1196-72-1Relevant academic research and scientific papers
Direct conversion of carboxylic acids to various nitrogen-containing compounds in the one-pot exploiting curtius rearrangement
Kumar, Arun,Kumar, Naveen,Sharma, Ritika,Bhargava, Gaurav,Mahajan, Dinesh
, p. 11323 - 11334 (2019/09/10)
Herein we report, a single-pot multistep conversion of inactivated carboxylic acids to various N-containing compounds using a common synthetic methodology. The developed methodology rendered the use of carboxylic acids as a direct surrogate of primary amines, for the synthesis of primary ureas, secondary/tertiary ureas, O/S-carbamates, benzoyl ureas, amides, and N-formyls, exploiting the Curtius reaction. This approach has a potential to provide a diversified library of N-containing compounds, starting from a single carboxylic acid, based on the selection of the nucleophile.
A practically simple, catalyst free and scalable synthesis of: N -substituted ureas in water
Tiwari, Lata,Kumar, Varun,Kumar, Bhuvesh,Mahajan, Dinesh
, p. 21585 - 21595 (2018/06/26)
A practically simple, mild and efficient method is developed for the synthesis of N-substituted ureas by nucleophilic addition of amines to potassium isocyanate in water without organic co-solvent. Using this methodology, a variety of N-substituted ureas (mono-, di- and cyclic-) were synthesized in good to excellent yields with high chemical purity by applying simple filtration or routine extraction procedures avoiding silica gel purification. The developed methodology was also found to be suitable for gram scale synthesis of molecules having commercial application in large volumes. The identified reaction conditions were found to promote a unique substrate selectivity from a mixture of two amines.
Coordination compounds of Schiff base containing urea moiety
Kumar,Syamal, Arun,Gupta,Pandey,Ranid, Mukesh
, p. 745 - 752 (2012/11/07)
A MeOH solution of salicylaldehyde and o-hydroxyphenylurea in equimolar ratio reacts and forms the Schiff base, LH3 (1). The latter reacts with CuII, ZnII, CdII, MnII, CoII, NiII, FeIII, MoO2II, UO2II and Zr(OH)
NOVEL TRICYCLIC SPIRODERIVATIVES AS MODULATORS OF CHEMOKINE RECEPTOR ACTIVITY
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Page/Page column 37-38, (2008/06/13)
The invention provides compounds of formula (I) wherein m, R1, n, R2, q, p, X, Y, R3, R4, t and, R5 are as defined in the specification, processes for their preparation, pharmaceutical compositions containing them and their use in therapy.
Novel compounds
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, (2008/06/13)
The invention provides compounds of general formula (I) wherein Q, R, R2, R4, R5, R6, R7 and R8 are as defined in the specification, processes for their preparation, pharmaceutical compositions containing them and their use in therapy.
Intramolecular ureido and amide group participation in reactions of carbonate diesters
King, Stephen W.,Natarajan,Bembi, Ramesh,Fife, Thomas H.
, p. 10715 - 10721 (2007/10/02)
The cyclization of ethyl and phenyl 2-ureidophenylcarbonates in H2O at 30 °C involves two discrete steps with benzoxazolinone as the final product. The formation of benzoxazolinone is quantitative. Phenol is released in the initial step from both esters in an apparent OH--catalyzed reaction, which shows that intramolecular nucleophilic attack by the ureido group is via an anionic species. The pH-rate constant profile for the second step in the reaction of the ethyl ester is sigmoidal with pKapp = 8.9. The initial reaction involves a rearrangement, and the neighboring phenoxide ion of the intermediate participates in the second step. In view of the D2O solvent isotope effect (kH2O/kD2O = 1.2), this participation must be via a nucleophilic mechanism. The second step of the reaction of the phenyl ester, in which benzoxazolinone is formed, involves an apparent OH--catalyzed reaction of a cyclic intermediate. This intermediate was identified as N-carbamoylbenzoxazolinone, which thereby indicates that the initial nucleophilic attack is by nitrogen through a 5-membered-ring transition state. p-Nitrophenol release from p-nitrophenyl 2-ureidophenylcarbonate is only 18-fold faster than phenol release from the corresponding phenyl ester. Ratios of kOH(ortho) for phenol release from the 2-ureido-substituted esters to kOH(para) for OH--catalyzed hydrolysis of the corresponding 4-ureido-substituted esters are approximately 104 in all cases. In the intramolecular nucleophilic reactions of the ureido-substituted carbonate esters, a neutral species reaction is not observed, even at pH values as low as 3, in contrast with substituted benzoate esters having phenolic leaving groups. Also, in the apparent OH--catalyzed reactions of the carbonate diesters, only one cyclic product is obtained, whereas both oxygen and nitrogen attack occur in the nucleophilic reactions of carboxylate esters. The neighboring amide group of p-nitrophenyl o-(carboxamido)phenylcarbonate participates with nitrogen attack and apparent OH- catalysis. Intramolecular attack of nitrogen provides a rate enhancement of 103 in the release of p-nitrophenol over the OH--catalyzed hydrolysis of the para-substituted compound. Thus, in the intramolecular nucleophilic reactions of the carbonate diesters, nitrogen anion attack takes place preferentially when such attack is sterically favored (five-membered-ring transition state) and when there is an equal opportunity for oxygen or nitrogen attack.
o-Hydroxyphenylureas. Intermediates in the urea fusion synthesis of 2-benzoxazolinones
Nachman
, p. 1423 - 1425 (2007/10/02)
o-Hydroxyphenylureas have been identified as intermediates in the urea fusion synthesis of 2-benzoxazolinones. The pyrolysis of these intermediates represents a new alternate synthesis of the benzoxazolinone ring system.
