- Hydroamination and Hydrophosphination of Isocyanates/Isothiocyanates under Catalyst-Free Conditions
-
Symmetrical and unsymmetrical N,N’-disubstituted as well as trisubstituted ureas/thioureas by the hydroamination of isocyanates/isothiocyanates, and various phosphathioureas by the hydrophosphination of isothiocyanates have been synthesized in good to excellent yields under catalyst-free and mild conditions. This protocol is also applicable for the efficient synthesis of chiral ureas and thioureas and common herbicides, such as fenuron and monuron.
- Zhu, Xiancui,Xu, Mengchen,Sun, Jinrong,Guo, Dianjun,Zhang, Yiwei,Zhou, Shuangliu,Wang, Shaowu
-
p. 5213 - 5218
(2021/10/19)
-
- Catalyst-free synthesis of substituted pyridin-2-yl, quinolin-2-yl, and isoquinolin-1-yl carbamates from the corresponding hetaryl ureas and alcohols
-
A novel catalyst-free synthesis ofN-pyridin-2-yl,N-quinolin-2-yl, andN-isoquinolin-1-yl carbamates utilizes easily accessibleN-hetaryl ureas and alcohols. The proposed environmentally friendly technique is suitable for the good-to-high yielding synthesis of a wide range ofN-pyridin-2-yl orN-quinolin-2-yl substituted carbamates featuring electron-donating and electron-withdrawing groups in the azine rings and containing various primary, secondary, and even tertiary alkyl substituents at the oxygen atom (48-94%; 31 examples). The DFT calculation and experimental study showed that the reaction proceeds through the intermediate formation of hetaryl isocyanates. The method can be applied to obtainN-isoquinolin-1-yl carbamates, although in lower yields, and ethyl benzo[h]quinolin-2-yl carbamate has also been successfully synthesized (68%).
- Baykov, Sergey V.,Boyarskaya, Irina A.,Boyarskiy, Vadim P.,Geyl, Kirill K.,Kasatkina, Svetlana O.
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p. 6059 - 6065
(2021/07/21)
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- Lanthanum(III) Trifluoromethanesulfonate Catalyzed Direct Synthesis of Ureas from N-Benzyloxycarbonyl-, N -Allyloxycarbonyl-, and N -2,2,2-Trichloroethoxycarbonyl-Protected Amines
-
A novel lanthanum triflate mediated conversion of N -benzyloxycarbonyl-, N -allyloxycarbonyl-, and N -trichloroethoxycarbonyl-protected amines into nonsymmetric ureas was discovered. In this study, lanthanum triflate was found to be an effective catalyst for preparing various nonsymmetric ureas from protected amines. A variety of protected aromatic and aliphatic carbamates reacted readily with various amines in the presence of lanthanum triflate to generate the desired ureas in high yields. This result demonstrated that this novel lanthanum triflate catalyzed preparation of ureas from Cbz, Alloc, and Troc carbamates can be employed for the formation of various urea structures.
- Bui, Tien Tan,Kim, Hee-Kwon
-
supporting information
p. 997 - 1002
(2020/06/17)
-
- Biochemical and microbiological evaluation of: N-aryl urea derivatives against mycobacteria and mycobacterial hydrolases
-
A focused library of 24 N-aryl urea derivatives was prepared and evaluated against serine esterases of Mycobacterium tuberculosis (Mtb) Rv3802c and Mtb Ag85C. The members of the library were evaluated for both selectivity and mode of inhibition. Furan-bas
- Vartak, Abhishek,Goins, Christopher,De Moura, Vinicius Calado Nogueira,Schreidah, Celine M.,Landgraf, Alexander D.,Lin, Boren,Du, Jianyang,Jackson, Mary,Ronning, Donald R.,Sucheck, Steven J.
