4363-89-7Relevant academic research and scientific papers
Oximes as reusable templates for the synthesis of ureas and carbamates by an: In situ generation of carbamoyl oximes
Senadi, Gopal Chandru,Mutra, Mohana Reddy,Lu, Ting-Yi,Wang, Jeh-Jeng
, p. 4272 - 4277 (2017/09/28)
Oximes have been identified as reusable templates for the synthesis of ureas and carbamates by an in situ generation of carbamoyl oximes under metal-free conditions. The recovered oxime has been utilised for three trials in the synthesis of urea derivatives without any loss in the yield and efficiency. In addition, this template approach could override the usage of hazardous and less stable isocyanates as substrates.
A high-yielding, expeditious, and multicomponent synthesis of urea and carbamate derivatives by using triphenylphosphine/trichloroisocyanuric acid system
Ghodsinia, Sara S.E.,Akhlaghinia, Batool
, p. 104 - 110 (2016/01/25)
An efficient method for the synthesis of urea and carbamate derivatives from amines and alcohols is described by using triphenylphosphine (PPh3)/trichloroisocyanuric acid system. The protocol allows for the preparation of symmetrical, unsymmetrical di, tri-, and tetra-substituted ureas and carbamates and is tolerant of a wide range of functional groups. To optimize the reaction conditions, experimental variables including temperature, the concentration of amine and alcohol, solvent, and reaction time were studied. Satisfactory yields were obtained at the optimized conditions. The present methodology is experimentally simple, mild, and represents a valuable alternative to the existing methods.
Mild and convenient synthesis of organic carbamates from amines and carbon dioxide using tetraethylammonium superoxide
Singh, Krishna Nand
, p. 2651 - 2654 (2008/02/12)
A safe and simple method of preparing organic carbamates has been achieved from amines and carbon dioxide using tetraethylammonium superoxide generated in situ. Copyright Taylor & Francis Group, LLC.
Synthesis of fluorine-18 labeled sulfonureas as β-cell imaging agents
Wiltshire,Prior,Dhesi,Maile
, p. 127 - 139 (2007/10/03)
Tolbutamide (1) and glyburide (7) are hypoglycemic drugs used to stimulate insulin secretion in type 2 diabetic patients. We have synthesized their fluorine-18 labeled analogs, 1-[(4-[18F]fluorobenzenesulfonyl)]-3-butyl]urea (p-[18F]fluorotolbutamide, 3a) and N-{4-[β-(2-[18F]fluoroethoxybenzene carboxamido)ethyl]benzenesulfonyl}-N′-cyclohexylurea (2-[18F]fluoroethoxyglyburide, 6a) as β-cell imaging agents. Compound 3a was synthesized via two approaches: One-step synthesis via nucleophilic substitution of p-nitrotolbutamide (2) with K[18F]/Kryptofix 2.2.2 in either CH3CN or DMSO gave a complicated mixture; a two-step synthesis via preparation and reaction of 4-[18F]fluorobenzenesulfonamide with butyl isocyanate in the presence of either copper (I) chloride or borontrifluoride etherate complex in CH3CN followed by HPLC purification yielded compound 3a in an overall yield of 1-2% with a synthesis time of 120 minutes from EOB. Compound 6a was synthesized by alkylation of the corresponding hydroxy precursor (5) with [18F]fluoroethyl tosylate in DMSO at 1200C for 20 minutes followed by HPLC purification in an overall yield of 5-10% with a synthesis time of 100 minutes from EOB. The lipid/water partition coefficient of compounds 3a and 6a was 3.13±0.28, n=6 and 124.33±21.61, n=8, respectively. The feasibility of using these radiotraces as β-cell imaging agents is under evaluation.
Pentadienylnitrobenzyl and Pentadienylnitropiperonyl Photochemically Removable Protecting Groups
Pirrung, Michael C.,Lee, Yong Rok,Park, Kaapjoo,Springer, James B.
, p. 5042 - 5047 (2007/10/03)
New photochemically removable protecting groups have been developed based on classical nitrobenzyl compounds modified by the inclusion of a pentadienyl group. It serves to trap through an internal Diels-Alder reaction the nitroso group produced as part of the photochemical deprotection process, preventing its further photochemistry or chemical reactions with nucleophiles.
