- Preparation method of 2-amino-3-methyl-5-chlorobenzoic acid
-
The invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of 2-amino-3-methyl-5-chlorobenzoic acid. The preparation method provided by the invention comprises the steps of mixing m-toluic acid and nitric acid, and carrying out nitration reaction to obtain 2-nitro-3-methyl benzoic acid, wherein the mass concentration of the nitric acid is 60-75%; mixing the 2-nitro-3-methyl benzoic acid, a hydrogenation reduction reaction solvent and a hydrogenation catalyst, and carrying out hydrogenation reduction reaction in a hydrogen atmosphere to obtain 2-amino-3-methyl benzoic acid; and mixing the 2-amino-3-methyl benzoic acid, a chlorination reagent, benzoyl peroxide and a chlorination reaction solvent, and carrying out a chlorination reaction to obtain the 2-amino-3-methyl-5-chlorobenzoic acid. The preparation method provided by the invention has the advantages of cheap and easily available reaction raw materials, high product yield and high purity, and is easy for industrial production.
- -
-
Paragraph 0056; 0058; 0062; 0064; 0067; 0069; 0072; 0074
(2021/05/12)
-
- A TRANSITION METAL COMPLEX COMPOUND
-
The present invention relates to a transition metal complex (Z) (described herein), which is stable and can be effectively used as a catalyst in various chemical transformations such as to prepare chemical intermediates, agrochemical compounds as well as pharmaceutical compounds.
- -
-
Page/Page column 16
(2021/07/31)
-
- AN IMPROVED HYDROGENATION PROCESS USING A TRANSITION METAL COMPLEX CATALYST
-
The present invention relates to the process of reduction of compound of formula (II) by using a transition metal complex (Z) as a catalyst for hydrogenation reactions to get compound of formula (I). More particularly, the present invention relates to an improved process for the preparation of a compound (I) (as described herein) or a salt thereof; comprising hydrogenation of the compound (II) (as described herein) using a transition metal complex catalyst (Z).
- -
-
Page/Page column 27-28
(2021/07/31)
-
- PROCESS FOR THE PREPARATION OF CHLORANTRANILIPROLE
-
The present invention relates to two novel, efficient and one-pot methods for synthesizing chlorantraniliprole. In the first scheme, Chlorantraniliprole is prepared by a novel telescopic process starting from 3-Bromo-1-(3-chloropyridin-2-yl)-1H-pyrazole-5-carboxylic acid a key raw material-A (Key RM-A). In the second scheme, starting from Key RM-A, the process steps use of a novel variant of anthranilic acid (Methyl 2-amino-5-chloro-3-methylbenzoate), to get Chlorantraniliprole. Furthermore, the present invention also relates to the synthesis of key starting material for the synthesizing chlorantraniliprole in-situ. All the in-situ steps of the disclosed synthesis methods obtain good yield, without using any expensive reagent or base or harsh reaction conditions, which makes the process simple, environment friendly and more cost effective. With this process the production cost of chlorantraniliprole and its intermediates is substantially reduced; fewer by-products are formed during its synthesis and since it's a one-pot reaction, isolation and purification are easy to achieve.
- -
-
Page/Page column 9; 17-18
(2021/02/26)
-
- Improved synthesis process of 2-amino-5-chloro-N, 3-dimethylbenzamide
-
The invention discloses an improved synthesis process of 2-amino-5-chloro-N, 3-dimethylbenzamide, which comprises the following steps: preparing an instrument and a reagent for synthesizing 2-amino-5-chloro-N, 3-dimethylbenzamide, synthesizing 12-amino-3-methylbenzoic acid in a three-neck flask, adding ferric trichloride hexahydrate and activated carbon, stirring, heating, reacting, cooling, filtering, adding 2328-methyl-2H-3, 1-benzoxazine-2, 4(1H)-dione (MAD, 3) into a three-necked flask, adding 2-amino-3-methylbenzoic acid (MAA), pyridine and nitrile, heating under stirring until the reaction is completed, adding the reaction solution obtained in the second step into the three-neck flask, heating under stirring, then dropwise adding a mixed solution of sulfonyl chloride and acetonitrile, carrying out heat preservation reaction, then cooling to room temperature, directly filtering the reaction solution, and distilling the filtered filtrate to obtain 3-dimethylbenzamide. According tothe method for preparing the 2-amino-5-chloro-N, 3-dimethylbenzamide, the working procedure is simple and perfect in the process of preparing the 2-amino-5-chloro-N, 3-dimethylbenzamide, the preparation time can be well shortened, and the product quality is guaranteed.
