- Catalyst-free solventless synthesis of polysubstituted urea Method for preparing thioureas and chiral ureas and thiourea compounds
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The invention discloses a method for synthesizing polysubstituted urea, thiourea and chiral urea and thiourea compounds without catalyst without solvent, and the method comprises A contact reaction of an amine compound with a structure shown B as shown first in a non-catalyst and a solventless condition to prepare a polysubstituted urea or thiourea compound with a structure as shown C. R1 And R2 Each independently selected from a hydrocarbyl or substituted hydrocarbyl group, R3 The method is selected from H, hydrocarbyl or substituted hydrocarbyl, X is S or o. The method solves the defect that a catalyst and/or a solvent need to be used in the synthesis of urea and thiourea compounds in the prior art.
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Paragraph 0056-0062; 0098-0104
(2021/09/29)
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- Hydroamination and Hydrophosphination of Isocyanates/Isothiocyanates under Catalyst-Free Conditions
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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
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p. 5213 - 5218
(2021/10/19)
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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
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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
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supporting information
p. 997 - 1002
(2020/06/17)
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- Method for preparing asymmetric urea compound (by machine translation)
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The invention provides a vehicle CO. 2 A method. for synthesizing an asymmetric urea compound by carbonylation coupling reaction of the carbonylation reagent is: and the aromatic, aliphatic primary amine compound and the aliphatic secondary amine compound and the normal pressure (100 °C, diglyme), can be efficiently prepared by using a common Lewis base and a hydrogen silane as the accelerator/CO under mild conditions. 2 The reaction produces a corresponding asymmetric urea compound. containing different functional groups, the process being operated at atmospheric pressure CO. 2 The use of an inexpensive Lewis base and, industrial silicon waste PMHS( for the green non-toxic carbonylation reagent) avoids toxic carbonylation reagents, high pressure, as an accelerator CO. 2 , The use, of the expensive dehydrating agent and the noble metal does not need to purify and separate the intermediate, and the pure product, is obtained by simple suction filtration separation after the reaction is ended . is a high efficiency, novel synthetic method . The commercial herbicide NEBURON. is successfully prepared by using the method. (by machine translation)
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Paragraph 0043-0048; 0049-0054
(2020/03/25)
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- CaI2-Catalyzed direct transformation of: N -Alloc-, N -Troc-, and N -Cbz-protected amines to asymmetrical ureas
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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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- 2-Picolylamino(diphenylphosphinoselenoic)amide supported zinc complexes: Efficient catalyst for insertion of N–H bond into carbodiimides, isocyanates, and isothiocyanate
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We report here the hydroamination of heterocumulenes such as carbodiimides, isocyanates, and isothiocyanates by zinc complexes supported by the ligand 2-picolylamino-(diphenylphosphinoselenoic)amide [{(Ph2P-(?Se)}2NCH2(C5H4N)] (1). A series of zinc complexes [κ2-{(Ph2P-(?Se)}2NCH2(C5H4N)ZnX2] [(X?Cl (2), Br (3a), I (4)] were prepared from ligand 1 and the corresponding zinc dihalide in a 1:1 molar ratio at 60°C in a chloroform solvent. The reaction of ligand 1 and ZnBr2 in methanol yielded another zinc complex [κ2-{(Ph2P-(?Se)}2NCH2(C5H4N)ZnBr2(CH3OH)] (3b). The molecular structures of compounds 3a, 3b, and 4 were established through single-crystal X-ray diffraction analyses. The solid-state structures of all the complexes revealed a κ2- chelation through pyridine nitrogen and selenium atoms of ligand 1 to the zinc ion. Complex 2 proved to be a competent pre-catalyst for the addition of the amine N–H bond to carbodiimides, isocyanates, and isothiocyanates. The reaction scope was expanded to reactions of aliphatic and aromatic amines with phenylisocyanate and phenylisothiocyanate in toluene solvents, which proceeded rapidly at room temperature with 5 mol% catalyst loading to yield (up to 99%) the corresponding derivatives of urea and thio-urea. However, a temperature of 90°C was needed for the hydroamination of N,N′ dicyclohexylcarbodiimide. We also report the most plausible mechanism of the hydroamination reaction.
- Harinath, Adimulam,Bano, Kulsum,Ahmed, Shakil,Panda, Tarun K.
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supporting information
p. 23 - 32
(2017/09/25)
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- Synthesis of ureas in the bio-alternative solvent Cyrene
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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.
