Stereoselective synthesis of 2-hydroxymorpholines and aminodiols via a three-component boro-Mannich reaction

Discovery of morpholine-based aryl sulfonamides as Nav1.7 inhibitors

Replacement of the piperidine ring in the lead benzenesulfonamide Na_v1.7 inhibitor 1 with a weakly basic morpholine core resulted in a significant reduction in Na_v1.7 inhibitory activity, but the activity was restored by shortening the linkage from methyleneoxy to oxygen. These efforts led to a series of morpholine-based aryl sulfonamides as isoform-selective Na_v1.7 inhibitors. This report describes the synthesis and SAR of these analogs.

Short synthesis of polyfunctional sp3-rich threonine-derived morpholine scaffolds

A convenient synthesis of sp³-rich complex morpholines was achieved in two steps involving a Petasis three-component coupling reaction followed by an acid- or base-mediated cyclization.

Rapid synthesis of alkylaminophenols via the Petasis borono–Mannich reaction using protonated trititanate nanotubes as robust solid–acid catalysts

The Petasis borono–Mannich reaction was applied to the synthesis of alkylaminophenols from o-hydroxybenzaldehydes, secondary amines and boronic acids in the presence of H₂Ti₃O₇ nanotubes as reusable solid–acid catalysts.

Cobalt ferrite nanoparticles: a magnetically separable and reusable catalyst for Petasis-Borono–Mannich reaction

Magnetically separable cobalt ferrite nanoparticles (CoFe₂O₄, NPS): an efficient catalyst in Petasis-Borono–Mannich (PBM) reaction between salicylaldehydes, sec. amines and aryl boronic acids.

Glycerol as an efficient medium for the petasis borono-mannich reaction

The multicomponent Petasis borono–Mannich (PBM) reaction is a useful tool for the preparation of complex molecules in a single step from boronic acids, aldehydes/ketones, and amines. Here, we describe the use of glycerol in the PBM reaction of salicylaldehydes or 2-pyridinecarbaldehyde with several boronic acids and secondary amines. From these readily available starting materials, alkylaminophenols, 2-substituted pyridines, and 2H-chromenes were prepared in reasonable to good yields. Glycerol was compared with other solvents, and in some cases, it provided the reaction product in higher yield. Crude glycerol, as generated by the biodiesel industry, was evaluated and found to be a suitable solvent for the PBM reaction, successfully expanding the potential use of this industry by-product. Based on density functional theory (DFT) calculations and the obtained experimental results, the involvement of glycerol-derived boronic esters in the reaction mechanism is suggested to be competitive with the free boronic acid pathway. Similar Gibbs free energies for the aryl migration from the boronate species to the iminium were determined for both mechanisms.

A simple and efficient synthesis of fused morpholine pyrrolidines/piperdines with potential insecticidal activities

A simple and efficient synthesis of fused morpholine pyrrolidine/piperdine core structures was accomplished via a Petasis-borono Mannich reaction of cyclic amino alcohols, glyoxal and arylboronic acids with moderate to good yields. The bioassay data showed that the synthesized compounds displayed selective insecticidal activities against armyworm and root-knot nematode.

A clear-cut example of selective Bpin-Bdan activation and precise Bdan transfer on boron conjugate addition

Activating the non-symmetrical Bpin-Bdan diboron reagent with alkoxide leads to the formation of two possible adducts: MeO(-) →Bpin-Bdan or MeO(-) →Bdan-Bpin. Experimental and theoretical investigation confirms that the MeO(-) →Bpin interaction is preferred and thus selective formation of a C-Bdan bond upon reaction with an activated C=C bond.

Build/couple/pair strategy combining the Petasis 3-component reaction with Ru-catalyzed ring-closing metathesis and isomerization

A "build/couple/pair" pathway for the systematic synthesis of structurally diverse small molecules is presented. The Petasis 3-component reaction was used to synthesize anti-amino alcohols displaying pairwise reactive combinations of alkene moieties. Upon treatment with a ruthenium alkylidene-catalyst, these dienes selectively underwent ring-closing metathesis reactions to form 5- and 7-membered heterocycles and cyclic aminals via a tandem isomerization/N-alkyliminium cyclization sequence.

Asymmetric synthesis, crystal structure, and antidepressant activity of 2-aryl-3-alkyl-5-methyl-2-morpholinol hydrochlorides

2-Aryl-3-alkyl-5-methyl-2-morpholinols were synthesized from the reactions of chiral 2-aminopropan-1-ol with 2-bromo-1-phenylpropan-1-one, 2-bromo-1-(3-chlorophenyl)propan-1-one, 1-(4-(benzyloxy)phenyl)-2-bromopropan-1-one, 2-bromo-1-(6-methoxy- naphthalen-2-yl)propan-1-one, and 1-(4-(benzyloxy)phenyl)pentan-1-one in N-methyl-2-pyrrolidone (NMP), respectively. The 2-aryl-3-alkyl-5-methyl-2-morpholinols were reacted with hydrogen chloride to give the hydrochloride salts with yields of 56%–77%. The structures of the products were proven by means of their 1H NMR, IR, and MS spectroscopic data. The stereochemical properties of representative products were established unambiguously by the X-ray single crystal analysis. The antidepressant activities of the title compounds were assayed by the mouse forced swimming test (FST). The FST results confirm the antidepressant properties of our products.Key words: morpholinol hydrochloride, hemiacetal, chiral synthesis, X-ray diffraction, absolute configuration, antidepressant activity.