- -
-
Paragraph 0033
(2021/03/11)
-
- Expedient discovery for novel antifungal leads: 1,3,4-Oxadiazole derivatives bearing a quinazolin-4(3H)-one fragment
-
Developing novel fungicide candidates are intensively promoted by the rapid emergences of resistant fungi that outbreak on agricultural production. Aiming to discovery novel antifungal leads, a series of 1,3,4-oxadiazole derivatives bearing a quinazolin-4(3H)-one fragment were constructed for evaluating their inhibition effects against phytopathogenic fungi in vitro and in vivo. Systematically structural optimizations generated the bioactive molecule I32 that was identified as a promising inhibitor against Rhizoctonia solani with the in vivo preventative effect of 58.63% at 200 μg/mL. The observations that were captured by scanning electron microscopy and transmission electron microscopy demonstrated that the bioactive molecule I32 could induce the sprawling growth of hyphae, the local shrinkage and rupture on hyphal surfaces, the extreme swelling of vacuoles, the striking distortions on cell walls, and the reduction of mitochondria numbers. The above results provided an indispensable complement for the discovery of antifungal lead bearing a quinazolin-4(3H)-one and 1,3,4-oxadiazole fragment.
- Chai, Jianqi,Chen, Min,Jin, Fei,Kong, Xiangyi,Wang, Xiaobin,Xue, Wei,Yang, Chunlong
-
-
- Preparation method of 2-amino-5-chloro-N, 3-dimethylbenzamide
-
The invention relates to a preparation method of 2-amino-5-chloro-N, 3-dimethylbenzamide. The preparation method comprises the following steps: taking 2-nitro-3-methylbenzoic acid as an initial raw material, and sequentially carrying out a reduction reaction, a chlorination reaction, an esterification reaction and an ammonolysis reaction, so as to obtain 2-amino-5-chloro-N, 3-dimethylbenzamide. The preparation method provided by the invention provides a new path for synthesis of 2-amino-5-chloro-N, 3-dimethylbenzamide, the yield of the whole path can reach 80% or above, the cost is significantly reduced, the reaction conditions of each step are mild, the number of three wastes is small, and the method is suitable for industrial production.
- -
-
Paragraph 0056-0058; 0065-0067; 0074-0076
(2020/08/29)
-
- Enantioselective synthesis of tunable chiral pyridine-aminophosphine ligands and their applications in asymmetric hydrogenation
-
A small library of tunable chiral pyridine-aminophosphine ligands were enantioselectively synthesized based on chiral 2-(pyridin-2-yl)-substituted 1,2,3,4-tetrahydroquinoline scaffolds, which were obtained in high yields and with excellent enantioselectivities via ruthenium-catalyzed asymmetric hydrogenation of 2-(pyridin-2-yl)quinolines. The protocol features a wide substrate scope and mild reaction conditions, enabling scalable synthesis. These chiral P,N ligands were successfully applied in the Ir-catalyzed asymmetric hydrogenation of benchmark olefins and challenging seven-membered cyclic imines including benzazepines and benzodiazepines. Excellent enantio- and diastereoselectivity (up to 99% ee and >20:1 dr), and/or unprecedented chemoselectivity were obtained in the asymmetric hydrogenation of 2,4-diaryl-3H-benzo[b]azepines and 2,4-diaryl-3H-benzo[b][1,4]diazepines.
