13738-74-4Relevant academic research and scientific papers
Lewis base-catalyzed reaction of aziridinofullerene with ureas for the preparation of fulleroimidazolidinones
Xing, Meng-Lei,Lu, Xin-Wei,Miao, Chun-Bao,Li, Jia-Xing,Sun, Xiao-Qiang,Yang, Hai-Tao
, p. 11774 - 11779 (2015/01/09)
The Lewis base-catalyzed double nucleophilic substitution reaction of N-tosylaziridinofullerene with various ureas allows the easy preparation of fulleroimidazolidinones with a high tolerance for functional groups. Alkyl-substituted ureas show better reactivity than aryl-substituted ureas.
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.
Lewis Acid Catalysed Preparation of some Carbamates and Sulphonylureas. Application to the Determination of Enantiomeric Purity of Chiral Alcohols
Irie, Hiroshi,Nishimura, Masataka,Yoshida, Morihiro,Ibuka, Toshiro
, p. 1209 - 1210 (2007/10/02)
Lewis acids such as boron trifluoride-diethyl ether and aluminium chloride catalyze the reaction of alcohols and sulphonamides with isocyanates, affording carbamates and sulphonylureas, respectively, in acceptable yield.Applied to the formation of diastereoisomeric carbamates from chiral alcohols using Pirkle's reagents, , this technique provides a convenient method for determination of enantiomeric purity.
