- Cooperative Binding of Divalent Diamides by N-Alkyl Ammonium Resorcinarene Chlorides
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N-Alkyl ammonium resorcinarene chlorides, stabilized by an intricate array of hydrogen bonds leading to a cavitand-like structure, bind amides. The molecular recognition occurs through intermolecular hydrogen bonds between the carbonyl oxygen and the amide hydrogen of the guests and the cation-anion circular hydrogen-bonded seam of the hosts, as well as through CH7mellip;π interactions. The N-alkyl ammonium resorcinarene chlorides cooperatively bind a series of di-acetamides of varying spacer lengths ranging from three to seven carbons. Titration data fit either a 1:1 or 2:1 binding isotherm depending on the spacer lengths. Considering all the guests possess similar binding motifs, the first binding constants were similar (K1:102M-1) for each host. The second binding constant was found to depend on the upper rim substituent of the host and the spacer length of the guests, with the optimum binding observed with the six-carbon spacer (K2:103M-2). Short spacer lengths increase steric hindrance, whereas longer spacer lengths increase flexibility thus reducing cooperativity. The host with the rigid cyclohexyl upper rim showed stronger binding than the host with flexible benzyl arms. The cooperative binding of these divalent guests was studied in solution through 1HNMR titration studies and supplemented by diffusion-ordered spectroscopy (DOSY), X-ray crystallography, and mass spectrometry. Cooperative guests: N-Alkyl ammonium resorcinarene chlorides cooperatively bind a series of homoditopic alkyl diamides of varying spacer lengths (see figure). The highest binding was observed with the six-carbon spacer guest. The cooperative binding of these divalent guests was studied in solution by using 1HNMR titration studies and supplemented by diffusion-ordered NMR spectroscopy (DOSY), X-ray crystallography, and mass spectrometry.
- Beyeh, N. Kodiah,Ala-Korpi, Altti,Pan, Fangfang,Jo, Hyun Hwa,Anslyn, Eric V.,Rissanen, Kari
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- Amide exchange reaction: A simple and efficient CuO catalyst for diacetamide synthesis
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A highly copper-catalysed amide exchange reaction of hexamethylenediamine (HDA) with CH3CN and H2O for the synthesis of hexamethylenebisacetamide (HMBA) without an organic solvent or gas protection was developed. 100% HDA conversion and >99% HMBA selectivity was obtained. X-ray diffraction, scanning emission microscopy, and temperature-programmed reduction of hydrogen were used to characterize the structural properties of the catalyst. The reaction mechanism was also investigated.
- Li, Qinghe,Wang, Peixue,Deng, Youquan
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p. 40890 - 40894
(2016/05/19)
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- Method for preparing diamide under catalysis of non-noble metal
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The invention discloses a method for preparing diamide under catalysis of non-noble metal. Diamine, a nitrile compound and water are taken as raw materials and subjected to an acylation reaction in presence of a non-noble metal catalyst for preparation of diamide, wherein the non-noble metal catalyst is a transition metal oxide or a supporting transition metal oxide, the transition metal oxide adopts CuO or Cu2O, and a support adopts SiO2 or Al2O3. The diamine conversion rate is 99% or higher and the selectivity is 99% or higher under optimized reaction conditions. The method has the advantages of short reaction time, available catalyst, low catalyst cost, high conversion rate, high reaction selectivity and the like and has very high actual application value.
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Paragraph 0018
(2018/02/04)
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- COMPOSITIONS AND METHODS FOR MODULATING HEXIM1 EXPRESSION
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The potency of a series of Hexamethylene bis-acetamide (HMBA) derivatives of formula I, that induce Hexamethylene bis-acetamide inducible protein 1 (HEXIM1 ) was determined in cancer cells. The method of inducing HEXIM1 expression and cell differentiation in cancer and HIV cells are disclosed. Optimization of HMBA analogs that are symmetrical and unsymmetrical are also discussed.
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Paragraph 00187
(2015/09/23)
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- Lead optimization of HMBA to develop potent HEXIM1 inducers
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The potency of a series of Hexamethylene bis-acetamide (HMBA) derivatives inducing Hexamethylene bis-acetamide inducible protein 1 (HEXIM1) was determined in LNCaP prostate cancer cells. Several compounds with unsymmetrical structures showed significantly improved activity. Distinct from HMBA, these analogs have increased hydrophobicity and can improve the short half-life of HMBA, which is one of the factors that have limited the application of HMBA in clinics. The unsymmetrical scaffolds of the new analogs provide the basis for further lead optimization of the compounds using combinatorial chemistry strategy.
- Zhong, Bo,Lama, Rati,Ketchart, Wannarasmi,Montano, Monica M.,Su, Bin
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p. 1410 - 1413
(2014/03/21)
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- Synthesis of (2-alkylthiothiazolin-5-yl)methyl dodecanoates via tandem radical reaction
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A series of (2-alkylthiothiazolin-5-yl)methyl dodecanoates was synthesized from various alkyl N-allylcarbamodithioates and dilauroyl peroxide via a tandem radical hydrogen-abstraction-cyclization-substitution/combination reaction with a 5-exo-trig radical cyclization as a key step. The current route is the first, convenient, and efficient synthesis of (2-alkylthiothiazolin-5-yl)methanol derivatives. The Royal Society of Chemistry.