- Liu, Youran,Chen, Fei,He, Yan-Mei,Li, Chenghao,Fan, Qing-Hua
-
supporting information
p. 5099 - 5105
(2019/05/29)
-
- Preparation method of 3-methyl-2-aminobenzoic acid
-
The invention discloses a preparation method of 3-methyl-2-aminobenzoic acid. The preparation method comprises the steps that 2-chloro-m-xylene is added into an acetic acid solvent for stirring, sodium acetate is added as a catalyst, the temperature is raised to 80-100 DEG C by heating, hydrogen peroxide is dropped for a reaction, after the reaction, 3-methyl-2-chlorobenzoic acid is obtained through rectification under vacuum; the 3-methyl-2-chlorobenzoic acid is added into a DMSO solvent, and catalysts of copper chloride and sodium carbonate are added and heated to 120-140 DEG C, and then ammonia is introduced and heated to 150-160 DEG C for a heat preservation of 3-6 hours, and the 3-methyl-2-aminobenzoic acid is obtained. According to the preparation method, a new design idea is provided for the synthesis of the 3-methyl-2-aminobenzoic acid, the preparation method is simple, operation is easy, the cost is low, and the preparation method is environmentally friendly.
- -
-
Paragraph 0015-0017
(2019/11/12)
-
- Br?nsted Acid-Catalyzed Asymmetric Ring-Closing Alkylation of Inert N-substituted Pyrroles with α, β-Unsaturated Ketones
-
A Chiral Br?nsted acid catalyzed asymmetric intramolecular ring-closing alkylation of inert pyrroles with α, β-unsaturated ketones has been developed. This approach gave a wide range of 4-phenyl-4,5-dihydro-6H-benzo[f]pyrrolo[1,2-a]azepin-6-ones in high yields with good enantioselectivities under mild reaction conditions. (Figure presented.).
- Wei, Zhao,Zhang, Jinlong,Yang, Huameng,Jiang, Gaoxi
-
supporting information
p. 3694 - 3697
(2019/07/12)
-
- On the Synthesis and Reactivity of 2,3-Dihydropyrrolo[1,2- a ]quinazolin-5(1 H)-ones
-
An improved, scalable synthetic route to the quinazolinone natural product 2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-one is reported. The applicability of this method to analogue synthesis and the synthesis of related natural products is explored. Finally, reactivity of the scaffold to a variety of electrophilic reagents, generating products stereoselectively, is reported.
- Sutherell, Charlotte L.,Ley, Steven V.
-
supporting information
p. 135 - 144
(2016/12/24)
-
- The therapeutic compound, use and related method (by machine translation)
-
PROBLEM TO BE SOLVED: To provide a pharmaceutical composition containing a compound or its salt which prevents or treats a central nervous system disease in which integration dysfunction syndrome and agnosia are enumerated as exemplary disorders.SOLUTION: The pharmaceutical composition includes the compound or its salt represented by chemical formula (A) which modulates striatal-enriched protein tyrosine phosphatase (STEP).
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-
Paragraph 1383; 1384
(2017/06/29)
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- Synthesis, Crystal Structure, and Biological Activity of Novel Anthranilic Diamide Insecticide Containing Propargyl Ether Group
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In search of environmentally benign insecticides with high activity, low toxicity, and low residue, a series of novel anthranilic diamide containing propargyl ether were designed and synthesized. All compounds were characterized by1H NMR spectroscopy, high-resolution mass spectrometry, or elemental analysis. The single crystal structure of 18g was determined by X-ray diffraction. The insecticidal activities against Lepidoptera pests of the new compounds were evaluated. Their insecticidal activities against oriental armyworm (Mythimna separata) and diamondback moth (Plutella xylostella) indicated that most of the compounds showed moderate to high activities at the tested concentration.
