17972-14-4Relevant academic research and scientific papers
Mechanosynthesis of N-methyl imines using recyclable imidazole-based acid-scavenger: In situ formed ionic liquid as catalyst and dehydrating agent
Khaligh, Nader Ghaffari,Ling, Ong Chiu,Mihankhah, Taraneh,Johan, Mohd Rafie,Ching, Juan Joon
, p. 194 - 199 (2018/12/04)
1,1′-(1,4-Butanediyl)bis(imidazole) was prepared by a modified method and its application as an efficient promoter was demonstrated for the mechanosynthesis of N-methyl imines using ball milling as a non-conventional process under solvent-free conditions. In this new protocol design, the bis-imidazole acted as a recyclable acid-scavenging agent. This efficient approach to the N-methyl imines displays a combination of the synthetic virtues of a non-conventional condensation reaction with ecological benefits and convenience of a facile mechanosynthetic process. The current method has advantages such as reduced waste by avoiding solvent, exclusion of hazardous materials during the reaction, elimination of handling an anhydrous gas in an evacuated container or a solution of methylamine in ethanol, good yields for relatively unreactive benzaldehydes containing electron-donating substituents, short reaction times, and metal- and acid-free conditions. Furthermore, the promoter was easily regenerated and reused several times with no significant loss of activity.
Synthesis of N-methyl imines in the presence of poly(N-vinylpyridine) as a reusable solid base catalyst by a mechanochemical process
Khaligh, Nader Ghaffari,Abbo, Hanna S.,Titinchi, Salam J. J.
, p. 901 - 910 (2017/02/10)
The synthesis of N-methyl imines was performed in the presence of catalytic amounts of poly(4-vinylpyridine) in high yields and rapidly at room temperature by a ball milling process. This new method has some advantages including good yields for relatively unreactive carbonyl compounds and short reaction times as well as being green in terms of avoiding the use of toxic reagents and solvents. The major advantage of this process is that the catalyst can be easily regenerated and reused several times without any significant loss of activity.
A telescopic one-pot synthesis of β-lactam rings using amines as a convenient source of imines
Rajam?ki, Suvi H. M.,De Luca, Lidia,Capitta, Francesca,Porcheddu, Andrea
, p. 38553 - 38557 (2016/06/01)
A facile synthetic approach to substituted β-lactams was designed, using secondary benzylic amines and acid chlorides as starting materials. The reactions proceeded smoothly and all the products were obtained in good yields.
Simple and efficient one-pot solvent-free synthesis of N-methyl imines of aromatic aldehydes
Radulovi?, Niko S.,Miltojevi?, Ana B.,Vuki?evi?, Rastko D.
, p. 257 - 270 (2013/05/09)
A one-pot solvent-free synthesis of N-methyl imines in good to excellent yields was performed by grinding together aromatic aldehydes and methylamine hydrochloride in the presence of a base. The best yields were achieved when an excess of methylamine hydrochloride and inexpensive sodium hydrogen carbonate was used (usually in a molar ratio ArCHO/CH3NH2· HCl/NaHCO3 = 1:5:5), allowing the reaction to proceed for 1 h (in the case of aromatic aldehydes containing electron-withdrawing substituents) or overnight (in the case of electron-rich aldehydes). After a simple work-up (extraction with diethyl ether) the obtained products were mostly pure enough for spectral characterization. In this way, 31 N-methyl imines were prepared, among which eight were synthesized for the first time. Their structures were elucidated by spectral means (1H- and 13C-NMR, IR, MS) whenever it was possible. In the case of salicylaldehyde and 4-chlorobenzaldehyde, the synthesis of the corresponding imines was also conducted on a gram-scale with a 72% and 84% isolated yield, respectively. The present approach not only provides good to high yields, but also eliminates the disadvantages of the traditional synthesis of N-methyl imines, such as the use of hazardous solvents and more or less expensive catalysts and the necessity of work/handling with an anhydrous gas in pressurized containers.
A novel construction of 2-benzazepine scaffold based on TiCl 4-mediated tandem Mannich reaction - Aromatic electrophilic substitution
Li, Liangxi,Li, Zhiming,Wang, Quanrui
experimental part, p. 2754 - 2761 (2010/04/02)
A novel construction of 2-benzazepine derivatives based on TiCl 4-mediated tandem Mannich reaction of electron-rich benzyl iminium ions with alkenyl ethers and Friedel - Crafts-type alkylation is described. The protocol is amenable to provide the tricyclic furo[3,2-d][2]benzazepine and pyrano[3,2-d][2]benzazepine derivatives, respectively, with 2,3-dihydrofuran or 3,4-dihydro-2H-pyran as the substrates.
SAR studies of capsazepinoid bronchodilators. Part 1: The importance of the catechol moiety and aspects of the B-ring structure
Dalence-Guzman, Maria F.,Berglund, Magnus,Skogvall, Staffan,Sterner, Olov
, p. 2499 - 2512 (2008/09/21)
Capsazepine as well as its derivatives and analogues are general inhibitors of constriction of human small airways. From a systematic variation of the capsazepine structure, divided into four regions, SARs were established. This part concerns the catechol moiety of the A-ring as well as the 2,3,4,5-tetrahydro-1H-2-azepine moiety (the B-ring) of capsazepine. It is revealed that a conformational constrain (as a fused ring) is important and that compounds with a six-membered B-ring (as a 1,2,3,4-tetrahydroisoquinoline) in general are more potent than the corresponding isoindoline, 2,3,4,5-tetrahydro-1H-2-benzazepine and 2,3,4,5-tetrahydro-1H-3-benzazepine derivatives.
Synthesis of 2-alkyl-1-aryl-1,2-dihydrochromeno[2,3-c]pyrrole-3,9-dione derivatives
Vydzhak,Panchishin, S. Ya.
experimental part, p. 2391 - 2397 (2009/05/30)
A preparative procedure for the synthesis of 2-alkyl-1-aryl-1,2- dihydrochromeno[2,3-c]pyrrole-3,9-diones from methyl 4-(o-hydroxyphenyl)-2,4- dioxobutanoate, aromatic aldehyde, and aliphatic amine is described.
A new synthetic approach to dioxoaporphines - Application to the synthesis of N-methylouregidione
Hoarau, Christophe,Couture, Axel,Deniau, Eric,Grandclaudon, Pierre
, p. 2559 - 2567 (2007/10/03)
A convenient and versatile short-step synthesis of dioxoaporphines, illustrated by the first total synthesis of the alkaloid N-methylouregidione (1c), is described.
Condensation of cyclic and acyclic imines with phthalide anions. Synthesis of protoberberines and substituted 3,4-dihydro-2-methyl-1(2H)-isoquinolones
Marsden, Richard,MacLean, David B.
, p. 1392 - 1399 (2007/10/02)
3,4-Dihydroisoquinolines react with anions derived from phthalides and 3-methylphthalides in tetrahydrofuran yielding 13-hydroxy-8-oxotetrahydroprotoberberines and 13-hydroxy-13-methyl-8-oxotetrahydroprotoberberines, respectively.Only one of two possible diastereomers is formed.The lactams may be reduced to the corresponding protoberberines with lithium aluminium hydride.The reaction of the acyclic imine, 3,4-dimethoxybenzylidenemethylamine, with anions derived from phthalide, 3-phenylphthalide, and 5,6-dimethoxyphthalide, has been investigated.In all cases separable mixtures of diastereomeric substituted 3,4-dihydro-1(2H)-isoquinolones were formed.
