50746-65-1Relevant articles and documents
Formal Synthesis of (-)-Quinagolide: Diastereoselective Ring Expansion via a Bicyclic Aziridinium Ion Strategy to Access the Octahydrobenzo[ g]quinoline Architecture
Chavan, Subhash P.,Gonnade, Rajesh G.,Kadam, Appasaheb L.,Kawale, Sanket A.,Pisal, Mahesh M.
, p. 9344 - 9352 (2021)
The diastereoselective formal synthesis of (-)-quinagolide, a D2 receptor agonist, has been achieved. The synthesis started from l-pyroglutamic acid and relied on utilization of (a) a stereospecific catalytic hydrogenation and diastereoselective Horner-Emmons-Michael cascade to obtain functionalized prolinate, (b) a Lewis acid mediated Pummerer cyclization to construct a tricyclic fused ring system, and (c) a diastereoselective ring expansion via a bicyclic aziridinium intermediate to access the required 3-substituted piperidine scaffold.
Dipolar vinyl sulfur fluorescent dyes. Synthesis and photophysics of sulfide, sulfoxide and sulfone based D-π-A compounds
Mon?alves, Matias,Zanotto, Gabriel M.,Toldo, Josene M.,Rampon, Daniel S.,Schneider, Paulo H.,Gon?alves, Paulo F. B.,Rodembusch, Fabiano S.,Silveira, Claudio C.
, p. 8832 - 8842 (2017/02/10)
New vinyl sulfides and sulfoxides were obtained in good yields using the Horner-Wadsworth-Emmons (HWE) reaction. The vinyl sulfides and sulfoxides presented preferentially the E-stereochemistry. The respective vinyl sulfones were obtained in good yields from the vinyl sulfides by a simple oxidation step using mCPBA, solely as the E isomers. These derivatives presented absorption maxima in the UV-A region with molar absorptivity coefficients and radiative rate constant values ascribed to spin and symmetry-allowed 1π-π* electronic transitions. Experimentally, a small solvatochromic effect indicated an almost absent charge transfer character in the ground-state. A fluorescence emission in the violet-green region with a significative redshift on the maxima with increasing solvent polarity was observed, which could be related to a better electron delocalization in the excited state, as a result of an intramolecular charge transfer state. DFT and TD-DFT calculations were performed at the PBE1PBE and CAM-B3LYP levels of theory. No solvatochromic effect was observed in the ground state, but a bathochromic effect was detected in the emission maxima. Starting from sulfides to sulfones, the addition of oxygen atoms improved the charge separation, enabling an ICT state, mainly in P3 and P5. This charge separation was more efficient in the triphenylamino derivatives than among the pyrene derivatives since the first one has a better electron-donating character.
A Diels-Alder approach to biaryls (DAB): synthesis of the western portion of TMC-95
Ashburn, Bradley O.,Rathbone, Lauren K.,Camp, Elizabeth H.,Carter, Rich G.
, p. 856 - 865 (2008/09/16)
The rapid synthesis of the western biaryl portion of TMC-95 is disclosed via the use of a Diels-Alder reaction with o-nitrostyrene derivative and 1-silyloxy diene with excellent regiochemical control. Subsequent sequential substitutions of a p-iodo-phenol
