96125-49-4Relevant academic research and scientific papers
Regioselective syntheses of 3-hydroxy-4-aryl-3,4,5-trihydro-2H-benzo[b][1,4]diazepin-2(1H)-ones and 3-benzylquinoxalin-2(1H)-ones from arylglycidates when exposed to 1,2-diaminobenzenes
Mamedov, Vakhid A.,Mamedova, Vera L.,Syakaev, Victor V.,Voronina, Julia K.,Mahrous, Essam M.,Korshin, Dmitry E.,Latypov, Shamil K.,Sinyashin, Oleg G.
, (2020/09/10)
Representatives of two pharmacologically significant classes of compounds – 3-hydroxy-4-aryl-3,4,5-trihydro-2H-benzo[b][1,4]diazepin-2(1H)-ones and 3-benzylquinoxalin-2(1H)-ones – obtained in reactions of 1,2-diaminobenzenes with methyl 3-arylglycidates in boiling acetic acid. Substituents in arylglycidates determine the direction of processes. Electron withdrawing substituents (NO2), halogen atoms (Cl, Br, F), as well as the absence of substituents, provide the formation of benzo[b][1,4]diazepin-2(1H)-one derivatives, and electron donating groups (OMe, Me) contribute to the formation of 3-benzylquinoxalin-2(1H)-ones. As a result, a new rare representatives of 3-hydroxy-4-aryl-3,4,5-trihydro-2H-benzo[b][1,4]diazepin-2(1H)-ones were obtained and a new method for producing 3-benzylquinoxalin-2(1H)-ones has been proposed.
Sc(OTf)3-catalyzed diastereoselective Friedel-Crafts reactions of arenes and hetarenes with 3-phenylglycidates
Wilcke, David,Bach, Thorsten
supporting information; experimental part, p. 6498 - 6503 (2012/09/08)
Five different para-substituted 3-phenylglycidates (3-phenyloxirane-2- carboxylates) were prepared and subjected to reactions with arenes and hetarenes under Lewis acid catalysis. Sc(OTf)3 was found to effectively (5 mol%) promote a Friedel-Crafts reaction in nitromethane as the solvent. The reaction was shown to proceed stereoconvergently, which makes the intermediacy of a benzylic cation likely. The diastereoselectivities varied depending on the choice of the nucleophile and 3-arylglycidate. Best results were obtained with tert-butyl 3-anisylglycidate, which delivered the respective products with high syn-preference in diastereomeric ratios (d.r.) between 82:18 and >95:5. The observed selectivity can be explained by a model, according to which the intermediate benzylic cations adopt a preferred conformation, which allows for diastereoface-differentiation by the adjacent stereogenic center.
Optical resolution of a 1,5-benzothiazepine derivative, a synthetic intermediate of diltiazem, by preferential crystallization and diastereomeric salt formation
Yamada, Shin-Ichi,Yoshioka, Ryuzo,Shibatani, Takeji
, p. 1922 - 1927 (2007/10/03)
Practical preparation methods of an optically active intermediate of diltiazem, (+)-(2S,3S)-5-[2-(dimethylamino)ethyl]-2,3-dihydro-3-hydroxy-2- (4-methoxyphenyl)-1,5-benzothiazepin-4(5H)-one [(+)-7], have been developed by the use of physicochemical and chemical resolutions. 1) The salt of (+)-7 with 3-amino-4-hydroxy-benzenesulfonic acid (AHS), was found to exist as a conglomerate and could be reproducibly resolved into (+)-7·AHS and (-)- 7·AHS of 94-98% ee by a preferential crystallization procedure. 2) (+)- (1R)-3-Bromocamphor-9-sulfonic acid [(+)-BCS] was found to be an efficient resolving agent for (±)-7 and the diastereomeric resolution provided (+)- 7·(+)-BCS·2H2O salt in >43% yield and >97% ee by fractional crystallization. It is presumed that the crystal water of (+)-7·(+)- BCS·2H2O plays an important role in the selective crystallization during this efficient resolution.
A new enantioselective synthesis of (2R,3S)-3-(4-methoxyphenyl)glycidic ester via the enzymatic hydrolysis of erythro-N-acetyl-β-(4- methoxyphenyl)serine
Inoue,Matsuki,Oh-Ishi
, p. 1521 - 1523 (2007/10/02)
Enantioselective synthesis of (2R,3S)-3-(4-methoxyphenyl)glycidic ester ((2R,3S)-1) via the enzymatic hydrolysis of erythro-N-acetyl-β-(4- methoxyphenyl)serine (9) was investigated. Treatment of the obtained α- amino acid (-)-10 with NaNO2-KBr-dilute H2SO4, esterification, and subsequent oxiran-ring closure of the halohydrin gave the target compound (2R,3S)-1 with high enantiomeric excess (94% ee).
