Preparation and Properties of Diethyl Acetoxyalkylphosphonates

McConnell, Richard L.; Coover, H. W.

doi:10.1021/ja01565a054

Cited by 29 publications

(15 citation statements)

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“…However, the reaction between 1 and 12 proceeded only when a catalytic amount of benzoyl peroxide (13) was present in the medium [15,16] to yield the respective amido-phosphates 14a -c along with the known [14] phthaloyl-DL-α-alanylamide (15) (Scheme 3). The reaction products 14a -c were obtained as colorless crystals in ∼ 62 % yield.…”

Section: Reactions Of 1 With Dialkyl Hydrogenphosphonates 12a -Cmentioning

confidence: 99%

“…Addition of an excess of tris(dimethylamino)phosphine (16) in dry tetrahydrofuran to the carbonyl azide 1 in dry THF at 20 • C led to the precipitation of the triazenylidene-phosphorane 17 (88 % yield). A 31 P NMR signal was observed at δ = 40.3 ppm.…”

Section: Reaction Of 1 With Tris(dimethylamino)phosphine (16)mentioning

confidence: 99%

“…In our continuing development of phosphono-substituted phthalimides for application purposes, we now apply trivalent and pentavalent phosphorus reagents to 2-(1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)propionylazide (1, also known as N-phthaloyl-alanylazide). Trialkyl phosphites 2a -c, dialkyl hydrogenphosphonates 12a -c and tris(dimethylamino)phosphine (16) were the applied phosphorus(III) reagents whereas triphenylalkylidenephosphoranes 18 and 20a, b were the phosphorus(V) reagents. The reactions studied and the products obtained are depicted in Schemes 1 -6.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Antimicrobial N-Phthaloyl-alanyl-derived Amidophosphates and Triazoles

Abdou

Ganoub

Sabry

2009

Zeitschrift Für Naturforschung B

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Dedicated to Professor Richard Neidlein on the occasion of his 77 th birthday N-Phthaloyl-alanylazide reacts smoothly with trialkyl phosphites producing the corresponding α-aminophosphates. With dialkyl hydrogenphosphonates in the presence of benzoyl peroxide, amidophosphates were the isolated products whereas the oxoaziridin-1-yl-phosphonic diamide was preferentially provided from the reaction of the azide with tris(dimethylamino)phosphine. The azide was also allowed to react with α-keto-, α-ethoxycarbonyl-and α-cyanomethylenetriphenylphosphorane to give the corresponding linear disubstituted 1,2,3-triazoles. Screening results of antibiotic potency for the products were discussed in terms of structure-activity relationship (SAR), and an attempt was made to define the structural features for lead compounds.

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Section: Reactions Of 1 With Dialkyl Hydrogenphosphonates 12a -Cmentioning

confidence: 99%

Section: Reaction Of 1 With Tris(dimethylamino)phosphine (16)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synthesis of Antimicrobial N-Phthaloyl-alanyl-derived Amidophosphates and Triazoles

Abdou

Ganoub

Sabry

2009

Zeitschrift Für Naturforschung B

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“…hydroxyphosphonates 4 with ketene catalyzed by BF 3 •Et 2 O 5 or H 2 SO 4 . 6 These protocols suffer from usually low yields 5 , requiring rather high temperatures (70-80 °C) and long reaction times (10-15 h). 6 Acetylation of a-hydroxyphosphonates with Ac 2 O or AcCl in the presence of Et 3 N or pyridine has been conducted at room temperature in 1-18 hours resulting in low to excellent yields.…”

Section: A-mentioning

confidence: 99%

Copper Triflate as a Useful Catalyst for the High-Yielding Preparation of α-Acetyloxyphosphonates under Solvent-Free Conditions

Firouzabadi¹,

Iranpoor²,

Sobhani³

et al. 2004

Synthesis

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A high-yielding and convenient procedure for the efficient conversion of a-hydroxyphosphonates to a-acetyloxyphosphonates using acetic anhydride in the presence of catalytic amounts of copper triflate is described.a-Acetyloxyphosphonates are considered as important and valuable phosphorus compounds for the synthesis of optically active a-hydroxyphosphonates. Enzymatic systems have been introduced for the enantioselective hydrolysis of racemic a-acetyloxyphosphonates. 1 Chiral and nonracemic a-hydroxyphosphonates are useful precursors for a variety of a-substituted phosphonates especially for a-aminophosphonic acids which have received considerable attention in medical, bioorganic and organic chemistry owing to their potential activities as analogues of aamino acids. 1a,2Literature survey indicates that a practical and high yielding method for the synthesis of pure a-acetyloxyphosphonates is rare. The reactions of aldehydes and ketones with acyl phosphites is reported for the preparation of a-acetyloxyphosphonates at 120 °C to produce the desired products in low yields. 3 The other reported procedures for this purpose include direct acetylation of ahydroxyphosphonates 4 with ketene catalyzed by BF 3 ·Et 2 O 5 or H 2 SO 4 . 6 These protocols suffer from usually low yields 5 , requiring rather high temperatures (70-80 °C) and long reaction times (10-15 h). 6 Acetylation of a-hydroxyphosphonates with Ac 2 O or AcCl in the presence of Et 3 N or pyridine has been conducted at room temperature in 1-18 hours resulting in low to excellent yields. 1b,1c,7 In the other reported procedure, AcCl has been used for direct acetylation of a-trimethylsilyloxyphosphonates at a rather high temperature (120 °C) to produce a-acetyloxyphosphonates in moderate yields (55-70%). 8 In this article we present a new procedure in which a mild Lewis acid, copper triflate [Cu(OTf) 2 ] 9 has been used for the first time for direct acetylation of a-hydroxyphosphonates with Ac 2 O at room temperature in the absence of solvent in excellent yields with short reaction times. Reactions of diethyl a-hydroxyphosphonates have been under investigation in our laboratory in recent years. 10 Along this line, recently we have introduced [Cu(OTf) 2 ] as a mild and efficient catalyst for the silylation of a-hydroxyphosphonates with HMDS. 10d A recent report on the acetylation of traditional hydroxy functional groups with Ac 2 O catalyzed by Cu(OTf) 2 11 prompted us to apply this Lewis acid catalyst for direct acetylation of diethyl a-hydroxyphosphonates. We have studied the reactions of various diethyl a-hydroxyphosphonates 1a-o in the presence of Ac 2 O catalyzed by 0.013-0.08 equivalents of Cu(OTf) 2 in the absence of solvent at room temperature (Scheme 1 and Table 1). Scheme 1As shown in Table 1, various types of diethyl a-hydroxy(arylmethyl)phosphonates 1a-k were cleanly converted into their corresponding diethyl aacetyloxyphosphonates 2a-k in excellent yields (92-98%). Diethyl a-hydroxy-2-naphthyl-, 3-pyridyl-, alkyland aryl-b,g-unsaturated phosphonates ...

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“…On the other hand, compounds of the ϾP(O)H structure can act as proton [19,20] or hydrogen [21,22] sources, depending on the structure and reaction conditions. Recently, we have been able to demonstrate that the anions of the ϾP-O ‫מ‬ type undergo a reaction with ␣-bromocarboxylates as well as with phosphonates yielding debrominated products [23][24][25].…”

Section: Introductionmentioning

confidence: 99%