Oxazepines and thiazepines. XIX Synthesis of optically active 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones

Optically active 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones (14–17) have been synthesizedvia resolution and chemical transformation of nitrocarboxylic acids6–9. Starting from the latter various optically active substances have been synthesized as well. Optical purity was checked by NMR spectroscopy.Dedicated to Prof. Dr.G. Snatzke on the occasion of his 60th birthday.     

Oxazepines and thiazepines,XXVIII Circular dichroism of optically active 2,3-dihydro-2-methyl-1,5-benzoxazepin-4(5H)-ones

Summary Chiroptical properties of the title compounds have been studied. The influence of the substitution pattern of the aromatic moiety and the consequence of the amide thioamide conversion are discussed as well.Dedicated to Prof. Dr. W. Wiegrebe on the occasion of his 60th birthday     

Oxazepines and thiazepines,XXI: CD-spectra of optically active 2-methyl-2,3-dihydro-1,5-benzothiazepin-4(5H)-ones and related 3-phenylthio-butyric acid derivatives

Summary Chiroptical properties of the title compounds have been studied. The influence of the substitution pattern of the aromatic ring and the configuration of the centre of chirality on the Cotton effects appearing in various wavelengths ranges are discussed.

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Oxazepine und Thiazepine, 21. Mitt.: CD-Spektren optisch aktiver 2-Methyl-2,3-dihydro-1,5-benzothiazepin-4(5H)-one und verwandter 3-Phenylthio-buttersäure-Derivate

Zusammenfassung Die chiroptischen Eigenschaften der im Titel genannten Verbindungen wurden studiert. Der Einfluß des Substitutionsmusters des aromatischen Rings und der Konfiguration des Chiralitätszentrums auf die Cotton-Effekte, die in verschiedenen Wellenlängenbereichen auftreten, werden besprochen.

     

Oxazepines and thiazepines,XX: CD-spectra of optically active 2-phenyl-2,3-dihydro-1,5-benzothiazepin-4(5H)-ones and related 3-phenylthio-3-phenyl-propionic acid derivatives,and X-ray diffraction of one phenylethylamide

Summary The absolute configuration of (–)-(1R,3S)-4 has been determined by X-ray diffraction. The UV- and CD-spectra of the title compound8 and the intermediates for its synthesis are discussed. The stronger Cotton effects can be explained by application of the exciton theory to the observed CD-couplets. The CD of the lower homologue9 of known absolute configuration is in full agreement with that of homochirally analogue8.

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Oxazepine und Thiazepine, 20. Mitt.: CD-Spektren optisch aktiver 2-Phenyl-2,3-dihydro-1,5-benzothiazepin-4(5H)-one und verwandter 3-Phenylthio-3-phenyl-propionsäure-Derivate und Röntgenstrukturanalyse eines Phenylethylamids

Zusammenfassung Die absolute Konfiguration von (–)-(1R,3S)-4 wurde durch Röntgenbeugung bestimmt. UV- und CD-Spektren der Titelverbindung8 und der Zwischenprodukte für ihre Synthese werden diskutiert. Die stärkeren Cottoneffekte können durch Anwendung der Excitontheorie auf die erhaltenen CD-Couplets erklärt werden. Der CD des niederen Homologen9 bekannter absoluter Konfiguration steht in voller Übereinstimmung mit dem des homochiral analogen8.

     

Solution-phase parallel synthesis of 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones

Practical and efficient parallel methods have been developed for the synthesis of 7,8-disubstituted 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones and 3,7,8-trisubstituted 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones. This benzothiazepin-4(5H)-one skeleton possesses three or four diversity points. Furthermore, three novel tricycles integrating a benzothiazepin-4(5H)-one scaffold with other privileged structures, such as benzimidazole, benzimidazolone, and thio-benzimidazole, were also developed. The synthetic strategy provides an efficient way to access the benzothiazepinone core, starting from commercially available 1,5-difluoro-2,4-dinitrobenzene (DFDNB), and also allows further derivation of the strategically anchored functionalities.     

Electron impact-induced fragmentation of 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones

The electron impact-induced fragmentations of 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones and some related compounds were investigated. On the basis of low- and high-resolution measurements, metastable ion studies by means of mass-analysed ion kinetic energy spectroscopy and collision-induced dissociation experiments, the main fragmentation pathways were established. The effect of methyl and phenyl substituents at the C(2) and C(3) positions of the heterocyclic ring on the fragmentations was also studied. The (1,3) ring splitting was investigated in some detail, using semi-empirical molecular orbital calculations.     