- Huang, Zhiqiang,Tong, Jun,Zhou, Sha,Xiong, Lixia,Wang, Hongxue,Zhao, Yu
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p. 1036 - 1045
(2016/07/28)
-
- The Synthesis of 5-Amino-dihydrobenzo[b]oxepines and 5-Amino-dihydrobenzo[b]azepines via Ichikawa Rearrangement and Ring-Closing Metathesis
-
The combination of Ichikawa's rearrangement and a ring-closing metathesis reaction of allyl carbamates is presented as a method for the preparation of 5-amino-substituted 2,5-dihydro-benzo[b]oxepines, 2,5-dihydro-benzo[b]azepines, and 2,5-dihydro-benzo[b]thiepins. It was demonstrated that the use of nonracemic allyl carbamates enables the synthesis of enantioenriched benzo-fused seven-membered heterocycles. Finally, it was shown that further functionalization of the obtained structures allows access to pharmacologically active 5-amino-substituted 2,3,4,5-tetrahydro-1-benzo[b]oxepine scaffolds.
- Chwastek, Monika,Pieczykolan, Micha?,Stecko, Sebastian
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p. 9046 - 9074
(2016/10/17)
-
- Synthesis and pharmacological evaluation of N-benzyl substituted 4-bromo-2,5-dimethoxyphenethylamines as 5-HT2A/2C partial agonists
-
N-Benzyl substitution of phenethylamine 5-HT2A receptor agonists has dramatic effects on binding affinity, receptor selectivity and agonist activity. In this paper we examine how affinity for the 5-HT2A/2C receptors are influenced by N-benzyl substitution of 4-bromo-2,5-dimethoxyphenethylamine derivatives. Special attention is given to the 2′ and 3′-position of the N-benzyl as such compounds are known to be very potent. We found that substitutions in these positions are generally well tolerated. The 2′-position was further examined using a range of substituents to probe the hydrogen bonding requirements for optimal affinity and selectivity, and it was found that small changes in the ligands in this area had a profound effect on their affinities. Furthermore, two ligands that lack a 2′-benzyl substituent were also found to have high affinity contradicting previous held notions. Several high-affinity ligands were identified and assayed for functional activity at the 5-HT2A and 5-HT2C receptor, and they were generally found to be less efficacious agonists than previously reported N-benzyl phenethylamines.
- Hansen, Martin,Jacobsen, Stine Engesgaard,Plunkett, Shane,Liebscher, Gudrun Eckhard,McCorvy, John D.,Br?uner-Osborne, Hans,Kristensen, Jesper Langgaard
-
supporting information
p. 3933 - 3937
(2015/01/30)
-
- THERAPEUTIC COMPOUNDS AND RELATED METHODS OF USE
-
Methods of treating disorders using compounds that modulate striatal-enriched tyrosine phosphatase (STEP) are described herein. Exemplary disorders include schizophrenia and cognitive deficit.
- -
-
Paragraph 1615
(2015/11/16)
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- Synthesis, crystal structure and biological activity of a novel anthranilic diamide insecticide containing allyl ether
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In search of environmentally benign insecticides with high activity, low toxicity and low residue, a series of novel anthranilic diamides containing allyl ether were designed and synthesized. All the compounds were characterized by 1H NMR spectroscopy, HRMS or elemental analysis. The single crystal structure of 18e was determined by X-ray diffraction. The insecticidal activities of the new compounds were evaluated. The results showed that some compounds exhibited excellent insecticidal activities against Lepidoptera pests. Among this series compounds, 18l showed 100 % larvicidal activity against Mythimna separate Walker and Plutella xylostella Linnaeus at the test concentration.
