479-59-4Relevant academic research and scientific papers
Acceptorless dehydrogenative condensation: synthesis of indoles and quinolines from diols and anilines
Bellezza, Delia,Zaragozá, Ramón J.,José Aurell,Ballesteros, Rafael,Ballesteros-Garrido, Rafael
supporting information, p. 677 - 683 (2021/02/06)
The use of diols and anilines as reagents for the preparation of indoles represents a challenge in organic synthesis. By means of acceptorless dehydrogenative condensation, heterocycles, such as indoles, can be obtained. Herein we present an experimental and theoretical study for this purpose employing heterogeneous catalysts Pt/Al2O3and ZnO in combination with an acid catalyst (p-TSA) and NMP as solvent. Under our optimized conditions, the diol excess has been reduced down to 2 equivalents. This represents a major advance, and allows the use of other diols. 2,3-Butanediol or 1,2-cyclohexanediol has been employed affording 2,3-dimethyl indoles and tetrahydrocarbazoles. In addition, 1,3-propanediol has been employed to prepare quinolines or natural and synthetic julolidines.
Iridium-Catalyzed Direct Cyclization of Aromatic Amines with Diols
Minakawa, Maki,Watanabe, Kouichi,Toyoda, Satoru,Uozumi, Yasuhiro
, p. 2385 - 2389 (2018/11/23)
We developed an environmentally friendly iridium-catalyzed direct cyclization of aromatic amines with diols that generates the corresponding N-heterocyclic compounds with water as the sole by-product. Thus, under conditions of 165 °C for 18 hours, the direct cyclization of N -methylanilines with 1,3-propanediol by using an IrCl 3 catalyst with rac -BINAP as a ligand in mesitylene afforded the corresponding tetrahydroquinoline derivatives with yields ranging from 73 to 83%. Under similar reaction conditions, direct cyclization of anilines with 1,3-propanediol produced the corresponding tetrahydrobenzoquinolizine derivatives with yields ranging from 26 to 76%.
Iridium-Catalyzed Sustainable Access to Functionalized Julolidines through Hydrogen Autotransfer
Labed, Amira,Jiang, Fan,Labed, Ilhem,Lator, Alexis,Peters, Marius,Achard, Mathieu,Kabouche, Ahmed,Kabouche, Zahia,Sharma, Gangavaram V. M.,Bruneau, Christian
, p. 1090 - 1096 (2015/04/14)
The straightforward and ecofriendly preparation of functionalized julolidines starting from tetrahydroquinoline, diols, and aldehydes, for which water is produced as the only side product was investigated. To achieve this task, several well-defined ruthenium and iridium complexes including three new complexes were prepared from the corresponding phosphine-sulfonates, phosphine-carboxylates, and phosphine-phosphonates. The first transformation involved in situ generation of enaminoiminium intermediates, which allowed the formation of the julolidines through formal N,C(sp2)-cyclization of tetrahydroquinoline and the propane-1,3-diols. The influence of the chelate acidity points out that [Cp?IrIII]-based catalysts (Cp?=C5Me5) featuring phosphine-carboxylate and phosphine-sulfonate ligands were suitable for the cyclization, whereas the acidic phosphinophosphonate-containing complex favored the formation of reduced N-alkylated tetrahydroquinoline. We found that substitution of the propane-1,3-diols was crucial for the generation of enaminoiminium ions, which accounts for the efficiency and selectivity of the reaction. Applying another hydrogen autotransfer process, the prepared julolidines were easily functionalized at the C2 position.