Acid-catalyzed rearrangement of 2-phenyl-2,3-dihydro-1,4-benzoxazepin-5(4H)ones

2-Phenyl-2,3-dihydro-1,4-benzoxazepin-5(4H)ones (I) were converted into 2-(o-hydroxyaryl)-5-plienyl-2-oxazolines (II) and 3,4-diliydro-4-plienyl-8-hydroxyisoearbostyrils (III) by concentrated sulfuric acid. The ratio of II and III is dependent upon substituents present in the aromatic ring of the parent benzoxazepinones.     

Novel syntheses of 2,3-dihydro-1,5-benzothiazepin-4(5h)-ones and 2h-1,4-benzothiazin-3(4h)-ones

Nucleophilic additions of alpha-mercaptoalkanoate esters and beta-mercaptoalkanoate acids to benzoquinone diimines, followed by cyclization with trifluoroacetic acid or 1,3-dicyclohexylcarbodiimide (DCC), provide novel, high-yielding syntheses of 2H-1,4-benzothiazin-3(4H)-ones (3a-f) and 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones (5a-c), respectively.     

Synthesis of 5(and 6)-nitro-4-methyl-2,3-dihydro-1h-1,5-benzo-2-diazepinones

The reaction of 4-nitro-o-phenylenediamine (I) with acetoacetic ester at room temperature under acid catalysis gives ethyl 3-(2-amino-5-nitrophenylamino)crotonate (II), which is readily cyclized to 7-nitro-4-methyl-2,3-dihydro-1H-1,5-benzo-2-diazepinone (III) on heating with alkaline agents. The reaction of I with acetoacetic ester in refluxing xylene gives isomeric 8-nitro-4-methyl-2,5-dihydro-1H-1,5-benzo-2-diazepinone (IVa) or 8-nitro-4-methyl-2,3-dihydro-1H-1,5-benzo-2-diazepinone (IVb), which are readily interconverted. The synthesis of IV is complicated by the side formation of 5-nitro-2-methylbenzimidazole (V) and thermal rearrangement of IVa and IVb to 5-nitro-1-isopropenylbenzimidazolone (VI). 6-Nitro-1-isopropenylbenzimidazolone (VII) is similarly obtained on heating III.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 696–699, May, 1972.     

1-Aryl-1-chloro-2,2,2-trifluoroethylisocyanates—convenient reagents for synthesis of 2-aryl-2-trifluoromethyl-2,3-dihydro-4H-benzo[e][1,3]oxazin-4-ones

1-Aryl-1-chloro-2,2,2-trifluoroethylisocyanates react with 3-alkoxyphenols to form N-(1-aryl-2,2,2-trifluoroethylidene)-O-(3-alkoxyphenyl)urethanes, which undergo intramolecular thermal cyclization into derivatives of 2-aryl-2-trifluoromethyl-2,3-dihydro-4H-benzo[e][1,3]oxazin-4-ones.     

A stereoselective synthesis of (R)-5-hydroxy-3-(4-methoxyphenethyl)cyclohex-2-enone,towards total synthesis of Prelunularin

A first chiral strategy for synthesis of (R)-5-hydroxy-3-(4-methoxyphenethyl) cyclohex-2-enone reported. Key transformation includes Barbier allylation, ionic hydrogenation, Jeffery reaction, Katsuki Sharpless asymmetric epoxidation, reductive opening of epoxide and ring closing metathesis.     

Crystal Structure of 5-(l-Menthyloxy)-3-Chloro-4-Pyrrolidinyl-2(5H)-Furanone

１ＩＮＴＲＯＤＵＣＴＩＯＮＯｗｉｎｇｔｏｔｈｅｉｒｗｉｄｅｏｃｃｕｒｅｎｃｅｉｎａｖａｒｉｅｔｙｏｆｂｉｏｌｏｇｉｃａｌｙａｃｔｉｖｅｎａｔｕｒａｌｐｒｏｄｕｃｔｓａｎｄｔｈｅｉｒｕｔｉｌｉｔｙａｓｖａｌｕａｂｌｅｓｙｎｔｈｅｔｉｃｉｎｔｅｒｍｅｄｉ...     