- Zhao, Yu,Xiong, Li-Xia,Xu, Li-Ping,Wang, Hongxue,Xu, Han,Li, Hua-Bin,Tong, Jun,Li, Zheng-Ming
-
p. 3071 - 3088
(2013/09/23)
-
- Substituents effects on activity of kynureninase from Homo sapiens and Pseudomonas fluorescens
-
A series of substituted kynurenines (3-bromo-dl, 3-chloro-dl, 3-fluoro-dl, 3-methyl-dl, 5-bromo-l, 5-chloro-l, 3,5-dibromo-l and 5-bromo-3-chloro-dl) have been synthesized and tested for their substrate activity with human and Pseudomonas fluorescens kynureninase. All of the substituted kynurenines examined have substrate activity with both human as well as P. fluorescens kynureninase. For the human enzyme, 3- and 5-substituted kynurenines have k cat and kcat/Km values higher than l-kynurenine, but less than that of the physiological substrate, 3-hydroxykynurenine. However, 3,5-dibromo- and 5-bromo-3-chlorokynurenine have kcat and kcat/Km values close to that of 3-hydroxykynurenine with human kynureninase. The effects of the 3-halo substituents on the reactivity with human kynureninase may be due to electronic effects and/or halogen bonding. In contrast, for the bacterial enzyme, 3-methyl, 3-halo and 3,5-dihalokynurenines are much poorer substrates, while 3-fluoro, 5-bromo, and 5-chlorokynurenine have kcat and kcat/K m values comparable to that of its physiological substrate, l-kynurenine. Thus, 5-bromo and 5-chloro-l-kynurenine are good substrates for both human as well as bacterial enzyme, indicating that both enzymes have space for substituents in the active site near C-5. The increased activity of the 5-halokynurenines may be due to van der Waals contacts or hydrophobic effects. These results may be useful in the design of potent and/or selective inhibitors of human and bacterial kynureninase.
- Maitrani, Chandan,Phillips, Robert S.
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p. 4670 - 4677
(2013/07/26)
-
- Design, synthesis and biological activities of novel anthranilic diamide insecticide containing trifluoroethyl ether
-
Two series of novel anthranilic diamide insecticide containing trifluoroethyl ether were designed and synthesized, and their structures were characterized by 1H NMR spectroscopy, elemental analysis and single crystal X-ray diffraction analysis. The insecticidal activities of the new compounds were evaluated. The results of bioassays indicated that some of these title compounds exhibited excellent insecticidal activities. The insecticidal activities of compounds 19a, 19b, 19d, 19g, 19k and 19m against oriental armyworm at 2.5 mg·kg-1 were 100%. The larvicidal activities of 19a, 19b, 19c, 19d, 19e, 19g and 19n against diamond-back moth were 100% at 0.1 mg·kg-1. Surprisingly, most of them still exhibited perfect insecticidal activity against diamond-back moth when the concentration was reduced to 0.05 mg·kg-1, which was higher than the commercialized Chlorantraniliprole.
- Zhao, Yu,Li, Yongqiang,Xiong, Lixia,Wang, Hongxue,Li, Zhengming
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p. 1748 - 1758
(2012/11/13)
-
- Twist does a twist to the reactivity: Stoichiometric and catalytic oxidations with twisted tetramethyl-IBX
-
The methyl groups in TetMe-IBX lower the activation energy corresponding to the rate-determining hypervalent twisting (theoretical calculations), and the steric relay between successive methyl groups twists the structure, which manifests in significant solubility in common organic solvents. Consequently, oxidations of alcohols and sulfides occur at room temperature in common organic solvents. In situ generation of the reactive TetMe-IBX from its precursor iodo-acid, i.e., 3,4,5,6-tetramethyl-2-iodobenzoic acid, in the presence of oxone as a co-oxidant facilitates the oxidation of diverse alcohols at room temperature.
- Moorthy, Jarugu Narasimha,Senapati, Kalyan,Parida, Keshaba Nanda,Jhulki, Samik,Sooraj, Kunnikuruvan,Nair, Nisanth N.
