14549-38-3Relevant articles and documents
Rapid Multigram-Scale End-to-End Continuous-Flow Synthesis of Sulfonylurea Antidiabetes Drugs: Gliclazide, Chlorpropamide, and Tolbutamide
Sagandira, Cloudius R.,Watts, Paul
supporting information, (2021/12/02)
A multigram-scale robust, efficient, and safe end-to-end continuous-flow process for the diabetes sulfonylurea drugs gliclazide, chlorpropamide, and tolbutamide is reported. The drugs were prepared by the treatment of an amine with a haloformate affording carbamate, which was subsequently treated with a sulfonamide to afford sulfonylurea. Gliclazide was obtained in 87% yield within 2.5 minutes total residence time with 26 g/h throughput; 0.2 kg of the drug was produced in 8 hours of running the system continuously. Chlorpropamide and tolbutamide were both obtained in 94% yield within 1 minute residence time with 184-188 g/h throughput; 1.4-1.5 kg of the drugs was produced in 8 hours of running the system continuously. N-Substituted carbamates were used as safe alternatives to the hazardous isocyanates in constructing the sulfonyl urea moiety.
Aminolyses of 4-nitrophenyl phenyl carbonate and thionocarbonate: Effect of modification of electrophilic center from C=O to C=S on reactivity and mechanism
Um, Ik-Hwan,Kim, Eun Young,Park, Hye-Ran,Jeon, Sang-Eun
, p. 2302 - 2306 (2007/10/03)
A kinetic study is reported for nucleophilic substitution reactions of 4-nitrophenyl phenyl carbonate (5) and 4-nitrophenyl phenyl thionocarbonate (6) with a series of primary amines. The thiono compound 6 is less reactive than its oxygen analogue 5 toward strongly basic amines but is more reactive toward weakly basic CF3CH2NH2. The Bronsted-type plots obtained from the aminolyses of 5 and 6 are curved downwardly. The reactions are proposed to proceed through a stepwise mechanism with a change in the RDS on the basis of the curved Bronsted-type plots. The microscopic rate constants (k1 and k2/k-1 ratio) associated with the current aminolyses are consistent with the proposed reaction mechanism. The replacement of the C=O bond in 5 by a polarizable C=S group results in a decrease in the k1 value but an increase in the k2/k-1 ratio. Besides, such a modification of the electrophilic center causes a decrease in pKac, defined as the pKa at the curvature center of curved Bronsted-type plots, but does not alter the reaction mechanism. The larger k 2/k-1 ratio for the reactions of 6 compared to those of 5 is proposed to be responsible for the decreased pKac value.
Preparation and applications of a polymer-supported phosphoryl azide
Lu, Yuhua,Taylor, Richard T.
, p. 9267 - 9269 (2007/10/03)
A polymer-supported diphenylphosphoryl azide was prepared. This polymer-supported version of DPPA is useful due to its lower toxicity, moisture tolerance and ease of workup after reaction. The synthetic application of this solid-phase reagent was explored by conversion of a variety of carboxylic acids to urethanes and ureas through Curtius rearrangement reactions. Carboxylic acids bearing different functional groups (aromatic, aliphatic and heterocyclic carboxylic acids) were subjected to the reaction. The corresponding products were isolated with satisfactory yields.
