyl carbon more positively charged than that of PNPC, making the former a better electrophile, and (ii) makes 2,4-dinitrophenoxide a better leaving group than 4-nitrophenoxide. The larger nucleophilic rate coefficients found in this work relative to those obtained in the concerted phenolysis of 4-nitrophenyl and 2,4-dinitrophenyl methyl carbonates is explained by a stronger electron withdrawal from PhO compared to MeO. Comparison of the concerted phenolysis of PNPC with the stepwise reactions of quinuclidines with the same substrate indicates that substitution of a quinuclidino group in a zwitterionic tetrahedral intermediate by a phenoxy group greatly destabilises the intermediate.

Diaryloxycarbenes from oxadiazolines

Symmetric and unsymmetric 2,2-diaryloxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines were synthesized by oxidative cyclization of aryloxycarbonyl hydrazones of acetone with lead tetraacetate and subsequent treatment of the product mixture with a phenol in acidic solution. Thermolysis of the oxadiazolines in benzene solution at 110°C afforded carbonyl ylide intermediates that cyclize, in part, to the corresponding 2,2-diaryloxyoxirane intermediates. The oxiranes, which were not observed, are required to account for the 1,1-diaryloxy-2-methylpropenes (ketene acetals) that were isolated. Most of the carbonyl ylides fragment to acetone and diaryloxycarbenes. The latter form dimers (tetraaryloxyethenes) or they can be trapped with phenols to form orthoformates. Diphenoxycarbene was also trapped with dimethyl acetylenedicarboxylate (DMAD). The method appears to be the first for generating the parent diphenoxycarbene under relatively mild conditions in solution, and the only one to date for generating unsymmetrically substituted diaryloxycarbenes. Minor competing fragmentations of the oxadiazolines to 2-diazopropane and the appropriate diaryl carbonates, were also observed.

Mechanism of ipso aromatic substitution by reaction of aryloxy(methoxy)carbenes and diaryloxycarbenes with DMAD

Some aryloxy(methoxy)carbenes and diaryloxycarbenes attack dimethyl acetylenedicarboxylate (DMAD) with aryl group transfer to an alkyne carbon of DMAD. In this study diaryloxycarbenes with different aryl groups that could be transferred competitively, were generated in the presence of DMAD to probe for the mechanism of that ipso aromatic substitution. It was found that a para electron-withdrawing substituent, relative to an electron-donating substituent, facilitated migration of an aryl group. Mechanisms in accord with these findings involve initial nucleophilic attack by the carbene at an alkyne carbon of DMAD. That step is followed by either nucleophilic, ipso attack on the aromatic ring or by electron transfer, from the side chain of the aromatic ring into the ring itself.

The Reaction of N-Dichloromethylene-N,N-dimethylammonium Chloride (Vieche's Salt) with Thiophenols and Phenols: a Synthesis of Unsymmetrical Diaryl Carbonates

The reaction of N-dichloromethylene-N,N-dimethylammonium chloride (Viehe's salt) with various thiophenols and phenols is reported.The resulting intermediate salts are generally transformed by water or sodium hydrogen sulfide to thiocarbonates and thiocarbamates.An efficient synthesis of unsymmetrical diaryl carbonates is discussed.