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p. 1197 - 1204
(2019/07/25)
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- CaI2-Catalyzed direct transformation of: N -Alloc-, N -Troc-, and N -Cbz-protected amines to asymmetrical ureas
-
A novel and facile CaI2-catalyzed direct synthesis of asymmetrical ureas from N-Alloc-, N-Troc-, and N-Cbz-protected amines is developed. In this study, the efficient reaction of Alloc-, Troc-, and Cbz-carbamates with amines in the presence of catalytic CaI2 successfully generated various asymmetrical ureas. This catalytic synthetic procedure provided the desired ureas via reactions of these protected aromatic and aliphatic amines with various amines in high yields without side products. This suggests that novel direct synthesis of ureas from Alloc-, Troc-, and Cbz-carbamates can be a promising approach for the synthesis of useful ureas.
- Tran, Van Hieu,Kim, Hee-Kwon
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p. 14093 - 14101
(2019/09/18)
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- Chemoselective isocyanide insertion into the N-H bond using iodine-DMSO: Metal-free access to substituted ureas
-
Insertion of isocyanides into the N-H bond gives access to many medicinally important and structurally diverse complex nitrogen-containing heterocycles. Although the transition metal catalyzed isocyanide insertion into the N-H bond is very common, polymerization of isocyanides in the presence of a transition metal and their strong coordination with metals are the common drawbacks. On the other hand, the inertness of most of the isocyanides towards amines in the absence of a metal catalyst has stymied the growth of the metal-free approach for isocyanide insertion into amines. As a result, only a handful of metal catalysed methods with limited substrate scopes have been reported for the synthesis of ureas via isocyanide insertion into amines and no metal-free version has been reported yet. Interestingly, chemoselective isocyanide insertion into amines has not been reported in the literature. We employed the I2-DMSO reagent system for the chemoselective synthesis of ureas, where isocyanides react with aliphatic amines only, while aromatic amines need a nucleophilic activator (DABCO) to facilitate the formation of ureas. This method gave direct and chemoselective access to ureas by evading the commonly used yet toxic isocyanates.
- Bora, Porag,Bez, Ghanashyam
-
supporting information
p. 8363 - 8366
(2018/08/03)
-
- Facile direct synthesis of unsymmetrical ureas from N-Alloc-, N-Cbz-, and N-Boc-protected amines using DABAL-Me3
-
A practical synthetic method for the direct synthesis of unsymmetrically substituted ureas from N-Alloc-, N-Cbz-, and N-Boc-protected amines is described. In this study, efficient direct conversion of the Alloc-, Cbz-, and Boc-carbamate compounds to ureas was achieved in the presence of DABAL-Me3, an air stable and easily handled reagent. Using this reaction method, both protected aromatic and aliphatic amines were successfully transformed into various trisubstituted and tetrasubstituted ureas with high yields without side product. Our findings offer promising guidelines for direct preparation of useful ureas from N-Alloc-, N-Cbz-, and N-Boc-carbamates.
- Kang, Soosung,Kim, Hee-Kwon
-
p. 4036 - 4046
(2018/06/13)
-
- Synthesis of 11C-labelled ureas by palladium(II)-mediated oxidative carbonylation
-
Positron emission tomography is an imaging technique with applications in clinical settings as well as in basic research for the study of biological processes. A PET tracer, a biologically active molecule where a positron-emitting radioisotope such as carbon-11 has been incorporated, is used for the studies. Development of robust methods for incorporation of the radioisotope is therefore of the utmost importance. The urea functional group is present in many biologically active compounds and is thus an attractive target for incorporation of carbon-11 in the form of [11C]carbon monoxide. Starting with amines and [11C]carbon monoxide, both symmetrical and unsymmetrical 11C-labelled ureas were synthesised via a palladium(II)-mediated oxidative carbonylation and obtained in decay-corrected radiochemical yields up to 65%. The added advantage of using [11C]carbon monoxide was shown by the molar activity obtained for an inhibitor of soluble epoxide hydrolase (247 GBq/μmol-319 GBq/μ mol). DFT calculations were found to support a reaction mechanism proceeding through an 11C-labelled isocyanate intermediate.
