The short-lived positron-emitter carbon-11 (t1/2 = 20.4 min; β+, 99.8%) is prominent for labeling tracers for use in biomedical research with positron emission tomography (PET). Carbon-11 is produced for this purpose with a cyclotron, nowadays almost exclusively by the 14N(p,α)11C nuclear reaction, either on nitrogen containing a low concentration of oxygen (0.1–0.5%) or hydrogen (~5%) to produce [11C]carbon dioxide or [11C]methane, respectively. These primary radioactive products can be produced in high yields and with high molar activities. However, only [11C]carbon dioxide has some utility for directly labeling PET tracers. Primary products are required to be converted rapidly and efficiently into secondary labeling synthons to provide versatile radiochemistry for labeling diverse tracer chemotypes at molecular positions of choice. This review surveys known gas phase transformations of carbon-11 and summarizes the important roles that many of these transformations now play for producing a broad range of labeling synthons in carbon-11 chemistry.
[108549-23-1] C20H28NO2P (MW 345.42) InChI = 1S/C20H28NO2P/c1-17(2)21(18(3)4)24(22-15-19-11-7-5-8-12-19)23-16-20-13-9-6-10-14-20/h5-14,17-18H,15-16H2,1-4H3 InChIKey = ANPWLBTUUNFQIO-UHFFFAOYSA-N (phosphitylating reagent for alcohols; the resulting alkyl dibenzyl phosphite is transformed to the phosphoric monoesters by oxidation and subsequent debenzylation)2 Solubility: insoluble in cold H2O; soluble in CH2Cl2, THF, acetonitrile. Analysis of Reagent Purity: NMR: δP (CDCl3) +148.2. Preparative Methods: there are several synthetic methods,2-4 among which the reaction of benzyl alcohol with N,N-diisopropylphosphoramidous dichloride in the presence of tert-amine in diethyl ether, THF, or dioxane is convenient.5 Purification: chromatography on silica gel. Handling, Storage, and Precautions: can be stored in the absence of moisture and air for more than several months. A stock solution can be also prepared.
Abstract magnified image A variety of 2‐aryl quinazolines were synthesized from the condensation of 2‐aminobenzylamines and aryl aldehydes to form 2‐aryl‐1,2,3,4‐tetrahydroquinazolines and subsequent oxidation of the intermediates with MnO 2 . J. Heterocyclic Chem., (2010).
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Abstract A highly efficient method for specific synthesis of N ‐monomethylarylamines is presented. Anilines were treated with acetic anhydride and triethylamine in dry CH 2 Cl 2 to give the corresponding acetamides. The subsequent N ‐monomethylation of acetyl aryl amines with methyl iodide and NaH in THF introduced methyl group. Acid hydrolysis of the N ‐methyl acetanilides in ethylene glycol generated the corresponding N ‐methyl‐ N ‐aryl amines in high yields. This method was also used to synthesize ( E )‐2‐bromo‐5‐(4‐methylaminostyryl)pyridine that may be useful as an amyloid imaging agent for Alzheimer's disease.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
N-Methyl-d-aspartate (NMDA) receptor dysfunction has been linked to several neuropsychiatric disorders, including Alzheimer's disease, epilepsy, drug addiction, and schizophrenia. A radioligand that could be used with PET to image and quantify human brain NMDA receptors in the activated "open channel" state would be useful for research on such disorders and for the development of novel therapies. To date, no radioligands have shown well-validated efficacy for imaging NMDA receptors in human subjects. In order to discover improved radioligands for PET imaging, we explored structure–affinity relationships in N′-3-(trifluoromethyl)phenyl derivatives of N-aryl-N′-methylguanidines, seeking high affinity and moderate lipophilicity, plus necessary amenability for labeling with a positron-emitter, either carbon-11 or fluorine-18. Among a diverse set of 80 prepared N′-3-(trifluoromethyl)phenyl derivatives, four of these compounds (13, 19, 20, and 36) displayed desirable low nanomolar affinity for inhibition of [3H](+)-MK801 at the PCP binding site and are of interest for candidate PET radioligand development.
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