- Electrochemical Synthesis of Carbodiimides via Metal/Oxidant-Free Oxidative Cross-Coupling of Amines and Isocyanides
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This work discloses an electrochemical oxidative cross-coupling of amines with aryl and aliphatic isocyanides. In an undivided cell, the reaction proceeds without involving any transition-metal catalyst, oxidant, or toxic reagents providing carbodiimides in good yields, thereby circumventing stoichiometric chemical oxidants, with H2 as the only byproduct. Moreover, carbodiimides were in situ converted into unsymmetrical ureas in moderate to good yields using an electricity ON-OFF strategy.
- Badsara, Satpal Singh,Jaiswal, Pradeep K.,Malviya, Bhanwar Kumar,Sharma, Siddharth,Verma, Ved Prakash
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supporting information
(2020/03/19)
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- Ultrasonic-assisted synthesis of carbodiimides from N,N′-disubstituted thioureas and ureas
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A facile and efficient sonochemical method for the preparation of carbodiimides from their corresponding thioureas or ureas was described. Using Ph3P–I2 combination in the presence of triethylamine, various diaryl, aryl–alkyl, as well as dialkyl substituted substrates could be converted into carbodiimides in good-to-excellent yields within short reaction times under mild conditions with simple experimental setup. Graphical abstract: [Figure not available: see fulltext.]
- Duangkamol, Chuthamat,Pattarawarapan, Mookda,Phakhodee, Wong
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p. 1945 - 1949
(2016/10/21)
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- Ultrasound-assisted synthesis of substituted guanidines from thioureas
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Ultrasound-assisted synthesis of guanidine derivatives was developed using 2,4,6-trichloro-1,3,5-triazine as an inexpensive dehydrosulfurization reagent. Both 1,3-alkylaryl- and 1,3-diaryl-thioureas were rapidly converted into carbodiimides before subsequent reaction with aromatic or aliphatic amines. The method allows rapid access to highly substituted guanidines in good to excellent yields under mild conditions and with minimal use of solvent.
- Pattarawarapan, Mookda,Jaita, Subin,Wangngae, Sirilak,Phakhodee, Wong
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supporting information
p. 1354 - 1358
(2018/03/29)
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- Carbodiimide metathesis catalyzed by vanadium oxo and imido complexes via imido transfer
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Vanadium oxo and imido complexes: V(NC6H4Me)(OtBu)3 (1), V(NC6H4Me)Cl3 (2), V(O)(OtBu)3 (3), V(O)(OtPr)3 (4), V(O)(acac)2 (
- Birdwhistell,Lanza,Pasos
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p. 200 - 205
(2007/10/03)
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- On the Reaction of Isocyanides with Nitrile Imines
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Four competing reactions have been found to occur when nitrile imines 2 are generated from 1 in the presence of isocyanides 3.The products obtained include i) 1,2,3-triazolium salts 6, ii) 1,2,4-triazolium salts 8, iii) dihydrotriazolyl-substituted pyrazolamines 11, and iv) unstable 1,2-diazetimine derivatives 12 which in turn give carbodiimides 13, nitriles 14, quinoxalinamines 15, and possibly 1,2,4-triazoles 16 (after addition of 2).The proportions, in particular those of 6,8, and 11, depend on the reaction conditions; thus, triethylamine used in excess can oppress the formation of 6 in favour of 8 and 11. - The structure of 11 has been elucidated by means of X-ray diffraction analyses of 11a and c. - Key Words: Isocyanides / Nitrile imines / Triazolium salts / Pyrazoles / 1,2-Diazet-3-imines
- Moderhack, Dietrich,Lorke, Michael,Ernst, Ludger,Schomburg, Dietmar
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p. 1633 - 1640
(2007/10/02)
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- Aminoethynyl Metallations, 13. - Synthesis and Reactions of 3-Aminopropiolamidines
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The lithium aminoacetylides 1 react with the carbodiimides 2 to give the lithium propiolamidinates 3, which are hydrolyzed to yield the 3-aminopropiolamidines 4. 3 can directly be converted into the persubstituted ynamine carboxamidines 5 by adding methyl iodide.The amidines 4 with less activated C/C-triple bonds (NR1R2 = N(Me)Ph or NPh2) react with thioformaldehyde dioxide or with diphenyl ketene exclusively at the NH group with formation of the sulfonamides 6 or of an carboxamide 7.The more reactive (diethylaminoacetylene)carboxamidine 4h adds a second molecule of ketene to furnish the cyclobutenone derivative 8.The propiolamidine 4b with a diphenylamino group at the triple bond reacts with concentrated hydrochloric acid under formation of the amidinium salt 9 and partly by addition of a second molecule of hydrochloride to the triple bond to give 10.Adding tosyl azide to 4 we obtained via the triazole 11 by two successive 1,5-cyclizations the amidino-1,2,3-triazoles 12.The 3-aminopropiolamidines 4 bearing at least one aryl group in the amidine moiety cyclize to give the 2,4-diaminoquinolines 17 if they are chromatographed on silica gel.The same or analogously substituted quinolines 17 are obtained by the reaction of the simple ynamines 15 (H, Me, or Ph in the β-position) with the corresponding carbodiimides 2. 2-Anilino-4-diethylamino-3-methylquinoline (17e) is hydrolyzed in acidic solution to give the 4-quinolone derivative 19.
- Himbert, Gerhard,Schwickerath, Willi
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