Asymmetric reduction of aromatic ketones. II. An enantioselective synthesis of methyl (2R,3S)-3-(4-methoxyphenyl)glycidate
Matsuki,Sobukawa,Kawai,Inoue,Takeda
, p. 643 - 648 (2007/10/02)
Asymmetric reduction of some 3-keto esters (6, 8, and 11) to 3-hydroxy esters (7, 9, and 12) with various chiral reducing agents was investigated. The products (9 and 12) were converted to methyl (2R,3S)-3-(4-methoxyphenyl)glycidate (2R,3S-3), a key intermediate in the practical enantioselective synthesis of diltiazem (1).
Reactions of Methyl threo-2-Acetoxy-3-chloro-3-(4-methoxyphenyl)propanoate and Methyl cis-2,3-Epoxy-3-(4-methoxyphenyl)propanoate with 3,5-Dimethoxyphenol: Potential Routes to Flavan-3-ols
Brown, Roger. F. C.,Jackson, W. Roy,McCarthy, Tom D.,Fallon, Gary D.
, p. 1833 - 1843 (2007/10/02)
Attempted syntheses of flavan-3-ols by reaction of either methyl threo-2-acetoxy-3-chloro-3-(4-methoxyphenyl)propanoate (3) or methyl cis-2,3-epoxy-3-(4-methoxyphenyl)propanoate (14) with 3,5-dimethoxyphenol failed to give the required aryl ethers.Products usually were derived from C-alkylation of the electron-rich phenol although reaction of the chloro acetate (3) with the phenoxide ion gave the furanone (5).The single-crystal X-ray structures of methyl 4-hydroxy-3-(4-methoxyphenyl)-2-(4-methoxyphenylmethyl)-5-oxo-2,5-dihydrofuran-2-carboxylate and cis-3-hydroxy-5,7-dimethoxy-4-(4-methoxyphenyl)-3,4-dihydro-2H-1-benzopyran-2-one have been determined.
Synthesis of methyl (para-methoxyphenyl)glycidate and some unusual reactions encountered on the way
Rao, A V Rama,Gaitonde, A,Rao, S Prahlada
, p. 641 - 644 (2007/10/02)
The title glycidate, the crucial chiral intermediate for the synthesis of the anti-hypertensive drug, dilitiazem has been prepared by a one-pot conversion of diol to epoxide.The dehydration of monosulphonates of diol-esters resulting in ene-sulphonate esters, has also been discussed.
A convenient synthesis of aziridine-2-carboxylic esters
Legters, Johan,Thijs, Lambertus,Zwanenburg, Binne
, p. 1 - 15 (2007/10/02)
Optically active oxirane-2-carboxylic esters, prepared from allylic alcohols employing the Sharpless epoxidation, were treated with sodium azide.The azido alcohols obtained were subsequently converted into aziridine-2-carboxylic esters by reaction with triphenylphosphine, in good yields and with high optical purity.Various racemic oxirane-2-carboxylic esters were subjected to the same sequence of reactions.
REACTION OF 4-SUBSTITUTED BENZALDEHYDES AND ACETOPHENONES WITH CHLOROACETONITRILE
Svoboda, Jiri,Kocfeldova, Zuzana,Palecek, Jaroslav
, p. 822 - 832 (2007/10/02)
Under conditions of phase-transfer catalysis or in homogeneous solution of potassium tert-butoxide the title compounds give stereoisomeric mixtures of substituted 2,3-epoxy nitriles III and IV.Alkaline hydrolysis of epoxy nitriles IV afforded the corresponding 2-arylpropanals in low yields.On treatment with methanol and potassium carbonate, epoxy nitriles III and IV were converted into epoxy esters in good yields.
Reaction of 3-Phenylglycidic Esters. Part 1. Stereoselective Opening of the Oxirane Ring of trans-3-Phenylglycidic Esters with 2-nitrothiophenols and the Effects of Various Catalysts Thereon
Hashiyama, Tomiki,Inoue, Hirozumi,Konda, Mikihiko,Takeda, Mikio
, p. 1725 - 1732 (2007/10/02)
In the reaction of 2-nitrothiophenol (2) with trans-3-phenylglycidic esters carrying various substituents on the benzene ring, both reactivity and stereoselectivity of the oxirane ring-opening of the glycidates were markedly influenced by the electronic nature of the substituents.The presence of electron-donating groups was favourable for both reactivity and the preferential formation of cis-opening products, while the reverse was true for electron-withdrawing groups.As a result of our investigation on the catalytic effect of various Lewis acids in the reaction of the 4-methoxy derivative (1) with (2), tin compounds were found to be effective catalysts for cis-opening and readily produced the threo-nitro ester (3a), a key intermediate for the synthesis of diltiazem (5).Isolation of the crystalline complex (adduct A) from the reaction of (2) with SnCl4 and its efficient catalytic activity similar to that of SnCl4 suggest that the transition state involves co-ordination of tin derivatives both with (2) and the epoxy oxygen of (1) to cause highly specific cis-opening.
