Monoimine Derived from trans-1,2-Diaminocyclohexane and Ethyl Glyoxylate: An Intermediate in Aza-Diels–Alder and Mannich Reactions

Abstract

Novel enantiopure policyclic nitrogen heterocycles have been obtained in the diastereoselective aza-Diels-Alder or Mannich reaction of dienes with imine formed in situ from ethyl glyoxylate and (1R,2R)-diaminocyclohexane.

Synthesis and Conformational Behaviour of Enantiomeric Naphthoxazinoquinoxalinone Derivatives

“…[9] Their relatively simple structure and easy accessibility among various products with quinoxalinone skeletons has allowed the discovery of a wide range of compounds that are of high interest due to their pharmacological activities, for example, antimicrobial, [10,11] antifungal, [12] antiviral, [13] anti-inflammatory, [14,15] and antitumour [16] effects. [17,18] Biologically active compounds that generate o-quinone methide intermediates are also known to be potential antitumour agents, and these reactive intermediates can alkylate DNA as a result of their nucleophilic properties. The reaction provides the corresponding adducts with goodto-high diastereoselectivity.…”

“…Furthermore, the effect of varying the reaction conditions on the stereochemistry of the reaction has also been investigated. [17,18] Biologically active compounds that generate o-quinone methide intermediates are also known to be potential antitumour agents, and these reactive intermediates can alkylate DNA as a result of their nucleophilic properties. [19] To the best of our knowledge, enantiopure compounds have not been tested in cycloaddition reactions between cyclic imines and o-quinone methides formed in situ from different substituted aminonaphthols.…”

2-Azanorbornane – a versatile chiral aza-Diels–Alder cycloadduct: preparation, applications in stereoselective synthesis and biological activity

“…Novel, modified systems can be obtained by using various substrates at the cycloaddition stage as exemplified by our stereoselective synthesis of enantiopure tri-and tetracyclic compounds bearing up to 5 stereogenic centers (example is shown in Scheme 70). 163 The known modifications of the 2-azabicyclo[2.2.1]heptane derivatives include transformations of the bicyclic skeleton, stereoselective ring opening, and alteration of substituents. The synthesis of bisfunctional ligands with a possible control of the mutual position and character of donor groups remains the most important since 2-azanorbornane serves as a rigid chiral scaffold and as an additional source of discrimination in the course of catalytic reactions.…”

“…161 Scheme 70 Synthesis of the enantiopure tetracyclic compound using (1R,2R)-1,2-diaminocyclohexane as a chirality source. 163 A 2-azanorbornene fragment in the tetracyclic product 155 indicated.…”

Chemistry of α-Oxoesters: A Powerful Tool for the Synthesis of Heterocycles

“…Also, reaction of 574 with phenol derivatives proceeded via Mannich-type reaction to afford the corresponding Mannich adducts 575 (Scheme 172). 269,270 Reaction of glycine amide hydrochloride with equimolar amount of substituted benzaldehydes in EtOH in the presence of Na 2 CO 3 at 60−70 °C, followed by addition of 1 equiv of methyl benzoylpyruvate and heating under reflux conditions for 5 min, and then standing at room temperature for 24 h, afforded 3-arylidene-5-(benzoylmethylene)piperazine-2,6-diones 577 in 20−25% yields (Scheme 173). 271 A series of 3-oxopiperazine-2-carboxamides 578, 3-oxotetrahydroquinoxaline-2-carboxamides 579, and 3,6-dioxopiper- azine-2-carboxamides 580 were prepared by Ugi-deprotectioncyclization reactions sequence.…”