- PHOTOCHEMISTRY OF 4(3H)-PYRIMIDIN-4-ONES. FORMATION OF MEDIUM-RING LACTAMS
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Upon irradiation, 4(3H)-pyrimidin-4-one(1) afforded a di-imine derivate(2), which, when hydrolyzed in an acidic methanol solution, gave N-methyl acetoacetamide(3).On the other hand, the fused 4(3H)-pyrimidin-4-ones, (4) and (5), gave medium ring lactams (6) and (7), which were hydrolyzed in an acidic methanol solution to give (8) and (9), respectively.
- Hirai, Yoshiro,Yamazaki, Takao,Hirokami, Shun-ichi,Nagata, Masanori
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- Synthesis and Characterization of New Boron Compounds Using Reaction of Diazonium Tetraphenylborate with Enaminoamides
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A family of oxazaborines, diazaborinones, triazaborines, and triazaborinones was prepared by reaction of polarized ethylenes, such as β-enaminoamides, with 4-methylbenzenediazo-nium tetraphenylborates. The reaction conditions (stirring in CH2Cl2 at room temperature (Method A) or stirring with CH3COONa in CH2Cl2 at room temperature (Method B) or refluxing in the CH2Cl2/toluene mixture (Method C)) controlled the formation and relative content of these compounds in the reaction mixtures from one to three products. Substituted oxazaborines gradually rearranged into diazaborinones at 250 °C. The prepared compounds were characterized by1H NMR,13C NMR, IR, and UV–Vis spectroscopy, HRMS, or microanalysis. The structure of individual compounds was confirmed by11B NMR,15N NMR, 1D NOESY, and X-ray analysis. The mechanism of reaction of enaminoamides with 4-methylbenzenediazonium tetraphenylborate was proposed.
- Bertolasi, Valerio,Li, Bing-Han,Marek, Luká?,Sedlák, Milo?,Socha, Lubo?,Svoboda, Jan,Svobodová, Markéta
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supporting information
(2022/01/11)
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- Asymmetric Synthesis of α,β-Epoxy-?-lactams through Tandem Darzens/Hemiaminalization Reaction
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A catalytic asymmetric tandem Darzens/hemiaminalization reaction of glyoxals with α-bromo-β-esteramides or α-bromo-β-ketoamide was accomplished in the presence of a chiral N,N′-dioxide/Yb(III) complex. Various chiral α,β-epoxy-?-lactams were obtained in moderate to good yields with excellent diastereo- and enantioselectivities. The versatility of the transformation is illustrated in the formal synthesis of berkeleyamide D.
- Shen, Bin,Liu, Wen,Cao, Weidi,Liu, Xiaohua,Feng, Xiaoming
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supporting information
p. 4713 - 4716
(2019/06/27)
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- CYCLIC DIARYLBORON DERIVATIVES AS NLRP3 INFLAMMASOME INHIBITORS
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Inhibitor compounds are disclosed. The compounds are effective in the treatment of diseases or conditions in which interleukin 1 β activity is implicated. Methods of synthesis of the compounds, as well as pharmaceutical compositions comprising the compounds are also disclosed.
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Paragraph 00174
(2017/02/24)
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- A convenient method for reduction dehalogenation of α-halocarbonyl compounds using benzenethiol in K+/CH3CN system
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Benzenethiol, as a reductive agent for the dehalogenation of various α-halocarbonyl compounds, is investigated in the K+/CH3CN system. The reaction affords the reduced compounds in high yields under mild reaction conditions, especially α-chlorocarbonyl compounds. Furthermore, the reaction performed under ultrasonic irradiation greatly shortens the reaction time.
- Dong, Wei-Li,Cai, Wen-Xi,Wu, Rui,Li, Zheng-Ming,Zhao, Wei-Guang,Liu, Xing-Hai
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p. 980 - 983
(2016/07/06)
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- Zirconyl chloride: An efficient, water-tolerant, and reusable catalyst for the synthesis of N-methylamides
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ZrOCl28H2O is a highly effective, water-tolerant, and reusable catalyst for the direct condensation of carboxylic acids and N,N-dimethylurea under microwave irradiation to give the corresponding N-methylamides in moderate to excellent yields. Notably, ZrOCl 28H2O is a potentially useful green catalyst due to its low toxicity, easy availability, low cost, ease of handling, easy recovery, good activity, and reusability. Georg Thieme Verlag Stuttgart ? New York.
- Talukdar, Dhrubajyoti,Saikia, Lakhinath,Thakur, Ashim Jyoti
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experimental part
p. 1597 - 1601
(2011/08/06)
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- Inhibitors of the advanced glycosylation of proteins and methods of use therefor
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The present invention relates to compositions and methods for inhibiting nonenzymatic cross-linking (protein aging). Accordingly, a composition is disclosed which comprises an agent capable of inhibiting the formation of advanced glycosylation endproducts of target proteins by reacting with a carbonyl moiety of an early glycosylation product of such target proteins resulting from their initial glycosylation. The method comprises contacting the target protein with the composition. Both industrial and therapeutic applications for the invention are envisioned, as food spoilage and animal protein aging can be treated.
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- Effects of co-reagents on the reactions of alcohols with 6-methyl-1,3-oxazin-2,4(3H)-diones
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Primary alcohols in the presence of Triton-B react preferentially at C-6 of N-alkyl-6-methyl-1,3-oxazin-2,4(3H)-diones (1a, 1b) to give corresponding N-alkyl-3-alkoxybut-2-enamides (2) but react at C-2 of 1,3-oxazin-2,4(3H)-dione (1c) to give N-acetoacetylcarbamates (4).The modes of these reactions have been rationalised.