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supporting information
p. 2123 - 2128
(2017/07/24)
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- A high-yielding, expeditious, and multicomponent synthesis of urea and carbamate derivatives by using triphenylphosphine/trichloroisocyanuric acid system
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An efficient method for the synthesis of urea and carbamate derivatives from amines and alcohols is described by using triphenylphosphine (PPh3)/trichloroisocyanuric acid system. The protocol allows for the preparation of symmetrical, unsymmetrical di, tri-, and tetra-substituted ureas and carbamates and is tolerant of a wide range of functional groups. To optimize the reaction conditions, experimental variables including temperature, the concentration of amine and alcohol, solvent, and reaction time were studied. Satisfactory yields were obtained at the optimized conditions. The present methodology is experimentally simple, mild, and represents a valuable alternative to the existing methods.
- Ghodsinia, Sara S.E.,Akhlaghinia, Batool
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p. 104 - 110
(2016/01/25)
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- Hydroamination of carbodiimides, isocyanates, and isothiocyanates by a bis(phosphinoselenoic amide) supported titanium(IV) complex
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The hydroamination of heterocumulenes such as carbodiimides, isocyanates, and isothiocyanates by a bis(phosphinoselenoic amide) supported titanium(iv) complex as a precatalyst is reported here. The titanium(iv) complex [{Ph2P(Se)NCH2CH2NPPh2(Se)}Ti(NMe2)2] (1) was synthesised by the reaction of tetrakis-(dimethylamido)titanium(iv) [Ti(NMe2)4] with [{Ph2P(Se)NHCH2CH2NHPPh2(Se)}] in toluene at ambient temperature. Titanium complex 1 proved to be a competent pre-catalyst for the addition of an amine N-H bond to carbodiimides, isocyanates, and isothiocyanates. The reaction scope was expanded to reactions of aliphatic and aromatic amines with phenylisocyanates and phenylisothiocyanates in toluene solvents proceeding rapidly at room temperature with 5 mol% catalyst loadings to yield the corresponding urea and thio-urea derivatives up to 99%. However, ambient temperature was needed for hydroamination of 1,3-dicyclohexylcarbodiimide. The amine addition reactions with isocyanates showed first order kinetics with respect to catalyst 1 as well as substrates. The most plausible mechanism for the hydroamination reaction was established by isolating 1,1-dimethylphenyl urea as a side product.
- Bhattacharjee, Jayeeta,Das, Suman,Kottalanka, Ravi K.,Panda, Tarun K.
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supporting information
p. 17824 - 17832
(2016/11/18)
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- Zinc catalyzed Guanylation reaction of Amines with Carbodiimides/ Isocyanate leading to Guanidines/Urea derivatives formation
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We report the highly chemo-selective catalytic addition of N–H bonds from various aromatic amines to carbodiimides and isocyanates using (Ar-BIAO)ZnCl2 complexes [Ar-BIAO = N-(aryl)imino-acenapthenone, Ar = 2,6-Me2C6H3 (1), 2,4,6 Me3C6H2 (2), 2,6-iPr2C6H3 (3)] as the pre-catalyst to prepare guanidine and urea derivatives in 55-90% yield. The complex 3 showed higher catalytic activity than analogous complexes 1 and 2 under similar reaction conditions. The catalytic guanylation of N–H bonds with heterocumulenes displays a broad substrate scope. The amines having electron donating groups underwent higher conversion than the amines having electron withdrawing groups to afford corresponding guanidine or urea derivatives. A possible mechanism involving penta-coordinated zinc transition state for the catalytic reaction is presented. [Figure not available: see fulltext.]
- Bhattacharjee, Jayeeta,Sachdeva, Mitali,Banerjee, Indrani,Panda, Tarun K
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p. 875 - 881
(2016/07/06)
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- Imidazolin-2-iminato Ligand-Supported Titanium Complexes as Catalysts for the Synthesis of Urea Derivatives
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The reactions of tetrakis(dimethylamido)titanium(IV) [Ti(NMe2)4] with three different imidazolin-2-imines (ImRNH; R = tert-butyl (tBu), mesityl (Mes), and 2,6-diisopropylphenyl (Dipp)) afforded the corresponding titanium i
- Naktode, Kishor,Das, Suman,Bhattacharjee, Jayeeta,Nayek, Hari Pada,Panda, Tarun K.
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supporting information
p. 1142 - 1153
(2016/02/09)
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- Synthesis of unsymmetrical phenylurea derivatives via oxidative cross coupling of aryl formamides with amines under metal-free conditions
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A new synthetic approach for phenylurea derivatives involving the cross coupling of N-aryl formamides with amines through the formation of isocyanate intermediates in the presence of hypervalent iodine reagents is described.