Thiophene-inserted aryl-dicyanovinyl compounds: The second generation of fluorescent molecular rotors with significantly redshifted emission and large stokes shift
Shao, Jingyin,Ji, Shaomin,Li, Xiaolian,Zhao, Jianzhang,Zhou, Fuke,Guo, Huimin
supporting information; experimental part, p. 6100 - 6109 (2011/12/03)
Fluorescent molecular rotors can be used as molecular sensors for the viscosity of a microenvironment. However, these molecular rotors are limited to 9-(dicyanovinyl)julolidine (DCVJ) and a few derivatives. Furthermore, these traditional rotors show short absorption/emission wavelengths and small Stokes shifts. To address these drawbacks, we have developed a small library of new molecular rotors for viscosity sensing, prepared by incorporating a thiophene unit into the conventional fluorescent molecular rotors with the aim of accessing molecular rotors with redshifted excitation/emission wavelengths and larger Stokes shifts compared with the known rotors. The new rotors show substantially improved photophysical properties. For example, rotor 4 shows absorption/emission wavelengths of 559/697 nm, respectively, and a very large Stokes shift of 138 nm compared with the absorption/emission wavelengths (465/503 nm) and very small Stokes shift (38 nm) of the traditional fluorescent molecular rotor DCVJ. The photophysical properties of the rotors were rationalized by DFT calculations. Thiophene-inserted aryl-dicyanovinyl molecular rotors were prepared that show substantially improved photophysical properties for the absorption/emission wavelengths and the Stokes shift. For example, rotor 4 shows absorption/emission wavelengths of 559/697 nm, respectively, and a very large Stokes shift of 138 nm compared with the traditional molecular rotor DCVJ.
A traceless perfluoroalkylsulfonyl (PFS) linker for the deoxygenation of phenols
Pan, Yijun,Holmes, Christopher P.
, p. 2769 - 2770 (2007/10/03)
(Equation presented) The synthesis of a novel perfluoroalkylsulfonyl (PFS) fluoride is described for use as a traceless linker in solid-phase organic synthesis. Attachment to the resin and subsequent coupling of a phenol affords a stable arylsulfonate that behaves as a support-bound aryl triflate. Palladium-mediated reductive cleavage of a wide variety of phenols generated the parent arenes. The resin-bound aryl triflate was shown to be stable to reductive amination conditions, and the traceless synthesis of Meclizine is reported.
Convenient synthesis of julolidines using benzotriazole methodology
Katritzky, Alan R.,Rachwal, Bogumila,Rachwal, Stanislaw,Abboud, Khalil A.
, p. 3117 - 3126 (2007/10/03)
Reaction of N,N-bis[(benzotriazol-1-yl)methyl]aniline (2) with 1-vinylpyrrolidin-2-one gives a mixture of diastereomeric 1,7-bis(2-oxopyrrolidin-1-yl)julolidines 3. After reduction of 3 with LAH, the predominant trans diastereomer of 1,7-di(pyrrolidin-1-yl)julolidine (4) is separated. Reaction of 2 with ethyl vinyl ether yields predominantly trans-1,7-di(benzotriazol-1-yl)julolidine (11). Stepwise synthesis from tetrahydroquinoline 15 gives access to julolidines with two different substituents on C-1 and C-7. Reaction of 1-[(benzotriazol-1-yl)methyl]-1,2,3,4-tetrahydroquinoline (25) with enolizable aldehydes gives a mixture of tetrahydroquinolines 26-29 which are converted into single julolidine products upon treatment with sodium hydride, LAH, or phenylmagnesium bromide. Reactions of 1,2,3,4-tetrahydroquinolines with benzotriazole and 2 molar equiv of enolizable aldehydes gives 1,2,3-trisubstituted julolidines 38-41, which with lithium aluminum hydride, sodium hydride, or a Grignard reagent produce single diastereomers of products 42, 43, and 45, respectively.
