20939-77-9Relevant academic research and scientific papers
Formation of a cyclic tetrahedral intermediate by the addition of water to 2-methyl-4H-3,1-benzoxazine followed by ring opening to 2-aminobenzyl acetate and 2-acetylaminobenzyl alcohol; pH-dependence of rate of reaction and product ratio
Dixon, Wendy J.,Hibbert, Frank
, p. 1035 - 1041 (1999)
Kinetic studies have shown that addition of water to protonated 2-methyl-4H-3,1-benzoxazine occurs to give a cyclic tetrahedral carbonyl addition intermediate. At pH 7.5, the unprotonated intermediate collapses to give 2-acetylaminobenzyl alcohol. The former reaction is catalysed by buffer base but the latter is uncatalysed. At pH 9-12, reaction of hydroxide ion with protonated 2-methyl-4H-3,1-benzoxazine to give 2-acetylaminobenzyl alcohol becomes important, and at pH >12, the same product is formed by reaction of hydroxide ion with unprotonated 2-methyl-4H-3,1-benzoxazine.
Metal-Free C-C/C-N/C-C Bond Formation Cascade for the Synthesis of (Trifluoromethyl)sulfonylated Cyclopenta[ b]indolines
Lázaro-Milla, Carlos,Yanai, Hikaru,Almendros, Pedro
, p. 2921 - 2926 (2021/05/05)
A bis(triflyl)ethylation [triflyl = (trifluoromethyl)sulfonyl] inserted into a sequential cyclization cascade resulted in the direct formation of gem-bis(triflyl)ated cyclopenta[b]indolines from anilide-derived allenols and alkenols. This catalyst- and irradiation-free sequence facilitated the efficient preparation of functionalized tricyclic indoline cores bearing two contiguous stereocenters. The formed cyclopenta[b]indolines can be easily transformed into a wide variety of triflylated indolines, including the tetracycle ring system found in polyveoline.
NOVEL IMIDAZO-PYRAZINE DERIVATIVES
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Page/Page column 45; 98, (2021/12/31)
The invention provides novel imidazo-pyrazine derivatives having the general formula (I), and pharmaceutically acceptable salts thereof, wherein X, m, n, and R1to R3 are as described herein: formula (I). Further provided are pharmace
Chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes using carbon-supported palladium catalytic system in water
Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
, p. 3289 - 3312 (2021/05/11)
Developing and/or modifying fundamental chemical reactions using chemical industry-favorite heterogeneous recoverable catalytic systems in the water solvent is very important. In this paper, we developed convenient, green, and efficient approaches for the chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes in the presence of the recoverable heterogeneous carbon-supported palladium (Pd/C) catalytic system in water. The utilize of the simple, effective, and recoverable catalyst and also using of water as an entirely green solvent along with relatively short reaction times and good-to-excellent yields of the desired products are some of the noticeable features of the presented synthetic protocols. Graphic abstract: [Figure not available: see fulltext.].
KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
supporting information, p. 16702 - 16707 (2020/10/27)
A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
Application of Cu(Hdmg)2 as a simple and cost-effective catalyst for the convenient one-pot reductive acetylation of aromatic nitro compounds
Zeynizadeh, Behzad,Mousavi, Hossein,Zarrin, Saviz
, p. 928 - 933 (2019/02/19)
In this article, we have developed a novel and simple one-pot reductive acetylation of aromatic nitro compounds with sodium borohydride (NaBH4) in ethyl acetate (EtOAc) under reflux conditions in the presence of the bis(dimethylglyoximato)copper(II) complex [Cu(Hdmg)2] as an efficient and cost-effective copper-containing catalyst. Notably, using the above-mentioned one-pot reaction, the corresponding acetamide derivatives were obtained in high to excellent yields.
Divergence in Ynone Reactivity: Atypical Cyclization by 3,4-Difunctionalization versus Rare Bis(cyclization)
Alcaide, Benito,Almendros, Pedro,Lázaro-Milla, Carlos,Delgado-Martínez, Patricia
supporting information, p. 8186 - 8194 (2018/06/15)
Functionalized ynones can be activated by Tf2C=CH2, which was generated in situ, to form zwitterionic species. These species were trapped in an intramolecular fashion by several nucleophiles to generate two major types of triflones in a divergent manner. Through fine-tuning of the reaction temperature, bis(triflyl)-6-membered- or (triflyl)-5-membered-fused-heterocycles were achieved in reasonable yields in a totally selective manner. In this way, bis(triflyl)flavones, bis(triflyl)thioflavones, bis(triflyl)selenoflavones, (triflyl)benzothienopyrans, (triflyl)benzoselenophenopyrans, (triflyl)vinyl aurones, and (triflyl)pyranoindoles were constructed. Conceivable mechanistic pathways were suggested on the basis of the isolation of several intermediates and the results from control experiments.
Access to Chiral Seven-Member Cyclic Amines via Rh-Catalyzed Asymmetric Hydrogenation
Li, Pan,Huang, Yi,Hu, Xinquan,Dong, Xiu-Qin,Zhang, Xumu
supporting information, p. 3855 - 3858 (2017/07/26)
A highly efficient asymmetric hydrogenation of azepine/oxazepine-type seven-member cyclic imine hydrochlorides was successfully developed using Rh/bisphosphine-thiourea ligand ZhaoPhos, affording various chiral seven-member cyclic amines with full conversions, high yields, and excellent enantioselectivities (up to 96% yield, >99% ee). Additionally, this asymmetric hydrogenation can proceed well on gram scale with excellent ee value. Moreover, control experimental results displayed that the anion-bonding interaction between the chloride ion of the substrate and thiourea motif of the ZhaoPhos played an important role to obtain excellent enantioselectivity.
A convenient allenoate-based synthesis of 2-quinolin-2-yl malonates and β-ketoesters
Selig, Philipp,Raven, William
supporting information, p. 5192 - 5195 (2014/12/11)
N-Protected o-aminobenzaldehydes smoothly react with α,γ-dialkylallenoates under Bronsted basic conditions to yield 2,3-disubstituted quinolines. This three-step reaction cascade of Michael addition, aldol condensation, and 1,3-N → C rearrangement uses the complete protecting group as a building block in a highly efficient C,C-bond formation of a new all-carbon quaternary center. Carbamate protected substrates (N-Boc, N-Cbz, N-Alloc) thus give 2-quinolin-2-yl-malonates, while amide protected substrates (N-Ac, N-Bz) afford 2-quinolin-2-yl-β-ketoesters in high yields.
Synthesis of 1-acyl-3,4-dihydroquinazoline-2(1H)-thiones by cyclization of N-[2-(isothiocyanatomethyl)phenyl] amides generated in situ from N-[2-(azidomethyl)phenyl] amides
Kobayashi, Kazuhiro,Matsumoto, Naoki
, p. 923 - 930 (2014/08/05)
An efficient method for the preparation of 1-acyl-3,4-dihydroquinazoline- 2(1H)-thiones 5 has been developed. The reaction of N-[2-(azidomethyl)phenyl] amides 3, easily prepared by a three-step sequence starting with (2-aminophenyl)methanols, with Ph
