947-65-9Relevant academic research and scientific papers
Naphthyl ester synthesis using 1,3-dicyclohexylcarbodiimide
Zengin, Gulay,Huffman, John W.
, p. 1932 - 1934 (2004)
Dicyclohexylcarbodiimide (DCC) has been used in the past as a condensing agent in ester synthesis. Yields of ester using this route have been reported as unsatisfactory due to the formation of the by-product, an N-acylurea compound. A catalytic amount of p-toluenesulfonic acid in addition to DCC was used for the synthesis of naphthyl esters. Several other attempts to achieve esterification were also tried but were found to be unsuccessful. One method involved the in situ generation of the carboxylate anion in DMF by the use of a base followed by subsequent alkylation with an alkyl halide. Another method attempted for esterification was acylation of a carboxylic acid. The preferred method for the synthesis of a naphthyl ester was that using DCC as the condensing agent with catalytic amounts of a strong acid.
The six-membered intramolecular hydrogen bond position as a switch for inducing an excited state intramolecular proton transfer (ESIPT) in esters of o-hydroxynaphthoic acids
Catalan, Javier,Del Valle, Juan C.,Palomar, Jose,Diaz, Cristina,De Paz, Jose L. G.
, p. 10921 - 10934 (1999)
The substituted naphthalene compounds investigated in this paper, i.e., methyl 2-hydroxy-3-naphthoate (MHN23), methyl l-hydroxy-2-naphthoate (MHN12), and methyl 2-hydroxy-l-naphthoate (MHN21), show a strong intramolecular hydrogen bond {-IMHB) in their ground electronic state. The relative position of the IMHB in the naphthalene skeleton acts as a switch and controls the yield of an excited state intramolecular proton transfer (ESIPT) process. As a matter of fact, only MHN23 exhibits a proton transfer (PT) emission and possesses a theoretically proved ESIPT mechanism. The role that the ESIPT mechanism plays on the photostability of the molecule MHN23 is unravelled by comparison with the model compounds methyl salicylate (MS), MHN12, and MHN21. On one hand, the low photoreaction quantum yield, N = 0.00015, and therefore the high photostability of MS, under direct ultraviolet (UV) irradiation, has been explained due to the photophysics of its proton transfer tautomer. On the other hand, (a) the two benzene-fused ring derivatives of methyl salicylate, MHN12 and MHN21, also possess a great photostability to UV radiation, and they do not support an ESIPT mechanism; and (b) although MHN23 exhibits an excited state proton transfer, its efficiency is only of 1.8%, and the photostability is 5 times larger than that of MS. As a result, the photostability of MHN23, MHN12, and MHN21 does not rely on the photophysics of their proton transfer tautomers but on the nonradiative dynamics of their respective normal tautomers. We present experimental evidence which supports the above-mentioned statement on the existence of distinctive nonradiative channels for the molecules MHN23, MHN12, and MHN21.
Size-Driven Inversion of Selectivity in Esterification Reactions: Secondary Beat Primary Alcohols
Mayr, Stefanie,Marin-Luna, Marta,Zipse, Hendrik
, p. 3456 - 3489 (2021/03/01)
Relative rates for the Lewis base-mediated acylation of secondary and primary alcohols carrying large aromatic side chains with anhydrides differing in size and electronic structure have been measured. While primary alcohols react faster than secondary ones in transformations with monosubstituted benzoic anhydride derivatives, relative reactivities are inverted in reactions with sterically biased 1-naphthyl anhydrides. Further analysis of reaction rates shows that increasing substrate size leads to an actual acceleration of the acylation process, the effect being larger for secondary as compared to primary alcohols. Computational results indicate that acylation rates are guided by noncovalent interactions (NCIs) between the catalyst ring system and the DED substituents in the alcohol and anhydride reactants. Thereby stronger NCIs are formed for secondary alcohols than for primary alcohols.
Size-Induced Inversion of Selectivity in the Acylation of 1,2-Diols
Mayr, Stefanie,Zipse, Hendrik
supporting information, p. 18084 - 18092 (2021/12/02)
Relative rates for the Lewis base-catalyzed acylation of aryl-substituted 1,2-diols with anhydrides differing in size have been determined by turnover-limited competition experiments and absolute kinetics measurements. Depending on the structure of the anhydride reagent, the secondary hydroxyl group of the 1,2-diol reacts faster than the primary one. This preference towards the secondary hydroxyl group is boosted in the second acylation step from the monoesters to the diester through size and additional steric effects. In absolute terms the first acylation step is found to be up to 35 times faster than the second one for the primary alcohols due to neighboring group effects.
Visible Light-Promoted Photocatalytic C-5 Carboxylation of 8-Aminoquinoline Amides and Sulfonamides via a Single Electron Transfer Pathway
Sen, Chiranjit,Sahoo, Tapan,Singh, Harshvardhan,Suresh, Eringathodi,Ghosh, Subhash Chandra
, p. 9869 - 9896 (2019/08/20)
An efficient photocatalytic method was developed for the remote C5-H bond carboxylation of 8-aminoquinoline amide and sulfonamide derivatives. This methodology uses in situ generated ?CBr3 radical as a carboxylation agent with alcohol and is further extended to a variety of arenes and heteroarenes to synthesize the desired carboxylated product in moderate-to-good yields. The reaction proceeding through a single electron transfer pathway was established by a control experiment, and a butylated hydroxytoluene-trapped aryl radical cation intermediate in high-resolution mass spectrometry was identified.
