63-99-0Relevant academic research and scientific papers
Synthesis of Five-Membered Cyclic Guanidines via Cascade [3 + 2] Cycloaddition of α-Haloamides with Organo-cyanamides
Wang, Chuan-Chuan,Qu, Ya-Li,Liu, Xue-Hua,Ma, Zhi-Wei,Yang, Bo,Liu, Zhi-Jing,Chen, Xiao-Pei,Chen, Ya-Jing
, p. 3546 - 3554 (2021/02/16)
The convenient preparation of N2-unprotected five-membered cyclic guanidines was achieved through a cascade [3 + 2] cycloaddition between organo-cyanamides and α-haloamides under mild conditions in good to excellent yields (up to 99%). The corresponding cyclic guanidines could be easily transformed into hydantoins via hydrolysis.
Catalytic hydration of cyanamides with phosphinous acid-based ruthenium(ii) and osmium(ii) complexes: scope and mechanistic insights
álvarez, Daniel,Cadierno, Victorio,Crochet, Pascale,González-Fernández, Rebeca,López, Ramón,Menéndez, M. Isabel
, p. 4084 - 4098 (2020/07/09)
The synthesis of a large variety of ureas R1R2NC(O)NH2 (R1 and R2 = alkyl, aryl or H; 26 examples) was successfully accomplished by hydration of the corresponding cyanamides R1R2NCN using the phosphinous acid-based complexes [MCl2(η6-p-cymene)(PMe2OH)] (M = Ru (1), Os (2)) as catalysts. The reactions proceeded cleanly under mild conditions (40-70 °C), in the absence of any additive, employing low metal loadings (1 molpercent) and water as the sole solvent. In almost all the cases, the osmium complex 2 featured a superior reactivity in comparison to that of its ruthenium counterpart 1. In addition, for both catalysts, the reaction rates observed for the hydration of the cyanamide substrates were remarkably faster than those involving classical aliphatic and aromatic nitriles. Computational studies allowed us to rationalize all these trends. Thus, the calculations indicated that the presence of a nitrogen atom directly linked to the CN bond depopulates electronically the nitrile carbon by inductive effect when coordinated to the metal center, thus favouring the intramolecular nucleophilic attack of the OH group of the phosphinous acid ligand to this carbon. On the other hand, the higher reactivity of Os vs. Ru seems to be related with the lower ring strain on the incipient metallacycle that starts to form in the transition state associated with this key step in the catalytic cycle. Indirect experimental evidence of the generation of the metallacyclic intermediates was obtained by studying the reactivity of [RuCl2(η6-p-cymene)(PMe2OH)] (1) towards dimethylcyanamide in methanol and ethanol. The reactions afforded compounds [RuCl(η6-p-cymene)(PMe2OR)(NCNMe2)][SbF6] (R = Me (5a), Et (5b)), resulting from the alcoholysis of the metallacycle, which could be characterized by single-crystal X-ray diffraction. This journal is
Dual palladium-photoredox catalyzed chemoselective C-H arylation of phenylureas
Babu, Sakamuri Sarath,Shahid,Gopinath, Purushothaman
supporting information, p. 5985 - 5988 (2020/06/04)
A highly chemoselective C-H arylation of phenylureas has been accomplished using dual palladium-photoredox catalysis at room temperature without any additives, base or external oxidants. Regioselective C-H arylation ofN,N'-diaryl substituted unsymmetrical phenylureas has also been accomplished by a careful choice of aryl groups.
Transition Metal-Free Carbazole Synthesis from Arylureas and Cyclohexanones
Wu, Jun,Xie, Yanjun,Chen, Xiangui,Deng, Guo-Jun
supporting information, p. 3206 - 3211 (2016/10/21)
An efficient strategy for carbazole synthesis from arylureas and cyclohexanones under transition metal-free conditions has been developed. The combined use of potassium iodide and iodine could significantly improve the reaction efficiency to provide 2,6-disubstituted 9-arylcarbazoles in moderate to good yields. In this kind of transformation, the whole carbazole moiety (except the nitrogen atom) comes from two equivalents of cyclohexanones. (Figure presented.).
Synthesis and crystal structure of N-(3-benzylamino-2-cyano-3- methylthioacrylyl)-N′-(substituted phenyl)ureas
Zhong, Shi Hua,Fan, Ming Liang,Liu, Bing Yu,Wei, Dong Mei,Liu, Jian Bing
, p. 295 - 300 (2013/07/27)
Phenylurea groups were introduced into the frame of traditional cyanoacrylate and a series of N-(3-benzylamino-2-cyano-3-methylthioacrylyl)- N′-(substituted phenyl)ureas were synthesized. All compounds are new and their structures were confirmed by 1H NMR, 13C NMR and mass spectral analyses.