- Roslin, Sara,Brandt, Peter,Nordeman, Patrik,Larhed, Mats,Odell, Luke R.,Erikssoni, Jonas
-
-
- Synthesis of ureas in the bio-alternative solvent Cyrene
-
Cyrene as a bio-alternative solvent: a highly efficient, waste minimizing protocol for the synthesis of ureas from isocyanates and secondary amines in the bio-available solvent Cyrene is reported. This method eliminated the use of toxic solvents, such as
- Mistry, Liam,Mapesa, Kopano,Bousfield, Thomas W.,Camp, Jason E.
-
supporting information
p. 2123 - 2128
(2017/07/24)
-
- Preparation method for alkyl/benzyl/aryl urea compounds through heterogeneous-phase catalysis
-
The invention discloses a preparation method for formula (I) compounds, and the compounds are obtained by reacting a formula (II) compound with a formula (III) compound in a solvent in carbon monoxide atmosphere under catalysis of a heterogeneous-phase pa
- -
-
Paragraph 0063-0071; 0072; 0073; 0074; 0076; 0078; 0082
(2016/10/09)
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- Pd/C Catalyzed Carbonylation of Azides in the Presence of Amines
-
A facile and efficient Pd/C-catalyzed carbonylation of both aliphatic and aromatic azides in the presence of amines is reported. Serving as the widely existed fragments in an array of biological pharmaceuticals, functionalized unsymmetrical ureas were str
- Zhao, Jin,Li, Zongyang,Yan, Shuaihu,Xu, Shiyang,Wang, Ming-An,Fu, Bin,Zhang, Zhenhua
-
p. 1736 - 1739
(2016/05/19)
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- A synthetic approach to N -aryl carbamates via copper-catalyzed Chan-Lam coupling at room temperature
-
A mild and efficient synthesis of N-arylcarbamates was achieved by reacting azidoformates with boronic acids in the presence of 10 mol % of copper chloride catalyst. The reaction proceeds readily in an open flask at room temperature without additional base, ligand, or additive. Rapid access to urea analogues via a two-step one-pot procedure is enabled by reacting N-arylcarbamates with aluminum-amine complexes. In addition, among several boronic acid derivatives prepared, dimethylphenyl boronate was found to react rapidly in its reaction with benzyl azidoformate, invoking in situ generation of this species in the catalytic cycle.
- Moon, Soo-Yeon,Kim, U. Bin,Sung, Dan-Bi,Kim, Won-Suk
-
p. 1856 - 1865
(2015/02/19)
-
- Palladium-mediated oxidative carbonylation reactions for the synthesis of 11C-radiolabelled ureas
-
Palladium(II)-mediated oxidative carbonylation reactions have been used to synthesize 11C-radiolabelled ureas via the coupling of amines with [11C]carbon monoxide, in a one-pot process. Following trapping of 11CO in a solution of copper(I) tris(3,5-dimethylpyrazolyl)borate, homocoupling reactions of primary aliphatic amines proceed in the presence of Pd(PPh3)2Cl2 to give the corresponding N,N-disubstituted [11C]ureas. Secondary amines do not produce the corresponding N,N,N,N-tetrasubsituted [11C]ureas under these conditions. This difference in reactivity allows for the formation of unsymmetrical N,N',N'-trisubstituted [11C]ureas using a mixture of a primary amine and a reactive secondary amine. The potential use of this method in positron emission tomography (PET) was demonstrated by the synthesis of the M1 muscarinic acetylcholine receptor radiotracer, [11C-carbonyl] GSK1034702.
- Kealey, Steven,Husbands, Stephen M.,Bennacef, Idriss,Gee, Antony D.,Passchier, Jan
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p. 202 - 208
(2014/05/06)
-
- Ethyl 2-cyano-2-(4-nitrophenylsulfonyloxyimino)acetate-mediated lossen rearrangement: Single-pot racemization-free synthesis of hydroxamic acids and ureas from carboxylic acids
-
Ethyl 2-cyano-2-(4-nitrophenylsulfonyloxyimino)acetate (4-NBsOXY) mediated Lossen rearrangement and its application for the synthesis of ureas is demonstrated. Required hydroxamic acids for the Lossen rearrangements were synthesized from carboxylic acids using the same reagent. Finally, reaction of an amine with the produced isocyanate resulted in urea. Good yields without racemization were achieved under milder and simpler reaction conditions. Reactions are compatible with common N-protecting groups, such as Boc, Fmoc, Cbz, and benzyl, as well as various OH protecting groups, such as tBu and Bzl. Conversion from carboxylic acid to urea is achieved in one pot. Most importantly, byproducts Oxyma [ethyl 2-cyano-2-(hydroxyimino)acetate] and 4-nitrobenzenesulfonic acid can be recovered easily and can be recycled to prepare the reagent. Thus, the method is environmentally friendly and cost-effective.