Design and Synthesis of a Series of l-trans-4-Substituted Prolines as Selective Antagonists for the Ionotropic Glutamate Receptors Including Functional and X-ray Crystallographic Studies of New Subtype Selective Kainic Acid Receptor Subtype 1 (GluK1) Antagonist (2S,4R)-4-(2-Carboxyphenoxy)pyrrolidine-2-carboxylic Acid
Krogsgaard-Larsen, Niels,Delgar, Claudia G.,Koch, Karina,Brown, Patricia M. G. E.,M?ller, Charlotte,Han, Liwei,Huynh, Tri H. V.,Hansen, Stinne W.,Nielsen, Birgitte,Bowie, Derek,Pickering, Darryl S.,Kastrup, Jette Sandholm,Frydenvang, Karla,Bunch, Lennart
, p. 441 - 457 (2017/04/26)
Ionotropic glutamate receptor antagonists are valuable tool compounds for studies of neurological pathways in the central nervous system. On the basis of rational ligand design, a new class of selective antagonists, represented by (2S,4R)-4-(2-carboxyphenoxy)pyrrolidine-2-carboxylic acid (1b), for cloned homomeric kainic acid receptors subtype 1 (GluK1) was attained (Ki = 4 μM). In a functional assay, 1b displayed full antagonist activity with IC50 = 6 ± 2 μM. A crystal structure was obtained of 1b when bound in the ligand binding domain of GluK1. A domain opening of 13-14° was seen compared to the structure with glutamate, consistent with 1b being an antagonist. A structure-activity relationship study showed that the chemical nature of the tethering atom (C, O, or S) linking the pyrrolidine ring and the phenyl ring plays a key role in the receptor selectivity profile and that substituents on the phenyl ring are well accommodated by the GluK1 receptor.
Asymmetric Alkynylation of β-Ketoesters and Naphthols Promoted by New Chiral Biphenylic Iodanes
Companys, Simon,Peixoto, Philippe A.,Bosset, Cyril,Chassaing, Stefan,Miqueu, Karinne,Sotiropoulos, Jean-Marc,Pouységu, Laurent,Quideau, Stéphane
supporting information, p. 13309 - 13313 (2017/10/05)
The preparation of new chiral biphenylic λ3-iodane reagents bearing transferable alkynyl ligands is described. These reagents transfer their carbon-based ligands onto β-ketoesters with an enantiomeric excess (ee) up to 68 %, and most remarkably, enable the dearomative alkynylation of naphthols in good to high yields up to 84 % ee.
Chromatography-free, Mitsunobu-triggered heterocyclizations of salicylhydroxamic acids to 3-hydroxybenzisoxazoles
Van Eker, Daniel,Chauhan, Jay,Murphy, William A.,Conlon, Ivie L.,Fletcher, Steven
, p. 5301 - 5303 (2016/11/16)
The Mitsunobu reaction has become one of the most powerful tools to alkylate acidic pronucleophiles. A significant caveat of Mitsunobu chemistry, however, is that the reaction mixture is often plagued with purification problems owing to the phosphine oxide and hydrazine dicarboxylate by-products. In addition to the development of more readily separable Mitsunobu reagents, the product's physicochemical properties may be exploited to facilitate purification. In this regard, we present a swift and efficient preparation of 3-hydroxybenzisoxazoles by the Mitsunobu-triggered heterocyclizations of salicylhydroxamic acids, which can be isolated by an acid–base work-up. As expected, a range of functional groups was compatible with the chemistry.
Palladium-catalyzed intermolecular allylic dearomatization reaction of α-substituted β-naphthol derivatives: Scope and mechanistic investigation
Zhuo, Chun-Xiang,You, Shu-Li
, p. 2020 - 2028 (2014/07/07)
A highly efficient dearomatization reaction of α-substituted β-naphthols with excellent chemoselectivity and regioselectivity has been developed. Mechanistic studies demonstrated that the dearomatized alkylation product is the thermodynamically more stable compound. The etherification product could be further transformed to the dearomatization product.
Development of a photolabile carbonyl-protecting group toolbox
Yang, Haishen,Zhang, Xin,Zhou, Lei,Wang, Pengfei
experimental part, p. 2040 - 2048 (2011/05/06)
New salicyl alcohol derived photolabile carbonyl protecting groups have been developed, and the effect of substituents on the photochemical properties of photolabile protecting groups (PPGs) has been studied. The 3-(dimethylamino)phenyl groups at the α position prove to be important to the efficiency of the deprotection reactions, as shown in the photo reactions of the acetal 9. On the other hand, expansion of the salicyl alcohol's benzene skeleton to naphthalene does not improve the photochemical properties of PPGs. A neutral protecting protocol has been generalized to new PPGs with α,α-diaryl salicyl alcohol backbone. Thus, installation of PPGs onto aldehydes is readily achieved at 140 °C without using any other chemical reagents. These PPGs are stable under acidic conditions typical for hydrolyzing acetals and constitute orthogonal protecting groups with traditional 1,3-dioxane/1,3-dioxolane for carbonyl compounds. Highly efficient release of carbohydrate molecules is demonstrated, which can be potentially useful in site-specific release and immobilization of carbohydrates for preparation of high-density microarrays. With the enriched PPG toolbox, PPGs are divided into three subgroups based on their UV absorption profiles. PPGs from different subgroups can be sequentially removed by using different UV irradiation wavelengths. For PPGs absorbing UVA (λ >315 nm), photochemical deprotection can be carried out with sunlight in high yields.