-
experimental part
p. 9593 - 9601
(2012/01/03)
-
- The synthesis and resolution of 2,2′-, 4,4′-, and 6,6′-substituted chiral biphenyl derivatives for application in the preparation of chiral materials
-
Various routes were examined for the synthesis of chiral biphenyl species that are substituted at the 2,2′, 4,4′ and 6,6′ positions. Because the biaryl bond is tetrasubstituted, many coupling reactions were not suitable. The most reliable coupling reaction proved to be the Ullmann, which gave the desired product in 82% yield. The products were required as the starting point for the preparation of chiral materials using these as the monomer. For this reason, a route was required that produced large quantities of both enantiomers. The two enantiomers were resolved at the penultimate step by the use of chiral HPLC. A complicating feature proved to be the necessity to have a reactive group at the 4,4′ positions, which would permit polymerization though this point. Ultimately, we employed an Ullmann coupling on a dibrominated arene, which occurred selectively at the more hindered bromine by virtue of the directing effect of an ortho ester substituent.
- Montoya-Pelaez, Pedro J.,Uh, Yoon-Seo,Lata, Christopher,Thompson, Matthew P.,Lemieux, Robert P.,Crudden, Cathleen M.
-
p. 5921 - 5929
(2007/10/03)
-
- Synthesis, Resolution, and Applications of 1,16-Dihydroxytetraphenylene as a Novel Building Block in Molecular Recognition and Assembly
-
This paper concerns the synthesis of 1,16-dihydroxytetraphenylene (DHTP) (2) by employing a novel NBS bromination route. (±)-DHTP 2 was successfully resolved into its optical antipodes and converted to (±)-1,16-bis(diphenylphosphino)tetraphenylene (BPTP) (26), whose platinum complex BPTP-PtCl2 (27) was also obtained. As a hydrogen bond donor, racemic and optically active DHTP 2 was allowed to assemble with 4,4′-bipyridine to form single crystals of good quality. X-ray Diffraction studies of these crystals revealed that the crystallographic packing of the hydrogen bonded complex between (±)-2 and 4,4′-bipyridine was different from the one formed from (S)-2 and 4,4′-bipyridine. It was found that an infinite zigzag chain with alternate chirality was formed in the assembly of (±)-2 and 4,4′-bipyridine, while (S)-2 and 4,4′-bipyridine failed to show the same assembly pattern. The reason (±)-2 formed an alternate and zigzag chain with 4,4′-bipyridine was most likely due to the inherent stability of this supramolecular assembly. The chiral recognition between 2 and optically active BINAP under the direction of platinum(II) has also been examined. 1H and 31P NMR spectroscopic studies demonstrated that there was an obvious discrimination of 2 between the enantiomers of BINAP-PtCO3.
- Wen, Jian-Feng,Hong, Wei,Yuan, Ke,Mak, Thomas C. W.,Wong, Henry N. C.
-
p. 8918 - 8931
(2007/10/03)
-
- Synthesis, resolution and structure of axially chiral atropisomeric N- arylimides
-
Reported is the synthesis and structures of a new series of axially chiral molecules based on restricted rotation. The ortho-substituted N- arylimides have enantiomeric atropisomers that are stable and separable at room temperature. The compounds are notable for their ease of synthesis as well as positioning of functionality (a carboxylic acid and an amine) in a highly asymmetric configuration. (C) 2000 Published by Elsevier Science Ltd.
- Shimizu, Ken D.,Freyer, Heather O.,Adams, Richard D.
-
p. 5431 - 5434
(2007/10/03)
-
- New, axially chiral, bimetallic catalysts for asymmetric alkylation of aldehydes with diethylzinc
-
Axially chiral bis(salicylidene)ethylenediamine (H2salen)-type ligands 3 (cf. Schemes 1 and 3) are efficient ligands for the enantioselective addition of diethylzinc to aldehydes. There is ample evidence that an active bimetallic catalyst forms an effective chiral pocket (see Fig. 2); of a series of first-row transition-metal complexes with these ligands, the most stereoselective were the Co(II) complexes (see Fig. 1). Best ee values as well as the fastest rates (see Tables 2 and 3) were obtained with these Co(II) complexes when an EtO substituent was present at C(3) of the salicylaldehyde residues of ligand 3 (R1 = EtO), i.e., complex [Co(II)(3'h)] produce d up to 93% ee with aromatic aldehydes and 78% ee for aliphatic aldehydes (see Table 4).
