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Bisphosphonates are widely used in medicine and related areas, mainly for the treatment of bone diseases, such as osteoporosis. However, their synthesis is usually performed under harsh reaction conditions. In order to overcome this limitation, the present work illustrates a new synthetic route to access the title α-aminobisphosphonate in milder reaction conditions using α-phosphorylated imines as key intermediates. [ABSTRACT FROM AUTHOR]

We report efficient synthetic methodologies for the preparation of 3-amino and 3-hydroxy 3-pyrrolin-2-ones (unsaturated γ-lactams) through a multicomponent reaction of amines, aldehydes and acetylene or pyruvate derivatives. The densely substituted γ-lactam substrates show in vitro cytotoxicity, inhibiting the growth of the carcinoma human tumor cell lines RKO (human colon epithelial carcinoma), SKOV3 (human ovarian carcinoma) and A549 (carcinomic human alveolar basal epithelial cell). In view of the possibilities for the diversity of the substituents that offer a multicomponent, synthetic methodology, an extensive structure–activity profile is presented. In addition, the bioisosteric replacement of the flat ester group by a tetrahedral phosphonate or phosphine oxide moiety in γ-lactam substrates leads to increased growth inhibition activity. Cell morphology analysis and flow cytometry assays indicate that the main pathway by which our compounds induce cytotoxicity is based on the activation of the intracellular apoptotic mechanism. [ABSTRACT FROM AUTHOR]

An efficient method for the preparation of quaternary α-aminophosphonic acid derivatives is reported. The nucleophilic addition of organometallic reagents to α-ketiminophosphonates allows the preparation of quaternary α-aminophosphonates. The diastereoselective synthesis of a quaternary α-aminophosphonate using a chiral tartaric-acid-derived phosphonate is also described. [ABSTRACT FROM AUTHOR]

A synthetic route for a phosphorylated 1,3-oxazin-6-one has been described, its reactivity towards nucleophiles and heterodienophiles has been assessed, and new α-dehydro-aminophosphonate derivatives are obtained. [ABSTRACT FROM AUTHOR]

The synthesis of α-iminophosphonates derived from ketones has been achieved by aza-Wittig reaction of P-trimethylphosphazenes with acylphosphonates. These unstable compounds can be used for the synthesis of chiral α-aminophosphonate derivatives through addition of nucleophiles to the C-N iminic double bond. Moreover, if α,β-unsaturated imines are used, regioselective Michael addition to the conjugated bond yields α-dehydroamino-phosphonic acid derivatives functionalized at the γ-position. [ABSTRACT FROM AUTHOR]

A series of α-mono- and α,α-difluoro-β-ketophosphonates were synthesized in moderate to good yields with excellent selectivities via electrophilic fluorination by Selectfluor. Subsequently, synthetic potential of the obtained α-monofluoro-β-ketophosphonates was demonstrated by their application in synthesis of α-monofluoro-β-aminophosphonates, useful building blocks in the preparation of phosphapeptides. [ABSTRACT FROM AUTHOR]

An efficient synthesis of α,β-unsaturated imines derived from α-aminophosphonates is achieved through aza-Wittig reaction of P-trimethyl phosphazenes with β,γ-unsaturated α-ketophosphonates. Selective 1,2-reduction of such 1-azadienes affords β,γ-unsaturated α-aminophosphonates, phosphoryl ated analogs of vinyiglycines, which are hydrogenated to yield saturated α-aminophosphonate derivatives. [ABSTRACT FROM AUTHOR]

A simple and efficient stereoselective synthesis of fluoroalkyl substituted aziridine-2-phosphine oxides and -phosphonates by diastereoselective addition of methoxide, imidazole, benzenethiol, and Grignard reagents to functionalized ketoxime-phosphine oxides and -phosphonates is described. Aziridines are used as intermediates for the regioselective synthesis of fluorine containing β-amino phosphine oxides and β-amino phosphonates. Amino phosphorus derivatives can also be obtained from ketoximes derived from phosphine oxides and phosphonates with sodium borohydride. [ABSTRACT FROM AUTHOR]

