126401-65-8Relevant academic research and scientific papers
Formamides as Isocyanate Surrogates: A Mechanistically Driven Approach to the Development of Atom-Efficient, Selective Catalytic Syntheses of Ureas, Carbamates, and Heterocycles
Bruffaerts, Jeffrey,Von Wolff, Niklas,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
supporting information, p. 16486 - 16493 (2019/10/14)
Despite the hazardous nature of isocyanates, they remain key building blocks in bulk and fine chemical synthesis. By surrogating them with less potent and readily available formamide precursors, we herein demonstrate an alternative, mechanistic approach to selectively access a broad range of ureas, carbamates, and heterocycles via ruthenium-based pincer complex catalyzed acceptorless dehydrogenative coupling reactions. The design of these highly atom-efficient procedures was driven by the identification and characterization of the relevant organometallic complexes, uniquely exhibiting the trapping of an isocyanate intermediate. Density functional theory (DFT) calculations further contributed to shed light on the remarkably orchestrated chain of catalytic events, involving metal-ligand cooperation.
Synthesis and reactivity of N -alkyl carbamoylimidazoles: Development of N -methyl carbamoylimidazole as a methyl isocyanate equivalent
Duspara, Petar A.,Islam, Md. Sadequl,Lough, Alan J.,Batey, Robert A.
, p. 10362 - 10368 (2013/01/15)
A high-yielding synthesis of N-methyl carbamoylimidazole from 1,1-carbonyldiimidazole (CDI) and MeNH3Cl is described. The product is a crystalline, readily storable, water-stable compound that reacts as a methyl isocyanate (MIC) substitute. Reaction of N-methyl carbamoylimidazole in the presence of a base such as triethylamine occurs with nucleophiles such as amines, protected and unprotected amino acids, thiols and alcohols. The product N-methylureas, carbamates and thiocarbamates are obtained in good to excellent yields, with reactions occurring in either organic solvents or water. The protocol for the synthesis of N-methyl carbamoylimidazole is both scalable and general, occurring in quantitative yield at scales ranging from 300 mg to 20 g. The success of this method relies upon the reaction of CDI with the ammonium salt rather than the free amine, resulting in a significant improvement in the yield of N-methyl carbamoylimidazole. The reaction presumably involves a proton transfer from MeNH3Cl to the CDI, which results in the release of MeNH2 with simultaneous activation of the CDI as its protonated form. Other primary ammonium hydrochloride salts, including protected α-amino acid salts, give excellent yields of the corresponding N-alkyl carbamoylimidazoles and serve as alkyl isocyanate surrogates. The resultant N-alkyl carbamoylimidazoles can be converted to ureas in high yields without the formation of intermediary isocyanates.
Ring Cleavage Reaction of 1,3-Oxazine-2,4(3H)-dione Derivatives with Amines
Kinoshita, Toshio,Takeuchi, Kozue,Kondoh, Masaya,Furukawa, Sunao
, p. 2026 - 2029 (2007/10/02)
The reactions of 3,6-dimethyl -1,3-oxazine-2,4(3H)-diones (1a, 1b, and 1c) with various amines were investigated under various conditions.Several reactions products were obtained such as the pyrimidines (3a, 3b, 3c, and 3d), the acetoacetamides (4a, 4b, and 4c), (4-chlorophenyl)urethane (5a), and ethyl acetoacetate (4d) with primary amines, and the acetoacetamides (4e and 4f), the urethanes (5a and 5b), the carboxamides (5c, 5d, 5e, and 5f), and the butenamides (7a, 7b, and 7c) with secondary amines.In the case of 1c with amine, alcohol used as a solvent reacted as a nucleophile to give the urethane (5a or 5b).