Ionic liquid mediated one-pot synthesis of 6-aminouracils
Chavan, Sunil S.,Degani, Mariam S.
supporting information; experimental part, p. 296 - 299 (2012/03/26)
A novel, one-pot synthesis of 6-aminouracils via in situ generated ureas and cyanoacetylureas in the presence of an ionic liquid catalyst, 1,1,3,3-tetramethylguanidine acetate, is described. The catalyst can be recycled for five consecutive runs without loss of activity. The mechanism for the ring closure of cyanoacetylurea to 6-aminouracil is also discussed.
Design, synthesis, and potential CNS activity of some new bioactive 1-(4-substituted-phenyl)-3-(4-oxo-2-methyl- 4H-quinazolin-3-yl)-urea
Kashaw, Sushil K.,Kashaw, Varsha,Mishra, Pradeep,Jain,Stables
experimental part, p. 738 - 745 (2012/05/20)
Twelve new 1-(4-substituted-phenyl)-3-(4-oxo- 2-methyl-4H-quinazolin-3-yl)- urea were synthesized and screened for anticonvulsant, CNS depressant, and sedativehypnotic activity. After i.p. injection to mice at doses of 30, 100, and 300 mg/kg body weight 2,3-Disubstitutedquinazolin- 4(3H)-one were examined in the maximal electroshock-induced seizures (MES) and subcutaneous pentylenetetrazole (scPTZ) induced seizure models in mice. Spectroscopic data and elemental analysis were consistent with the newly synthesized compounds. The neurotoxicity was assessed using the rotorod method. M3, M4 and M10 were found to be active in both MES screen and scPTZ screen at 0.5 h. All except M11 showed more than 44% decrease in locomotor activity after 1 h of compound administration via actophotometer screen. CNS-depressant activity screened with the help of the forced swim method resulted into some potent compounds. Except for M6 and M11 other tested compounds were found to exhibit potent CNS depressants activity as indicated by increased immobility time. It can be concluded that newly synthesized compounds possessed sedative-hypnotic and CNS depressant activities. Springer Science+Business Media, LLC 2010.
Synthesis, anticonvulsant and CNS depressant activity of some new bioactive 1-(4-substituted-phenyl)-3-(4-oxo-2-phenyl/ethyl-4H-quinazolin-3-yl)-urea
Kashaw, Sushil K.,Kashaw, Varsha,Mishra, Pradeep,Jain,Stables
experimental part, p. 4335 - 4343 (2009/12/24)
Several new 1-(4-substituted-phenyl)-3-(4-oxo-2-phenyl/ethyl-4H-quinazolin-3-yl)-urea were synthesized and screened for anticonvulsant, CNS depressant and sedative-hypnotic activity in the mice. After i.p. injection to mice at doses of 30, 100, and 300 mg/kg body weight synthesized compounds were examined in the maximal electroshock induced seizures (MES) and subcutaneous pentylenetetrazole (scPTZ) induced seizure models in mice. Spectroscopic data and elemental analysis were consistent with the newly synthesized compounds. The neurotoxicity was assessed using the rotorod method. Compounds E1, E6, E9, E12, P3, P4 and P6 were found to be active in the MES screen whereas E1, P4, P6 and P11 were found to be active in the scPTZ screen. All except E6, E11 and P6 showed more than 50% decrease in locomotor activity at 1 h of compound administration via actophotometer screen. CNS depressant activity screened with the help of the forced swim method resulted into some potent compounds. All the compounds were found to exhibit potent CNS depressants activity as indicated by increased immobility time. It can be concluded that newly synthesized compounds possessed promising CNS activities.
A kinetic study of the denitrosation and hydrolysis reactions of N-nitrosophenylureas
Casado, Julio,Castro, Albino,Lorenzo, Francisco Manuel,Meijide, Francisco,Mosquera, Manuel
, p. 597 - 601 (2007/10/02)
The kinetics of the decomposition of N-nitroso-phenylurea in aqueous solution have been studied in the acidity range 0.035-0.36 mol.l-1-HCIO4 and in buffer solutions of pH 3.98-6.14.Below pH 3 the decomposition proceeds mainly by acid catalysed denitrosation, but a small uncatalysed contribution has also been detected.The general acid catalysis, the absence of nucleophilic catalysis by halides and the isotopic effect (kH:kD ca. 1.5) allow a mechanism to be proposed in which the protonation of N-nitrosophenylurea is the rate determining step.The results obtained on studying the denitrosation of some ring-derivatives of N-nitrosophenylurea show a little effect on reaction rate.The mechanism proposed for the hydrolysis reaction (studied at pH > 3.9) involves the formation of a nitrosourea hydrate under steady state conditions, which undergoes an OH(1-) catalysed reaction yielding benzenediazonium ion and an uncatalysed reaction yielding an unidentified product.This latter pathway is virtually negligible at the highest values of pH worked with.