A simple and efficient stereoselective synthesis of aziridine-2-phosphonate-3, and -phosphine oxide 5 by diastereoselective addition of Grignard reagents to 2H-azirine phosphonate 1 and -phosphine oxide 4 is reported. Similarly, the addition of heterocyclic amines and benzenethiol to aziridines 1 and 4 yielded functionalized aziridines 10, 11, and 18. These aziridines are used as intermediates for the regioselective synthesis of β-aminophosphine oxides 6 and α-aminophosphonates 7, as well as α-aminophosphonates 8. Phenylsulfenyl-substituted α-aminophosphorus derivatives 15 and 19 are obtained directly from benzenethiol and 2H-azirine phosphonates 1 and -phosphine oxides 4. [ABSTRACT FROM AUTHOR]

Abstract: 1,2-Diaza-1,3-butadienes derived from phosphine oxides and phosphonates and with optically active substituents on N-1 and C-3 are obtained by 1,4-elimination from chlorohydrazonoalkyl-phosphine oxides and -phosphonates in the presence of bases. Michael addition (1,4-addition) of ammonia, aliphatic and aromatic amines and aminoesters to these azo-alkenes gives functionalized α-amino-phosphine oxides and -phosphonates. [Copyright &y& Elsevier]

Abstract: A simple method for the preparation of phosphorus-containing pyrimidine analogues such as 2,5-dihydro-2-ethoxy-1,5,2-diazaphosphinine 2-oxides 9, 12–15 and adducts 3, 10 is described. Dihydrophosphinines 9, 12–15 are prepared from primary enamine phosphonates and nitriles or from phosphonates and nitriles in the presence of base, while highly stable hydrogen-bonded amine-dihydro-diazaphosphinine adducts 3, 10 are obtained by the addition of amine to dihydrophosphinines 9 or by reaction of alkylphosphonates with nitriles in the presence of LDA. [Copyright &y& Elsevier]

A simple method for preparation of fluoroalkyl β-enaminophosphonates 1 from alkylphosphonates 2 and perfluoroalkyl nitriles 3 is reported. Olefination reaction of functionalized phosphates I with aldehydes gives α,β-unsaturated imines 5. Acid hydrolysis of these fluoroalkyl derivatives 5 affords α,β-unsaturated ketones 6, while their selective reduction with hydrides leads to the formation of allylamines 7, enamines 8, and saturated ketones 9 or amines 10. Selective oxidative cleavage of the carbon-carbon double bond of allylamines 7 gives fluorinated α-amino aldehydes 12, α-amino ketones 13, or α-amino acid derivatives 14. [ABSTRACT FROM AUTHOR]

A simple and efficient regioselective synthesis of 4-oxazole-phosphine oxides 11 and -phosphonates 12 from 2H-azirine-phosphine oxides 1 and -phosphonates 6 is described. The key step for the synthesis of oxazoles 11 is a base-mediated ring closure of vinylogous α-aminophosphorus compounds derived from phosphine oxides 4 and from phosphonates 8. These derivatives 4 and 8 are obtained by reaction of functionalized azirines 1 and 6 with acyl chlorides 2 and subsequent acid-catalyzed ring opening of N-acylaziridine-phosphine oxides 3 and -phosphonates 7. Regioselective thermal ring cleavage of N-acylaziridine-phosphine oxides 3 leads α-chloro-β-(N-acylamido)-phosphine oxides 13 and their treatment with bases gives 5-oxazole-phosphine oxides 16. [Copyright &y& Elsevier]

A simple and efficient method for asymmetric synthesis of 2H-azirine-2-phosphonates 6 is described. The key step is a base-mediated Neber reaction of p-toluenesulfonyloximes 4 derived from phosphonates. Triethylamine 5, alkaloids 7 and solid-phase bound achiral 8 or chiral amines 9 are used. Reduction of 2H-azirines 6 with sodium borohydride in ethanol gives cis-aziridine-phosphonates 10. Ring opening of aziridines 10 and 11 leads to the formation of enantiomerically enriched β-12 and 14 and α-aminophosphonates 13 and 15. [Copyright &y& Elsevier]