- Keller, Felix,Rippert, Andreas Johannes
-
p. 125 - 137
(2007/10/03)
-
- 3H-azepines and related systems. Part 5. Photo-induced ring expansions of o-azidobenzonitriles to 3-cyano- and 7-cyano-3H-azepin-2(1H)-ones
-
Unlike other aryl azides bearing electron-withdrawing ortho-substituents, o-azidobenzonitriles on photolysis in aqueous-tetrahydrofuran yield mixtures of the expected 3-cyano- and the unexpected 7-cyano-3H-azepin-2(1H)-ones. In one instance ring contraction to a 2-azabicyclo[3.2.0]hept-6-ene-3-one is noted. X-ray crystallographic data for 7-cyano- and 4-chloro-7-cyano-3H-azepin-2-one, and for the azabicycloheptenone, are presented.
- Lamara,Redhouse,Smalley,Thompson
-
p. 5515 - 5525
(2007/10/02)
-
- Benzimidazoles
-
There are described compounds of formula I, wherein one of R1 and R2 represents halogen or alkyl C1 6, and the other represents hydrogen, R3 represents alkyl C1 6, and pharmaceutically acceptable salts thereof. Processes for making the compounds and pharmaceutical compositions containing them, e.g. for the treatment of conditions in which gastric acid has a pathological role, are also disclosed.
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-
-
- Syntheses, Enrichment of Enantiomers, and Barriers to Racemization of Twisted 9,10-Phenanthrenquinones
-
The known syntheses of the 9,10-phenanthrenequinones 10a-c were improved by the chlorotrimethylsilane modification of the acyloin condensation of biaryl diesters.The novel quinones 4a, 4b, and 12 were prepared.For the first time, enantiomers (M and P) of this class of compounds were enriched semipreparatively by liquid chromatography on optically active sorbents.The barriers to thermal racemization amount to 90-130 kJ mol-1 (Table 2) and are thus higher than the barriers for the corresponding phenanthrene hydrocarbons by roughly 20 kJ mol -1.The reasons for this increase are discussed in terms of repulsive interactions in the trans ition state of helix inversion.
- Fritsch, Rainer,Hartmann, Erwin,Andert, Doris,Mannschreck, Albrecht
-
p. 849 - 856
(2007/10/02)
-
- Practical Method for the Synthesis and Optical Resolution of Axially Dissymmetric 6,6'-Dimethylbiphenyl-2,2'-dicarboxylic Acid
-
Racemic 6,6'-dimethylbiphenyl-2,2'-dicarboxylic acid (1) could be conveniently synthesized and efficiently resolved by the recrystallization of the brucine salts in satisfactory yields.Each enantiomer, thus obtained, was confirmed to be optically pure from a high-performance liquid chromatographic (HPLC) analysis on an optically active column.
- Kanoh, Shigeyoshi,Muramoto, Hiroki,Kobayashi, Natsumi,Motoi, Masatoshi,Suda, Hiroshi
-
p. 3659 - 3662
(2007/10/02)
-
- Protease inhibitors
-
This invention relates to methods of preventing or reducing the degradation of elastin and other proteins and thereby preventing or retarding the disease states caused by said degradation by administering compounds, some of which are novel, of the formula: STR1 or their pharmacologically acceptable salts.
- -
-
-
- Heterocyclic Systems Containing Bridgehead Nitrogen Atom. Part-XLVII. Syntheses of Thiazoloquinazoline and Thiazinoquinazoline
-
2-Mercapto-8-methyl-3,4-dihydroquinazolin-4-one (2a), obtained by the reaction of 3-methylanthranilic acid (1) with ammonium thiocyanate, on condensation with chloroacetic acid gives the acid (3a) which on treatment with acetic anhydride and pyridine undergoes cyclodehydration to furnish a single product to which 9-methyl-2H-thiazoloquinazolin-3,5-dione (4a) and not 5-methyl-2H-thiazoloquinazolin-3,9-dione (7a) was assigned on the basis of pmr spectral data.Similarly, (2a) on condensation with 1,2-dibromoethane and 1,3-dibromopropane yields 2,3-dihydro-9-methylthiazoloquinazolin-5-one (5a) and 4H-2,3-dihydro-10-methylthiazinoquinazolin-6-one (6), respectively.