- Thalluri, Kishore,Manne, Srinivasa Rao,Dev, Dharm,Mandal, Bhubaneswar
-
p. 3765 - 3775
(2014/05/20)
-
- Highly efficient synthesis of ureas and carbamates from amides by iodosylbenzene-induced hofmann rearrangement
-
A simple and efficient method for the synthesis of 1,3-disubstituted ureas and carbamates from amides by using iodosylbenzene as the oxidant is described. Symmetric and asymmetric ureas and carbamates can be prepared by this procedure in up to 98 % yield. Ureidopeptides can also be prepared in good yield by this method. A simple and efficient method for the synthesis of 1,3-disubstituted ureas and carbamates from amides by using iodosylbenzene as the oxidant is described. By using this method, heterocyclic products can be easily obtained in excellent yield. Ureidopeptides can also be prepared in good yield by this procedure. Copyright
- Liu, Peng,Wang, Zhiming,Hu, Xianming
-
experimental part
p. 1994 - 2000
(2012/05/05)
-
- Synthesis of substituted [11C]ureas and [11C] sulphonylureas by Rh(I)-mediated carbonylation
-
The urea moiety is present in many biologically active compounds and thus an attractive target for 11C-labelling. To extend the scope of the rhodium(I)-mediated carbonylative cross-coupling reaction between an azide and an amine and investigate
- Aberg, Ola,Langstroem
-
experimental part
p. 38 - 42
(2011/09/21)
-
- Acetoacetanilides as masked isocyanates: Facile and efficient synthesis of unsymmetrically substituted ureas
-
Figure Presented. A general and practical method for the preparation of unsymmetrically substituted ureas has been developed. By the reactions of acetoacetanilides with various amines including primary/secondary amines, a series of substituted aryl ureas were achieved in high yields. Acetoacetanilide substrates can be considered as masked reagents that liberate reactive isocyanates in situ.
- Wei, Ying,Liu, Jing,Lin, Shaoxia,Ding, Hongqian,Liang, Fushun,Zhao, Baozhong
-
supporting information; experimental part
p. 4220 - 4223
(2010/11/04)
-
- Accelerating effects of N-aryl-N′,N′-dialkyl ureas on epoxy-dicyandiamide curing system
-
This report focuses on epoxy-dicyandiamide (DICY) curing system accelerated by N-aryl-N′,N′-dialkyl urea, aiming at clarifying the accelerating mechanism and the relationship between accelerating effect and molecular structure of the accelerators. Nine N-aryl-N′,N′-dialkyl ureas were synthesized and investigated with measurements of differential scanning calorimetry, thermo gravimetric/differential thermal analysis and NMR spectroscopy. The results revealed that the ureas released the corresponding secondary amines by the thermal dissociation in the presence of epoxide, which led to the formation of tertiary amines that catalyze the addition reaction of DICY to epoxide. Moreover, a tendency that the ureas able to release more compact amines exhibited higher acceleration effects was discovered.
- Liu, Xiang Dong,Kimura, Mika,Sudo, Atsushi,Endo, Takeshi
-
experimental part
p. 5298 - 5305
(2011/06/21)
-
- Phenyl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylate as carbonyl source: Facile and selective synthesis of carbamates and ureas under mild conditions
-
The selective syntheses of carbamates, symmetric -ureas, and unsymmetrical ureas have been accomplished by the -reaction of amines with phenyl 4,5-dichloro-6-oxopyridazine-1(6H)-carboxylate as a carbonyl source under mild conditions. It is noteworthy that this process is mild, economic, and convenient.