This work describes, for the first time, the synthesis of dialkyl (2-arylquinolin-8-yl)phosphonate derivatives. The preparation was carried out through a direct and simple process as a multicomponent Povarov reaction of aminophenylphosphonates, aldehydes, and styrenes and subsequent oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or, alternatively, by a cycloaddition reaction between phosphonate aldimines and acetylenes. Based on phosphonate group structural characteristics, considered as phosphorous isosteres of carboxylic heterocycles, they may present interesting biological properties related to cell proliferation. In the current report, a new series of dialkyl (2-arylquinolin-8-yl)phosphonates have been synthesized and their antiproliferative effect evaluated on different human cancer and embryonic cells, as well as on Leishmania infantum parasites, a eukaryotic protist responsible for visceral leishmaniasis. Thereby, the antitumor effect was assessed in human lung adenocarcinoma cells (A549), human ovarian carcinoma cells (SKOV3), and human embryonic kidney cells (HEK293) versus the non-cancerous lung fibroblasts cell line (MRC5). On the other hand, the antileishmanial activity was tested against both stages of L. infantum cell cycle, namely free-living promastigotes and intramacrophage amastigotes, using a primary culture of Balb/c splenocytes to calculate the selectivity index. Besides the antiproliferative and antileishmanial capacities, their behavior as topoisomerase 1B inhibitors has been evaluated as a possible mechanism of action. [ABSTRACT FROM AUTHOR]

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-lH-pyrrole-5-phosphine oxide 9 and -phosphonate 10, while vinylogous a-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 l,5-dihydro-3-pyrrolin-2-ones containing a phosphine oxide 17 or a phosphonate group 18. [ABSTRACT FROM AUTHOR]

Cyclopenta[b]-pyrrole-2-phosphine oxides 4a and -phosphonates 4b,c are generated by the addition of cyclic enolates derived from ethyl 2-oxo-cyclopentanecarboxylate 2 to phosphorated 2H-azirines 1. However, the addition of enolate derived from acyclic 2-oxo-butanoate 10 to 2H-azirine phosphine oxide 1 led to vinylogous N-acyl-a-aminoalkyl phosphine oxides 12, involving the carbonyl group and the Ca of the keto ester 10. Ring closure of vinylogous derivative 12 in the presence of base afforded pyrrole-2-phosphine oxide 11. The addition of enolates derived from indenone-carboxylate 15 to 2H-azirines 1 led to the formation of functionalized N-substituted 1H-benzo[d]azepine derivatives 17. [ABSTRACT FROM AUTHOR]

Bifunctional Cinchona alkaloid thioureas efficiently catalyze asymmetric nucleophilic addition of nitromethane to ketimines derived from α-aminophosphonic acids to afford tetrasubstituted α-amino-β-nitro-phosphonates. Catalytic hydrogenation of (S)-α-amino-β-nitro-phosphonate 2d gives enantiopure (S)-α,β-diaminophosphonate 3. [ABSTRACT FROM AUTHOR]

Addition reaction of organometallic reagents to tertiary α-iminophosphonates offers an efficient strategy for the preparation of quaternary α-aminophosphonates. [ABSTRACT FROM AUTHOR]

The functionalized polyfluorophosphorylated 1-azadienes I have been prepared by a Wittig reaction of ethyl glyoxalate and perfluorophosphorylated conjugated phosphoranes, obtained by reaction of phosphazenes and fluorinated acetylenic phosphonates. Subsequent reduction of both carbon-carbon and carbon-nitrogen double bonds of these 1-azadienes I affords the fluorine-containing β-aminophosphonates II, with the syn β-aminophosphonate being obtained as the major diastereoisomer. Base-mediated cyclocondensation of a diastereomeric mixture of aminophosphonates II leads exclusively to a new type of functionalized trans-γ-lactams III in a diastereoselective way. A computational study has also been used to explain the observed diastereoselectivity of these reactions. [ABSTRACT FROM AUTHOR]

The synthesis of highly functionalized N-hydroxypyrrole derivatives by the formal [3+2] cycloaddition reaction of enamines and nitroso alkenes derived from phosphine oxides and phosphonates is reported. Intermediate phosphorylated nitrones, whose formation can be explained by a conjugate addition of enamines to phosphorylated nitroso alkenes and formation of the five-membered heterocycles, are isolated. [ABSTRACT FROM AUTHOR]

An abstract of the article "Reaction of 2H-Azirine-Phosphine Oxides and -Phosphonates With Enolates Derived From ß-Keto Esters" by A. Velez del Burgo et al. is presented.

The catalytic hydrogenation of the phosphonate (IIIa) to afford enantiopure α,β-diaminophosphonate (IV) is also presented. [ABSTRACT FROM AUTHOR]