- Singh, Harjit,Aggarwal, Pawan,Kumar, Subodh
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p. 387 - 390
(2007/10/02)
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- Photochemistry of Pyrimidin-4-ones in Aqueous Solution and Reactions of Dewar Pyrimidinones with Water and Hydrogen Sulphide: Isolation of Reversible Hydrates and Thiazines
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Irradiation of the 2,3,6-trimethylpyrimidin-4-one (1a) in aqueous solution gave an unstable product (3a) that was observed by 1H n.m.r. spectra and reverted to the starting pyrimidin-4-one (1a) at room temperature.The reversible compound (3a) could not be separated from a large amount of the starting pyrimidin-4-one (1a) by column chromatography.Irradiation of 2,3-dialkylpyrimidin-4-ones (1e,f), 3,6-dimethylpyrimidin-4-one (1g), and 3-methylpyrimidin-4-one (1h) in aqueous acetonitrile gave (Z)-2-acetyl-3-amino-N-methylprop-2-enamide (4e), 2-(aminoethylene)-3-oxooctane-8-lactam (4f), (Z)-N-methyl-2-acetyl-3-aminoprop-2-enamide (5g), and (Z)-3-amino-2-formyl-N-methylprop-2-enamide (5h) as the major crystalline products, respectively.In order to isolate the reversible compounds (3), 1,3,6-trialkyl-5-oxo-2,6-diazabicyclohex-2-enes (2a) and (2b) and 7-oxo-9-t-butyl-6,10-diazatricyclo1,8>dec-9-ene (2c) (Dewar pyrimidinones) were prepared and treated in aqueous solutions at 15-20 deg C.The isolated reversible products were (Z)-N-acetyl-2-amino-N-methylbut-2-enamide (3a), (Z)-N-acetyl-3-amino-4,4,N-trimethylpent-2-enamide (3b), and (Z)-N-(3-amino-4,4-dimethyl-1-oxopent-2-enyl)-2-piperidone (3c).The reactions of the Dewar isomers (2b) and (2c) and 6-methyl-5-oxo-1,3-di-t-butyl-2,6-diazabicyclohex-2-ene (2d) in acetonitrile solution containing hydrogen sulphide gave 2-amino-2,3,6-trialkyl-3,4-dihydro-2H-1,3-thiazin-4-ones (8b) and (8d) and 9a-amino-5,6,7,8,9a-hexahydro-2,6-di-t-butyl-4H-pyridothiazin-4-one (8c).The hydrates (3a-c) and 1,3-thiazines (8b) and (8c) reverted quantitatively to the corresponding pyrimidin-4-ones (1a-c) at room temperature.The mechanisms and intermediates of the reactions are discussed and an X-ray crystallographic study of 3-amino-2-formyl-N-methylbut-2-enamide (4g) is reported.
- Takahashi, Tamiko,Hirokami, Shun-ichi,Nagata, Masanori,Yamazaki, Takao,Date, Tadamasa
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p. 1231 - 1239
(2007/10/02)
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- Anion-induced reactions of primary alcohols at C-6 of 3-alkyl-6-methyl-1,3-oxazine-2,4(3H)-diones:Formation of N-alkyl-3-alkoxybuten-2-amides
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Primary alcohols react at C-6 of 3-alkyl-6-methyl-1,3-oxazine-2,4(3H)-diones(2) in the presence of Triton-B or potassium thiocyanate to give N-alkyl-3-alkoxybuten-2-amides(4).
- Singh, Harjit,Aggarwal, Pawan,Kumar, Subodh
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p. 950 - 951
(2007/10/02)
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- SYNTHESIS OF 5,5'-METHYLENEBISPYRIMIDINE DERIVATIVES AND 3,4-DITHIA(6.1)(1.5) PYRIMIDINOPHANE
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Convenient syntheses of 3,6-dimethyl-1,3-oxazine-2,4(3H)-dione (3) and 5,5'-methylenebis(1-(2-hydroxyethyl)-3,6-dimethyl-2,4(1H,3H)-pyrimidinedione (5) are described.Compound 3 was prepared by the reaction of N-methylurethane with diketene, followed by alkali treatment, and 5 was obtained by treatment of 1-(2-hydroxyethyl)-3,6-dimethyl-2,4(1H,3H)-pyrimidinedione (4) with paraformaldehyde and hydrochloric acid in quantitative yield.Bromination of 5 was carried out with 47percent hydrobromic acid to give 5,5'-methylenebis(1-(2-bromoethyl)-3,6-dimethyl-2,4(1H,3H)-pyrimidinedione) (6).The reaction of 6 with thiourea afforded 7 and subsequent treatment of 7 with sodium hydroxide gave 5,5'-methylenebis(1-(2-mercaptoethyl)-3,6-dimethyl-2,4(1H,3H)-pyrimidinedione) (9).Compound 9 was oxidized to 8,11,15,18-tetramethyl-3,4-dithia(6.1)(1.5)-1,2,3,4-tetrahydro-2,4-dioxopyrimidinophane (10) with iodine under conditions of high dilution.Keywords: methylenebispyrimidine; dithiapyrimidinophane; 1,3-oxazine-2,4-dione; ring transformation; diketene; N-methylurethane; N-acetoacetyl-N-methylurethane.
- Kinoshita, Toshio,Tanaka, Hirokazu,Furukawa, Sunao
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p. 1809 - 1813
(2007/10/02)
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