Oxazepines ano Thiazepines,XVII New Procedures for the Preparation of 2,3-Oihydro-1,5-Benzothiazepin-4(5H)-Ones Substituted in Position 2

Abstract

2,3-Dihydro-2-aryl-1,5-benzothiazepin-4(5)-ones and 2,3-disubstituted 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones have hitherto been synthesized by heating the mixture of 2-aminothiophenol and appropriately sub-stituted acrylic acids without solvent.^2–7 This is a very simple and convenient method, but because of the accompanying decompositions, the yield of the reaction is generally quite poor (20 ? 40%). For this reason, it seemed expedient to work out new procedures for the synthesis of these biologically important benzothiaze-pines. Preparation of 2,3-dihydro-2-phenyl-1,5-benzothia-zepin-4(5H)-one (20) was achieved by the ring enlargement of 1-thioflavanone⁸ but, because of the difficulties in the synthesis of the 1-thiochromanone deriva-tives in some cases, this procedure could hardly be generalized.     

An efficient route to 6-(het)aryl-2-methyl-2,3-dihydro-1H-pyridin-4-ones as potential nAChRs ligands

A new efficient pathway to synthesise 6-(het)aryl-2-methyl-2,3-dihydro-1H-pyridin-4-ones is described. This reaction sequence involved, as a key step, a Suzuki cross-coupling reaction between various boronic acids and an 6-iodo-2,3-dihydropyridin-4-one. A final deprotecting step furnished the attempted products.     

Catalytic performance of tannic acid-SO3H supported on Fe3O4@SiO2 nanoparticles for synthesis of 2,3-dihydroquinazolin-4(1H)-ones

In this paper all efforts have been devoted to develop stabilized tannic acid-SO₃H on Fe₃O₄@SiO₂ nanoparticles as the new magnetically and eco-friendly nanocatalyst. This nanocatalyst was identified using different techniques such as fourier transform infrared (FT-IR), Powder X-ray diffraction (XRD), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDXS) and thermogravimetric analysis (TGA). Catalytic performance of the catalyst in cyclocondensation reaction of anthranilamide with different aldehydes under the friendly environmentally reaction condition led to formation corresponding 2,3-dihydro-4(1H)-quinazolinones compounds in excellent yields. The catalyst could be easily recovered by an external magnet and reused 4 times without significant loss of catalytic activity.     

2-甲基-1,5-苯并硫氮杂的基态和激发态反应的研究III:2-甲基-1,5-苯并硫氮杂4-(5H)-酮与-4-甲基-1,5-苯并硫氮杂-2(3H)-酮间的互变异构

用化学反应和光谱分析证实了2-甲基(1,5)苯并硫氮杂环庚三烯-4(5H)-酮和4-甲基(1,5)苯并硫氮杂环庚三烯-2(3H)-酮是作为互变异构混合物存在的.     

Structural assignment of regioisomeric 3-[2- or 5-anilino-2-(alkylamino)phenyl]propanoic acids, 2H-1,4-benzothiazin-3(4H)-ones and 2,3-dihydro-1,5-benzothiazepin-4(5H)-ones by 1D NOE and gHMBC NMR techniques

The 1H and 13C NMR spectra of compounds 1-11 and 16-22 in CDCl3 and DMSO-d6 solutions allowed structural assignment to regioisomers 1/5 and 2/6 and their regioselective cyclization products 16-18 utilizing one- and two-dimensional NMR techniques (APT, DEPT, NOE difference, COSY, NOESY, HETCOR and gHMQC, gHMBC). Temperature-dependent 1H NMR spectra of 8-anilino-5-(4-methyl-2-pentyl)-2,3-dihydro-1,5-benzothiazepin-4(5H)-one (18) indicated a free energy of activation (deltaG++) of ca 17 kcal mol(-1) for interconversion between rotamers. The 1H and 13C NMR spectra of 20 and 22 containing two chiral centers exhibit duplication of several signals, indicating the existence of two diastereomeric forms. The structure of 4 was unambiguously confirmed by x-ray crystallography.     

Chemoenzymatic preparation of optically active 4-aryl-5-carboxy-6-methyl-3,4-dihydro-2(1H)-pyridone derivatives

A series of racemic 4-aryl-5-(tert-butoxycarbonyl)-6-methyl-3,4-dihydro-2(1H)-pyridones have been prepared by means of a modified Hantzsch reaction using commercially available starting materials. An easy removal of the tert-butyl group of these pyridones and subsequent reaction with cesium carbonate and chloromethyl 2-methylpropanoate provided us suitable substrates (±)-5 to be used in lipase-catalyzed hydrolysis reactions. Lipase B from Candida antarctica (CAL-B) was the most adequate lipase in the hydrolysis of (±)-5. Despite the low enantioselectivity values obtained (E≤12), several optically active pyridone derivatives were finally isolated with high enantiomeric excesses (ee≥91%) and moderate yields.