6345-67-1Relevant academic research and scientific papers
Catalyst-Controlled Stereoselective Barton–Kellogg Olefination
Schmidt, Tanno A.,Sparr, Christof
supporting information, p. 23911 - 23916 (2021/10/08)
Overcrowded alkenes are expeditiously prepared by the versatile Barton–Kellogg olefination and have remarkable applications as functional molecules owing to their unique stereochemical features. The induced stereodynamics thereby enable the controlled motion of molecular switches and motors, while the high configurational stability prevents undesired isomeric scrambling. Bistricyclic aromatic enes are prototypical overcrowded alkenes with outstanding stereochemical properties, but their stereocontrolled preparation was thus far only feasible in stereospecific reactions and with chiral auxiliaries. Herein we report that direct catalyst control is achieved by a stereoselective Barton–Kellogg olefination with enantio- and diastereocontrol for various bistricyclic aromatic enes. Using Rh2(S-PTAD)4 as catalyst, several diazo compounds were selectively coupled with a thioketone to give one of the four anti-folded overcrowded alkene stereoisomers upon reduction. Complete stereodivergence was reached by catalyst control in combination with distinct thiirane reductions to provide all four stereoisomers with e.r. values of up to 99:1. We envision that this strategy will enable the synthesis of topologically unique overcrowded alkenes for functional materials, catalysis, energy- and electron transfer, and bioactive compounds.
Electrophilic Vinylation of Thiols under Mild and Transition Metal-Free Conditions
Castoldi, Laura,Di Tommaso, Ester Maria,Gr?fen, Barbara,Olofsson, Berit,Reitti, Marcus
supporting information, p. 15512 - 15516 (2020/06/23)
The iodine(III) reagents vinylbenziodoxolones (VBX) were employed to vinylate a series of aliphatic and aromatic thiols, providing E-alkenyl sulfides with complete chemo- and regioselectivity, as well as excellent stereoselectivity. The methodology displays high functional group tolerance and proceeds under mild and transition metal-free conditions without the need for excess substrate or reagents. Mercaptothiazoles could be vinylated under modified conditions, resulting in opposite stereoselectivity compared to previous reactions with vinyliodonium salts. Novel VBX reagents with substituted benziodoxolone cores were prepared, and improved reactivity was discovered with a dimethyl-substituted core.
Metal catalyst-free amination of 2-chloro-5-nitrobenzoic acid in superheated water
Lan, Cong,Xia, Zhi-Ning,Li, Zheng-Hua,Liang, Rong-Hui
, p. 726 - 728 (2013/02/23)
A series of N-arylanthranilic acid derivatives were synthesised by amination of 2-chloro-5-nitrobenzoic acid with various arylamine in superheated water with potassium carbonate as base. Good yields were achieved within 2-3 h at 150-190 °C. The results indicated that this metal catalyst-free method is a simple, environmentally-friendly and efficient synthesis of N-phenylanthranilic acid derivatives. Furthermore, it will work with an alkylamine and phenol.
Regioselective copper-catalyzed C-N and C-S bond formation using amines, thiols and halobenzoic acids
Liu, Shuanglong,Pestano, John Paul C.,Wolf, Christian
, p. 3519 - 3527 (2008/09/19)
A regioselective method for highly efficient C-N and C-S bond formation with 2-halobenzoic acids is described. The Cu/Cu2O-catalyzed reaction is carried out in 2-ethoxyethanol or ethylene glycol diethyl ether and does not require the use of strong base or other additives. This procedure eliminates the need for acid protection, tolerates a wide range of functional groups and provides aromatic and aliphatic amines and sulfides in 81-99% yield. Georg Thieme Verlag Stuttgart.
Synthesis and crystal structures of substituted benzenes and benzoquinones as tissue factor VIIa inhibitors
Parlow, John J.,Stevens, Anna M.,Stegeman, Roderick A.,Stallings, William C.,Kurumbail, Ravi G.,South, Michael S.
, p. 4297 - 4312 (2007/10/03)
Several multistep syntheses of substituted benzenes are reported. The benzene analogues were designed such that their substitution pattern would occupy and interact with the S1, S2, and S3 pockets of the tissue Factor VIIa enzyme. A variety of chemical transformations including nucleophilic additions, reductive aminations, Stille couplings, and polymer-assisted solution-phase (PASP) techniques were used to prepare key intermediates and final products. The initial analogues identified some weakly active compounds which ultimately led to a 340 nM (IC50) tissue Factor VIIa inhibitor with selectivity over other related enzymes. The structure-activity relationship of these inhibitors and the synthetic progression from the discovery of the lead compound to the development of potent analogues will be discussed. The X-ray crystal structures of fluorobenzene 50c and benzoquinone 54 inhibitors complexed with the TF/VIIa enzyme will also be described.
Antitubercular Agents: Part IV - Synthesis of New Thiourea Derivatives Containing Diphenylsulphide-2-carboxylic Acid and Thiaxanthen-9-one Moieties
Arur, P. V.,Kulkarni, Sheshgiri N.
, p. 50 - 52 (2007/10/02)
2-Chloro-5-nitrobenzoic acid (I) on condensation with p-substituted thiophenols (II) gives 2-carboxy-4-nitro-4'-substituted-diphenyl sulphides (III).These are reduced to the corresponding amino compounds (IV) which undergo condensation with substituted ph
