Synthesis and tautomerization of hydroxylated isoflavones bearing heterocyclic hemi-aminals

Abstract

The aminomethylation of hydroxylated isoflavones with 2-aminoethanol, 3-amino-1-propanol, 4-amino-1-butanol, and 5-amino-1-pentanol in the presence of excess formaldehyde led principally to 9-(2-hydroalkyl)-9,10-dihydro-4H,8H-chromeno[8,7-e][1,3]-oxazin-4-ones 4 and/or the tautomeric 7-hydroxy-8-(1,3-oxazepan-3-ylmethyl)-4H-chromen-4-ones 5. The ratio of these tautomers was dependent on solvent polarity, electronic effects of aryl substituents in the isoflavone and the structure of the amino alcohol. NMR studies confirmed the interconversion of tautomeric forms.

Application of Mannich bases to the synthesis of hydroxymethylated isoflavonoids as potential antineoplastic agents

“…To a stirred suspension of 2 mmol of 5c–5e 43,44 in 10 mL of isopropyl alcohol was added 0.3 mL (2.2 mmol) of bis( N,N -dimethylamino)methane. The mixture was heated at 80°C for 4–6 h and was either cooled to induce crystallization or concentrated and then triturated with hexane to induce crystallization of 7c–7e that were recrystallized from isopropanol-hexane.…”

Discovery of novel, orally bioavailable, antileishmanial compounds using phenotypic screening

“…The partial control of virulence exhibited by our HTS hits, without any optimization, strongly suggests both compounds are novel early leads for the development of orally available antileishmanials. Given the synthetic tractability of these scaffolds [ 58 , 61 ], we envision a rapid timeline for the development of optimized leads with enhanced therapeutic properties.…”

“…Thus, there has been a long-standing interest in the development of synthetic routes to access these desirable properties [ 72 , 73 ]. More recently, rapid synthetic routes to access highly substituted hydroxylated isoflavones such as 4 have been published [ 61 ].…”

Hydrolase-catalyzed asymmetric carbon–carbon bond formation in organic synthesis

“…Aldol reactions employing heterocyclic ketones as donors are also important to be explored for the fact that the structures of many natural products contain heterocyclic rings. [32][33][34] Our group evaluated the enzymatic asymmetric aldol additions of aromatic aldehydes with heterocyclic ketones in 2012. The catalytic efficiencies of some lipases, such as PPL II, lipase from wheat germ (WGL) and amano lipase A from Aspergillus niger (ANL-A), were tested for the asymmetric aldol reactions with heterocyclic ketones as donors in MeCN/water (Table 3, entries 1-3).…”