- Lee, Hyung-Geun,Kim, Min-Jung,Park, Song-Eun,Kim, Jeum-Jong,Kim, Bo Ram,Lee, Sang-Gyeong,Yoon, Yong-Jin
-
experimental part
p. 2809 - 2814
(2010/03/03)
-
- Synthesis of unsymmetrical ureas by sulfur-assisted carbonylation with carbon monoxide and oxidation with molecular oxygen under mild conditions
-
With ambient pressure of carbon monoxide and oxygen at room temperature, N,N-dialkyl-N′-arylureas were selectively accessible from secondary amines, aromatic amines, and sulfur in good to excellent yields. For example, N-butyl-N-methyl-N′-(3,4-dichlorophenyl)urea, which is used as a herbicide (neburon), was afforded successfully from butylmethylamine (2 equiv), 3,4-dichloroaniline (1 equiv) and sulfur (1 equiv) in 79% (21.8 g) yield using carbon monoxide (0.1 MPa) and oxygen (0.1 MPa) at 20°C in DMF. Georg Thieme Verlag Stuttgart.
- Mizuno, Takumi,Nakai, Takeo,Mihara, Masatoshi
-
experimental part
p. 2492 - 2496
(2009/12/08)
-
- N-carbonylation of lithium azaenolates of amides, formamides, ureas, and carbamates with carbon monoxide mediated by selenium
-
N-Carbonylation of less nucleophilic nitrogen compounds was achieved by the reaction of the lithium azaenolates with carbon monoxide and selenium. This reaction proceeds in the cases of amides, formamides, ureas, and carbamates, leading to the formation of the corresponding carbamosele-noates in good to high yields after trapping with BuI.
- Fujiwara, Shin-Ichi,Okada, Kazuhiro,Shikano, Yasukazu,Shimizu, Yoshihiko,Tsutomu, Shin-Ike,Terao, Jun,Kambe, Nobuaki,Sonoda, Noboru
-
p. 273 - 276
(2007/10/03)
-
- Synthesis of carbamates and ureas using Zr(IV)-catalyzed exchange processes
-
Equation presented Zirconium(IV)-catalyzed exchange processes have been developed to prepare both carbamates and ureas from dialkyl arbonates and carbamates employing 2-hydroxypyridine (HYP) and 4-methyl-2-hydroxyquinoline (MeHYQ) as catalytic additives, respectively A microwave acceleration effect was observed in Zr(IV)-catalyzed carbamate-urea exchange.
- Han, Chong,Porco Jr., John A.
-
p. 1517 - 1520
(2008/02/02)
-
- A new practical method for the synthesis of unsymmetrical ureas via high-pressure-promoted condensation of 2,2,2-trichloroethyl carbamates (Troc-carbamates) with amines
-
A new practical method for the synthesis of unsymmetrical ureas was achieved by condensation between 2,2,2-trichloroethyl carbamates (Troc-carbamates) and primary or secondary amines under high-pressure conditions.
- Azad, Saleha,Kumamoto, Koji,Uegaki, Kaoru,Ichikawa, Yoshiyasu,Kotsuki, Hiyoshizo
-
p. 587 - 590
(2007/10/03)
-
- Pd(OAc)2-catalyzed carbonylation of amines
-
A phosphine-free catalytic system [Pd(OAc)2-Cu(OAc) 2-air] induced a substrate-specific carbonylation of amines in boiling toluene under CO gas (1 atm). Symmetrical N,N′-dialkylureas were obtained by the carbonylation of primary amines. N,N,N′-Trialkylureas were selectively formed by addition of a secondary amine to the above reaction vessel. Secondary amines did not give tetraalkylureas. However, dialkylamines with a phenyl group on their alkyl chains, such as N-monoalkylated benzylic amine or phenethylamine derivatives, underwent a direct aromatic carbonylation to afford five- or six-membered benzolactams. In the carbonylation, the chelation effect or steric repulsion between Pd(II) and the meta-substituent in the ortho-palladation and the ring sizes of cyclopalladation products that were formed prior to carbonylation were found to generate good site selectivity and increase the reaction rate. In contrast, carbonylation of ω- arylalkylamines with a hydroxyl group gave neither ureas nor benzolactams but instead produced 1,3-oxazolidinones smoothly. Hydrochlorides of amines also underwent carbonylation to afford the corresponding amides under the conditions used. This procedure made it possible to prepare ureas of amino acid esters and N-alkylcarbamates in practical yields.