- Reddy, Nagireddy Veera,Kumar, Pailla Santhosh,Reddy, Peddi Sudhir,Kantam, Mannepalli Lakshmi,Reddy, Kallu Rajender
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p. 805 - 809
(2015/02/19)
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- Electronic Activity Tuning of Acyclic Guanidines for Lactide Polymerization
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Novel aromatic guanidine-based organocatalysts for the ring-opening of l-lactide were synthesized and applied in comprehensive polymerization experiments and kinetic studies. The introduction of electronically active substituents led to a significant chan
- Eisenreich, Fabian,Viehmann, Philipp,Müller, Fabian,Hecht, Stefan
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p. 8729 - 8732
(2016/01/26)
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- Highly efficient synthesis of ureas and carbamates from amides by iodosylbenzene-induced hofmann rearrangement
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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
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experimental part
p. 1994 - 2000
(2012/05/05)
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- Design and synthesis of a photoswitchable guanidine catalyst
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A novel design as well as a straight-forward synthesis for a photoswitchable guanidine catalyst is reported. Intense studies of the photochromic properties demonstrated the reversible switchability of its photosensitive azobenzene moiety. Its activity in
- Viehmann, Philipp,Hecht, Stefan
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supporting information
p. 1825 - 1830,6
(2020/09/16)
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- Acetoacetanilides as masked isocyanates: Facile and efficient synthesis of unsymmetrically substituted ureas
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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
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supporting information; experimental part
p. 4220 - 4223
(2010/11/04)
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- Accelerating effects of N-aryl-N′,N′-dialkyl ureas on epoxy-dicyandiamide curing system
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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
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experimental part
p. 5298 - 5305
(2011/06/21)
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- Synthesis of unsymmetrical ureas by sulfur-assisted carbonylation with carbon monoxide and oxidation with molecular oxygen under mild conditions
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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
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experimental part
p. 2492 - 2496
(2009/12/08)
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- A simple method for the preparation of di-, tri- and tetrasubstituted non-symmetrical ureas
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The synthesis of a series of di-, tri- and tetrasubstituted non-symmetrical ureas is described. Di- and trisubstituted ureas are prepared in excellent yield by treatment of a phenyl carbamate in a self-tunable single-mode microwave synthesizer with a primary or secondary amine. The synthetically more challenging tetrasubstituted urea can be prepared using the 4-nitrophenyl carbamate and a secondary amine. Georg Thieme Verlag Stuttgart.
- Bridgeman, Eve,Tomkinson, Nicholas C. O.
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p. 243 - 246
(2007/10/03)
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- Mechanism of catalysis of the hydrolysis of a formamidinium compound
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The hydrolysis of a fluoroformamidinium ion to give a urea is subject to general base catalysis, where the addition of water is catalyzed by carboxylate monoanions (pKa 2.22-5.52) with a Bronsted coefficient of β = 0.80 through a class n mechan
- Dalby, Kevin N.
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p. 1961 - 1967
(2007/10/03)
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- Selenium-catalyzed reductive carbonylation of nitrobenzene with amines as coreagents to give unsymmetric phenylureas
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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
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p. 4845 - 4846
(2007/10/03)
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- The Synthesis of N-Substituted Ureas II: Nucleophilic Substitution of Ureas at the Carbonyl Group
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N-Arylsubstituted ureas undergo exchange of the N'-residue upon reaction with amines.Using kinetic measurements, investigation of product distribution, regioselectivity, catalysis, and substrate influences, it was shown that this reaction proceeds via a s
- Hackl, Kurt A.,Falk, Heinz
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p. 607 - 616
(2007/10/02)
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- Synthesis of Nitrogen-Containing Polycycles via Rhodium(II)-Induced Cyclization-Cycloaddition and Insertion Reactions of N-(Diazoacetoacetyl)amides. Conformational Control of Reaction Selectivity
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A series of diazoacetoacetamides, when treated with a catalytic quantity of a rhodium(II) carboxylate, were found to afford products derived from both a carbonyl ylide intermediate and intramolecular C-H insertion.With 3-(N-(diazoacetoacetyl)amino)propano
- Doyle, Michael P.,Pieters, Roland J.,Taunton, Jack,Pho, Hoan Q.,Padwa, Albert,et al.
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p. 820 - 829
(2007/10/02)
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- Ring Cleavage Reaction of 1,3-Oxazine-2,4(3H)-dione Derivatives with Amines
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The reactions of 3,6-dimethyl -1,3-oxazine-2,4(3H)-diones (1a, 1b, and 1c) with various amines were investigated under various conditions.Several reactions products were obtained such as the pyrimidines (3a, 3b, 3c, and 3d), the acetoacetamides (4a, 4b, and 4c), (4-chlorophenyl)urethane (5a), and ethyl acetoacetate (4d) with primary amines, and the acetoacetamides (4e and 4f), the urethanes (5a and 5b), the carboxamides (5c, 5d, 5e, and 5f), and the butenamides (7a, 7b, and 7c) with secondary amines.In the case of 1c with amine, alcohol used as a solvent reacted as a nucleophile to give the urethane (5a or 5b).
- Kinoshita, Toshio,Takeuchi, Kozue,Kondoh, Masaya,Furukawa, Sunao
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p. 2026 - 2029
(2007/10/02)
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