- Kakaei, Saeed,Xu, Jiaxi
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p. 5481 - 5490
(2013/08/28)
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- IMPROVED NEUTRALIZATION OF ISOPHORONE NITRILE SYNTHESIS PRODUCTS
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The invention relates to a method for producing 3-cyano-3,5,5- trimethylcyclohexanone (isophorone nitrile) by reacting isophorone with hydrogen cyanide in the presence of a base as a catalyst. A special sulfonic acid or a special carboxylic acid is added to the resulting raw isophorone nitrile product which is then distilled. The invention further relates to the use of a special sulfonic acid or a special carboxylic acid as a neutralizing agent prior to distilling a raw isophorone nitrile product which is obtained by reacting isophorone with hydrogen cyanide in the presence of a base as a catalyst in order to prevent precipitations during neutralization of the base used as a catalyst with an acid.
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- Preparation of 3-cyano-3, 5, 5-trimethylcyclohexanone
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In a process for preparing 3-cyano-3,5,5-trimethylcyclohexanone by reacting isophorone with hydrogen cyanide at from 80 to 220° C. in the presence of a catalyst, the reaction is carried out in the presence of the betaine 1,3-dimethylimidazolium-4-carboxylate.
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- Variable NMR spin-lattice relaxation times in secondary amides: Effect of ramachandran angles on librational dynamics
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Deuterium NMR spin-lattice relaxation times (T1Z) of N-deuterated microcrystalline secondary amides vary from less than 1 s to more than 500 s at room temperature. The main motion effecting relaxation is an out-of-plane libration of the amide, as indicated by temperature-dependent line shapes and anisotropic relaxation spectra. Over 25 amides were measured; they vary with respect to side chain sterics, hydrogen bond lengths, hydrogen bond geometry, and crystal packing. The temperature-dependent deuterium line shape and anisotropic relaxation rates indicate an out-of-plane angular deflection of approximately 10°; the angle is probably similar for the rapidly and slowly relaxing amides, while the apparent time constant for the motion probably varies dramatically. Deuterons in methylene groups on both sides of the amide group for caprylolactam and caprolactam also indicate an out-of-plane libration with relaxation rates faster than that of the amide deuteron, probably because the angular extent of the distortion is greater for the flanking α-deuteron than for the amide deuteron. Carbon relaxation measurements on lauryllactam indicate that the whole molecule librates to a comparable extent. Temperature-dependent relaxation rates for caprylolactam and caprolactam showed nonArrhenius monotonic increases in the relaxtion rates with increasing temperature, as expected for libration dynamics; furthermore the quadrupolar relaxation measurements support the assumption that the dominant spectral density contribution is above the Larmor frequency (i.e. T1Q is longer than T1Z). In aggregate, the data indicate that the motion effecting amide relaxation is a low-amplitude libration involving the entire molecule. Previous work on the librations of amides suggested that these librations are pronounced on the NMR time scale when the substance is near a phase transition; we report here that there is additionally a relation between the extent of libration and the structure. Comparison of the relaxation times to structures indicates that only amides with flanking alkyl groups on both sides (larger than a methyl group) exhibit extensive libration; furthermore only those amides with both flanking dihedral angles, φ{C2C1-NC(=O)} and ψ{N(O=)C-C1′C2′}, near -60° (～±40°) have fast spin-lattice relaxation. On the other hand, correlation between the deuterium relaxation times and hydrogen bond length nor geometry nor crystal packing was observed. Variation in the electronic structures of the conjugated amide groups was indirectly probed by measuring the chemical shift anisotropy of the amide carbonyl carbon, the deuterium quadrupolar coupling constant, and vibrational frequencies. These parameters did not vary dramatically, indicating that the electronic structure is not strongly variable; the modest variation did not correlate with deuterium relaxation rates. The chemical shift tensor elements were δ11 = 91.4 ±5, δ22 = 185 ± 8, and δ33 = 245 ± 3 ppm, the quadrupolar coupling constant and its anisotropy were 203 ± 10 kHz and 0.15 ± 0.02, the NH stretch frequency was 3300 ± 42 cm-1, and the carbonyl stretch frequency was 1644 ± 25 cm-1. We suggest a model in which the shape of the local potential associated with flanking alkyl groups leads to "overdamping" of the amide librational mode and generates slower (nanosecond) components in the vibrational frequency spectrum.
- Williams, John C.,McDermott, Ann E.
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p. 6248 - 6259
(2007/10/03)
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- Process for producing amines
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A process is disclosed for producing an amine by carrying out a reductive amination of a cyclic ketone or by carrying out a reduction of an imino derivative of a cyclic ketone to the corresponding amine which process is characterized in using a cobalt catalyst containing a carbonate of an alkaline earth metal and/or lanthanum oxide.
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- Process for the preparation of 3-aminomethyl-3,5,5-trialkylcyclohexylamine
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A process for the preparation of a 3-aminomethyl-3,5,5-trialkylcyclohexylamine, which comprises hydrogenating 3-cyano-3,5,5-trialkylcyclohexylamine in the presence of ammonia and a ruthenium-cobalt catalyst.
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- A Simple and Economic Synthesis of Monoacylated Alkanediamines by Thermal Transamidation
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N-(ω-Aminoalkyl)amides 2 are easily synthesized by heating mixtures of excess α,ω-alkanediamines 1 and primary amides to temperatures between 150 deg C and 200 deg C, at which thermal transamidation occurs.Under the reaction conditions ammonia is released, and 2 is in equilibrium with the alkanediamine 1 and the α,ω-bis(acylamino)alkane 3.Thus, thermal transamidation is a practicable way to overcome the problem of diacylation which appears as an often recognized problem even in the latest literature.
- Zaragoza-Doerwald, Florencio,Kiedrowski, Guenter von
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p. 917 - 918
(2007/10/02)
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