- Methoxycarbonylation of Alkyl-, Cycloalkyl-, and Arylamines with Dimethyl Carbonate in the Presence of Binder-Free Zeolite
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Abstract: Methyl N-alkyl-, N-cycloalkyl-, and N-arylcarbamates were synthesized by reaction of the correspondingamines with dimethyl carbonate in the presence of binder-free FeHY zeolite. Theoptimal conditions (reactant ratio, amount of the catalyst, temperature,reaction time) were found to afford the target products with high yields.
- Khazipova, A. N.,Khusnutdinov, R. I.,Mayakova, Yu. Yu.,Shchadneva, N. A.
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p. 1228 - 1235
(2020/10/02)
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- Reversible C-C bond activation enables stereocontrol in Rh-catalyzed carbonylative cycloadditions of aminocyclopropanes
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Upon exposure to neutral or cationic Rh(I)-catalyst systems, amino-substituted cyclopropanes undergo carbonylative cycloaddition with tethered alkenes to provide stereochemically complex N-heterocyclic scaffolds. These processes rely upon the generation and trapping of rhodacyclopentanone intermediates, which arise by regioselective, Cbz-directed insertion of Rh and CO into one of the two proximal aminocyclopropane C-C bonds. For cyclizations using cationic Rh(I)-systems, synthetic and mechanistic studies indicate that rhodacyclopentanone formation is reversible and that the alkene insertion step determines product diastereoselectivity. This regime facilitates high levels of stereocontrol with respect to substituents on the alkene tether. The option of generating rhodacyclopentanones dynamically provides a new facet to a growing area of catalysis and may find use as a (stereo)control strategy in other processes.
- Shaw, Megan H.,McCreanor, Niall G.,Whittingham, William G.,Bower, John F.
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supporting information
p. 463 - 468
(2015/01/30)
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- Preparation of Methyl Carbamates from Primary Alkyl- and Arylcarboxamides Using Hypervalent Iodine
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A series of 14 primary alkyl- and arylcarboxamides were treated with PhI(OAc)2 in KOH-CH3OH at 5-10 deg C to give the corresponding methyl carbamates in good to excellent yields.These conditions avoid the use of elemental bromine or heavy metal reagents (Pb(OAc)4, AgOAc, Hg(OAc)2), while taking advantage of the commercial availability of PhI(OAc)2.The methyl carbamates are easily purified via column chromatography on silica gel.The isolated yields of the carbamates ranged from 72percent for methyl N-cyclopropylcarbamate to 97percent for methyl N-phenylcarbamate.
- Moriarty, Robert M.,Chany, Calvin J.,Vaid, Rahde K.,Prakash, Om,Tuladhar, Sudersan M.
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p. 2478 - 2482
(2007/10/02)
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- New Compounds with Possible Pharmacological Activity
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Sixty-two new organic compounds are reported.These were prepared for testing in a variety of pharmacological screens or as chemical intermediates.None was found to be more active or less toxic than known medicinals.
- Moffett, Robert Bruce
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p. 176 - 183
(2007/10/02)
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