- Orito, Kazuhiko,Miyazawa, Mamoru,Nakamura, Takatoshi,Horibata, Akiyoshi,Ushito, Harumi,Nagasaki, Hideo,Yuguchi, Motoki,Yamashita, Satoshi,Yamazaki, Tetsuro,Tokuda, Masao
-
p. 5951 - 5958
(2007/10/03)
-
- The direct conversion of carbamates to ureas using aluminum amides
-
The conversion of carbamates into ureas using aluminum amide complexes is reported. This reaction is a convenient method to prepare bi-, tri- and tetra-substituted ureas from carbamate-protected primary or secondary amines by reaction with primary or secondary amines in the presence of stoichometric quantities of trimethylaluminum. A reactivity trend of the various carbamates was observed and methyl and benzyl carbamates were reacted selectively in the presence of t-butyl carbamates.
- Lee, Sang-Hyuep,Matsushita, Hana,Clapham, Bruce,Janda, Kim D.
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p. 3439 - 3443
(2007/10/03)
-
- Sequential base-promoted annulation/palladium-catalyzed domino 1,5-enyne arylation and vinylation of α-propargylaminohydrazones
-
Stereoselective dominos: Cascade reactions of easily accessible α-propargylaminohydrazones 1 represent a simple and efficient method for the preparation of pyrazolones 3.
- Rossi, Elisabetta,Arcadi, Antonio,Abbiati, Giorgio,Attanasi, Orazio A.,De Crescentini, Lucia
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p. 1400 - 1402
(2007/10/03)
-
- N-Acyl-N-phenyl ureas of piperidine and substituted piperidines endowed with anti-inflammatory and anti-proliferative activities
-
Six series of N-acyl-N-phenyl ureas 1-6 of piperidine (1), and 2-ethyl- (2), 3-methyl- (3), 4-methyl- (4), 4-phenyl- (5), cis-2,6-dimethyl- (6) piperidine were synthesised and evaluated for their anti-inflammatory, anaesthetic, anti-pyretic properties. So
- Ranise, Angelo,Schenone, Silvia,Bruno, Olga,Bondavalli, Francesco,Filippelli, Walter,Falcone, Giuseppe,Rivaldi, Barbara
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p. 647 - 657
(2007/10/03)
-
- Phenylureas. Part 1. Mechanism of the basic hydrolysis of phenylureas
-
The mechanism of the hydrolytic decomposition of phenylureas in basic media in the pH range 12 to 14 is investigated. In this pH range a levelling of the rate-pH curve is observed as well as a change of the substituent influence on the hydrolysis rate. These experimental findings suggest the formation of an unreactive side product of the phenylurea in a parasitic side equilibrium at sufficiently high pH. The urea dissociates at the aryl-NH group to give its conjugate base. For the hydrolytic decomposition of phenylureas an addition-elimination mechanism is proposed as has been established for the alkaline hydrolysis of carboxylic acid esters and amides.
- Laudien,Mitzner
-
p. 2226 - 2229
(2007/10/03)
-
- Selenium-catalyzed reductive carbonylation of nitrobenzene with amines as coreagents to give unsymmetric phenylureas
-
The reductive carbonylation of nitrobenzene catalyzed by selenium to yield unsymmetric phenylureas has been studied. When secondary amines were used as coreagents, a single product, PhNHCONR2, was formed; when primary amines were chosen as coreagents, mixed products, including RNHCONHR, RNHCONHPh and PhNHCONHPh, were obtained.
