Ana M. Ochoa de Retana

A simple synthesis of 3-phosphonyl-4-aminoquinolines from β-enaminophosphonates

Abstract An easy and efficient synthesis of 4-aminoquinolines substituted with a phosphorylated group or a phosphine oxide group in the 3-position is described. The key step is a regioselective addition of lithiated β-enamino phosphonates to isocyanates to give functionalized amides. Subsequent cyclization of these compounds with triphenylphosphine and hexachloroethane in the presence of triethylamine afforded substituted 4-aminoquinolines. The deprotection of N -PMP substituted 4-amino-quinolines with CAN in acetonitrile gave primary 4-aminoquinolines.

A “one pot” synthesis of polysubstituted pyridines from metallated alkylphosphonates, nitriles and α,β-unsaturated ketones

Abstract A simple and efficient synthesis of polysubstituted pyridines is described. The key step is based on the regioselective addition of lithiated β-enaminophosphonates 5 to unsaturated carbonyl compounds 3 . Pyridines 1 can also be obtained in “one pot” reaction from phosphonates 6 when these compounds are metallated followed by addition of nitriles and unsaturated carbonyl compounds.

A regioselective synthesis of 5-pyrazolones and pyrazoles from phosphazenes derived from hydrazines and acetylenic esters

Abstract Efficient and regioselective syntheses of 1-phenyl-5-pyrazolones substituted with a phosphoranylidene group in the 3-position and of 3-alkoxycarbonyl-5-methoxy-1-phenyl pyrazoles are described. The key step is the formation of functionalized hydrazones by [2+2] cycloaddition reaction of phosphazenes derived from hydrazines with acetylenic esters. Subsequent cyclization of these compounds with butyl lithium affords substituted 5-pyrazolones, while their heating with acetonitrile leads to the formation of 3-alkoxycarbonyl-5-methoxy-1-phenyl pyrazoles in a regioselective fashion.

Synthesis of diethyl 1,2,3-triazolealkyl-phosphonates through 1,3-dipolar cycloaddition of azides with acetylenes

4,5-Disubstituted 1-(diethoxyphosphorylmethyl)-1,2,3-triazoles were prepared through thermal 1,3-dipolar cycloaddition of diethyl azidoalkylphosphonates with alkynes

Synthesis of Fluoroalkylated β-Aminophosphonates and Pyridines from Primary β-Enaminophosphonates

A simple and efficient stereoselective synthesis of fluorine containing beta-aminophosphonates by reduction of beta-enaminophosphonates is described. Reduction with sodium cyanborohydride in the presence of zinc chloride and the catalytic hydrogenation of beta-enaminophosphonates gives beta-aminophosphonates. beta-Enaminophosphonates are also used as intermediates for the regioselective synthesis of fluoroalkyl-substituted pyridines.

Easy and efficient synthesis of enantiomerically enriched 2H-azirines derived from phosphonates†

Abstract An efficient synthesis of 2 H -azirines substituted with a phosphonate group is described. The key step is an alkaloid-mediated Neber reaction of β-ketoxime tosylates. Reduction of 2 H -azirines with sodium borohydride in ethanol gives 2-phosphorylated cis -aziridines.

Selective synthesis of substituted pyrrole-2-phosphine oxides and -phosphonates from 2H-azirines and enolates from acetyl acetates and malonates.

A simple and efficient selective synthesis of 1H-pyrrole-2-phosphine oxides 3 and -phosphonates 7 by addition of enolates derived from acetyl acetates to 2H-azirinylphosphine oxide 1 and -phosphonate 6 is reported. Nucleophilic addition of enolates derived from diethyl malonate to 2H-azirines 1 and 6 led to the formation of functionalized 2-hydroxy-1H-pyrrole-5-phosphine oxide 9 and -phosphonate 10, while vinylogous α-aminoalkylphosphine oxides 14 and -phosphonate 15 may be obtained from azirines and the enolate derived from diethyl 2-phenylmalonate. Ring closure of vinylogous derivatives 14 and 15 in the presence of base led to the formation of 1,5-dihydro-3-pyrrolin-2-ones containing a phosphine oxide 17 or a phosphonate group 18.

A simple and efficient strategy for the preparation of 5-phosphorylated imidazol-2-ones from primary β-enaminophosphonates

Abstract An easy and efficient synthesis of imidazol-2-ones 5 substituted with a phosphonate group in the 5-position is described. The key step is a heterocyclization of functionalized enamines 3. These compounds 3 are formed by addition of primary β-enaminophosphonates 1 to diethyl azodicarboxylate 2.

An easy strategy for the synthesis of 5-phosphorylated pyrimidin-2,4-diones from β-phosphine oxide and phosphonate enamines

Abstract An easy and efficient synthesis of pyrimidin-2,4-diones substituted with a phosphine oxide or phosphonate group in the 5-position is described. The key step is the cyclization of functionalized amides, with ethyl chloroformate in the presence of base. In the same way, functionalized thioamides afforded substituted 5-phosphorylated 2-oxo-pyrimidin-4-thiones.

A new and efficient strategy for the preparation of 1,5,2-diazaphosphorines from primary β-enaminophosphonates

Abstract A new and efficient synthesis of 1,5,2-diazaphosphorines is described. The key step is a base-induced heterocyclization of functionalized urea compounds. These compounds are formed by addition of primary β-enaminophosphonates to isocyanates.