PREPARATION OF SOME DERIVATIVES OF BENZOQUINOLIZINE
Silhankova, Alexandra,Trska, Petr,Vlkova, Daniela,Ferles, Miloslav
, p. 1048 - 1056 (2007/10/02)
Reaction of 1,2,3,4-tetrahydroquinoline with 1-chloro-2,3-epoxypropane afforded 1-(3-chloro-2-hydroxypropyl)-1,2,3,4-tetrahydroquinoline (IIb) which was thermolabile and on heating in vacuo was converted into 2,3,6,7-tetrahydro-1H,5H-benzoquinolizin-2-ol (Ib).This compound reacted with acetic anhydride and p-toluenesulfonyl chloride to give 2-acetoxy-2,3,6,7-tetrahydro-1H,5H-benzoquinolizine (Ic) and 2-(p-toluenesulfonyloxy)-2,3,6,7-tetrahydro-1H,5H-benzoquinolizine (Id), respectively.N,N-Bis(3-chloro-2-hydroxypropyl)aniline (IIIb) on heating gave a mixture of cis- and trans-2,3,6,7-tetrahydro-1H,5H-benzoquinolizine-2,6-diols (Ie).The corresponding 4-methoxyaniline derivative afforded analogously a mixture of cis- and trans-9-methoxy-2,3,6,7-tetrahydro-1H,5H-benzoquinolizine-2,6-diols (If).Dehydration with potassium hydroxide converted the diols Ie into 1H,7H-benzoquinolizine (VIa), the diols If into 9-methoxy-1H,7H-benzoquinolizine (VIb).Treatment of Ib with phosphorus pentoxide led to 2,3,6,7-tetrahydro-1H,5H-benzoquinolizine (julolidine, Ia).
Amino-Claisen Rearrangement. IV. Quaternary Amino-Claisen Rearrangement of N-Allyljulolidinium Derivatives
Katayama, Hajime,Ohkoshi, Mitsuko,Kaneko, Kimiyoshi
, p. 1770 - 1779 (2007/10/02)
The amino-Claisen rearrangements of 9-unsubstituted and 9-substituted N-allyljulolidinium halides were investigated.The former compounds can be regarded as aniline derivatives in which the two ortho sites are occupied.In the latter compounds, the two ortho positions and the para position are all blocked.N-Allyljulolidinium halides rearranged into 9-allyljulolidine.However, 9-substituted N-allyljulolidinium halides gave 8-allyl-9-substituted julolidines.This meta rearrangement constitutes the first reported example of meta amino-Claisen rearrangement.The reaction pathways can be rationalized in terms of a combination of and sigmatropic rearrangements.Keywords - amino-Claisen rearrangement; meta-rearrangement; N-allyljulolidinium halide; 9-substituted-N-allyljulolidinium halide; 9-allyljulolidine; 8-allyl-9-substituted julolidine; sigmatropic rearrangement; sigmatropic rearrangement
Synthesis of Julolidines from Anilines
Katayama, Hajime,Abe, Eiichi,Kaneko, Kimiyoshi
, p. 925 - 926 (2007/10/02)
Substituted julolidines were prepared by a single step of reactions from substituted anilines.
AMINO-CLAISEN REARRANGEMENT. II. QUATERNARY AMINO-CLAISEN REARRANGEMENT OF ANILINIUM COMPOUNDS WITH ORTHO SUBSTITUENTS
Katayama, Hajime,Takatsu, Noriyuki
, p. 2465 - 2477 (2007/10/02)
Amino(N)-Claisen rearrangement of quaternary aniline derivatives with ortho substituents was investigated in relation to that of corresponding tertiary anilines.N-allylated anilinium compounds 1 with a freely rotating ortho substituent such as a methyl or methoxy group yielded mostly the deallylated products 4 along with minor amounts of rearrangement products 2 and 3.The corresponding tertiary anilines yielded ortho rearrangement products 6 together with para ones 7.The quaternary N-Claisen rearrangement of N-allylated 1,2,3,4-tetrahydroquinolinium salts 14 and indolinium salts 22 in which the ortho substituents are locked in rings afforded the ortho rearrangement products 15 and 23, respectively in good yields.N-Claisen rearrangement of the corresponding aromatic tertiary amines 18 also took place in good yield.The above rearrangements could be rationalized on the basis of mechanistic considerations.Keywords: - quaternary amino-Claisen rearrangement; mechanism; sigmatropic rearrangement; N-allyl-N,N-dimethyl-o-toluidinium bromide; N-allyl-N,N-dimethyl-o-anisidinium bromide; 1-allyl-1-methyl-1,2,3,4-tetrahydroquinolinium halides; 1-allyl-1,2-dimethylindolinium bromide; 8-allyl-1-methyl-1,2,3,4-tetrahydroquinoline; 6-allyl-1-methyl-1,2,3,4-tetrahydroquinoline; 7-allyl-1,2-dimethylindoline