- Gupta, G. D.,Pujari, H. K.
-
p. 1050 - 1052
(2007/10/02)
-
- Conformational Behaviour of Medium-sized Rings. Part 12. Tri-3-methyltrianthranilide
-
The stepwise synthesis of the N,N'-di- and N,N',N''-tri-substituted tri-3-methyltrianthranilides (13)-(19) are described.The amino-acid derivatives (34), (38), and (45), which are the key acyclic precursors in the synthesis of the tri-3-methyltrianthranilides, were all prepared from 2-amino-m-toluic acid (22) and 2-nitro-m-toluoyl chloride as starting materials.Tri-3-methyltrianthranilide derivatives with three equivalent N,N',N''-substituents can exist in either propeller or helical conformations.The N,N',N''-trimethyl derivative (14) adopts enantiomeric helical conformations in solution and the barrier to ring inversion is 26.8 kcal mol-1.The N,N',N''-tribenzyl derivative (19) populates both propeller and helical conformations in solution: these two conformational diastereoisomers have been separated by chromatography and isolated as crystalline compounds.Tri-3-methyltrianthranilide derivatives with two or three non-equivalent N,N',N''-substituents can, in principle, exist in either propeller or three different helical conformations.One of these three helical conformations is specifically populated in deuteriochloroform solution by compounds (13) and (15)-(17).The N,N'-dibenzyl derivative (18) populates the propeller and one helical conformation in solution: two conformational diastereoisomers have been isolated, one as an oil and the other as a crystalline compound.The N,N'-dimethyl-N''-benzyl derivative (15) undergoes spontaneous resolution when it crystallises as a 1:1 adduct from toluene.The N-methyl-N'-benzyl derivative (16) also forms a 1:1 inclusion compound on crystallisation from toluene.Although this derivative exists as only one conformational diastereoisomer of the helical type in deuteriochloroform solution, two different diastereoisomeric conformations undergo equilibration in hexadeuteriodimethyl sulphoxide with a barrier to interconversion of 16.1 kcal mol-1.
- Edge, Simon J.,Ollis, W. David,Stephanatou, Julia Stephanidou,Stoddart, J. Fraser
-
p. 1701 - 1714
(2007/10/02)
-
- Conformational Behaviour of Medium-sized Rings. Part 10. Dithiosalicylides and Trithiosalicylides
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The trithiosalicylide derivatives (8)-(11) have been synthesised and shown by temperature-dependent 1H n.m.r. spectroscopy to exist in solution as ring inverting (35a)(35b) enantiomeric helical conformations with trans-thioester linkages.The free energies of activation for these conformational changes are ca. 10 kcal mol-1 higher than those for the similar process in the corresponding trisalicylides.In contrast with the trisalicylides, the trithiosalicylides can only ring invert between enantiomeric helical conformations via intermediates containing a cis-thioester linkage.The dithiosalicylide derivatives (3)-(7) have been synthesised; the temperature dependence of the 1H n.m.r. spectrum of di-o-thiothymotide (7) has been interpreted in terms of ring inversion (40a)(40b) between enantiomeric boat conformations.Comparison of the ΔG value of 24.6 kcal mol-1 for this conformational change with that of 17.7 kcal mol-1 previously obtained for di-o-thymotide (41) suggests that cis-thioester linkages are subject to more resonance stabilisation than are cis-ester linkages.
- Guise, G. Bruce,Ollis, W. David,Peacock, Judith A.,Stephanatou, Julia Stephanidou,Stoddart, J. Fraser
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p. 1637 - 1648
(2007/10/02)
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