- Yang, Ying,Lu, Shiwei
-
p. 4845 - 4846
(2007/10/03)
-
- α-Haloalkyl Haloformates and Related Compounds 3.1 A Facile Synthesis of Symmetrical and Unsymmetrical Ureas via Chloromethyl Carbamates
-
Chloromethyl carbamates were prepared by the reaction of chloromethyl chloroformates with amines and found to produce mono-, symmetrically or unsymmetrically di- and trisubstituted ureas including their N-hydroxy and N-alkoxy derivatives in moderate to good yield.
- Patonay, Tamas,Patonay-Peli, Erzsebet,Zolnai, Laszlo,Mogyorodi, Ferenc
-
p. 4253 - 4265
(2007/10/03)
-
- REACTIONS OF ISOTHIOCYANATES AND ISOCYANATES WITH SOME SILYLATED NITROGEN-CONTAINING NUCLEOPHILES
-
Aryl isothiocyanates and arylisocyanates react with N,O-bis(trimethylsilyl)acetamide to give N-methyl-N'-arylthioureas and ureas.Also nucleophilic additions of other aprotic nucleophiles (e.g.N-trimethylsilylimidazole, N-trimethylsilylpiperidine and N-trimethylsilylmorpholine) to the N=C=X (X=O,S) group were investigated.
- Gonda, Josef,Antalova, Zuzana
-
p. 685 - 694
(2007/10/02)
-
- KINETICS OF REACTIONS OF para-SUBSTITUTED PHENYL ISOCYANATES WITH AMINES AND ALCOHOLS
-
The reaction of para-substituted phenyl isocyanates with amines and alcohols was studied by stopped-flow method.The Hammett correlation obtained showed that the sensitivity of the above mentioned reactions toward substituent effects is the same as that of
- Danihel, Ivan,Barnikol, Falk,Kristian, Pavol
-
p. 1662 - 1670
(2007/10/02)
-
- The reaction of imidates with isocyanates
-
Derivatives of isocyanates were prepared by reaction with imidates. Fragmentation reactions and behaviour in a simple biological test were examined.
- Schweim
-
p. 319 - 321
(2007/10/02)
-
- Reactions of N- or N'-Blocked N-acylureas with Amines
-
In order to make reactions of N-acylureas with amines more selective N- or N'-blocked derivatives were prepared.Their fragmentation was examined.
- Schweim, Harald G.
-
p. 430 - 437
(2007/10/02)
-
- N-Acyl- and N-Aryl-N'-alkylidenureas as Precursors of Isocyanates or Acylisocyanates
-
Derivatives of isocyanates or acylisocyanates were prepared by reactions with ketimines.Fragmentation reactions of the product were examined.
- Schweim, Harald G.,Juergens, Sabine
-
p. 844 - 850
(2007/10/02)
-
- Preparation and Characterization of 6-Substituted 1,8-diazabicycloundec-7-ene
-
The lithium 1,8-diazabicycloundec-6-ide (1) prepared from 1,8-diazabicycloundec-7-ene (DBU) and n-butyllithium reacts with alkyl halides and carbonyl compounds such as benzophenone, acetophenone, and benzaldehyde to give 6-substituted DBU derivatives in good yields.The reaction behavior of 6-substited DBU was also investigated.
- Matsumura, Noburu,Nishiguchi, Hiroshi,Okada, Masao,Yoneda, Shigeo
-
p. 885 - 887
(2007/10/02)
-
- Preparation of Methoxythiocarbonyl Substituted Ureas
-
The alkali metal salts 4 of phenylthiocarbamic O-methyl ester (1) yields with phosgene a carbonyl chloride (5), which is a suitable starting material for the preparation of the hitherto unknown group of methoxythiocarbonyl substituted ureas.In its reactio
- Mack, Wilhelm
-
p. 165 - 170
(2007/10/02)
-
- A New Convenient Method of Desulphurisation of Thioureas and Thioamides
-
The action of thiophosgene on thioureas and thioamides provides a convenient method of desulphurisation of these compounds to ureas and amides respectively.
- Abuzar, Syed,Sharma, Satyavan,Iyer, R. N.
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p. 211 - 212
(2007/10/02)
-