Phosphonic Acids. IV.¹ Preparation and Reactions of β-Ketophosphonate and Enol Phosphate Esters²

Novel Hantzsch 1,4-dihydropyridines to study the structure-function relationships of calcium channels and photoinduced relaxation

“…The 1,4dihydropyridines [1-3] [Dagnino et al, 1986] and [4] [Vo et al, 1995] were prepared using modifications of previously reported procedures. Diethyl β-ketopropylphosphonate [23] [Jacobson et al, 1957] and nitroacetone [25] [Hurd and Nilson, 1955] [24], and all other reagents used were purchased from the Aldrich Chemical (Milwaukee, WI).…”

Dialkyl 1-Alkynylphosphonates: a Range of Promising Reagents

“…Scheme 11 The preparation of 1-alkynylphosphonates 3 by an appropriate β-elimination procedure was first recorded in 1957, when it was reported that the action of sodium ethoxide on diethyl 3-diethylphosphonoisoprenyl phosphate 22 in refluxing EtOH led to diethyl 1-propynylphosphonate 18 (R ϭ Et) in 69% yield (Scheme 12). [1,70] The experimental conditions are crucial, and it has been shown that successful elimination of phosphate takes place to the exclusion of the ethanolysis reaction only at elevated temperature. At room temperature, the enol phosphate 22 was reported to undergo competing ethanolysis to triethyl phosphate and diethyl 2-oxopropylphosphonate.…”

“…Diethyl 1-propynylphosphonate, the first 1-alkynylphosphonate, was described in 1957 [1] and the syntheses forming the basis of modern alkynylphosphonate chemistry were elaborated in the 1960's. The methodologies developed during this period for the synthesis of 1alkynylphosphonates used synthetic concepts which were new to phosphorus chemistry, such as "charge affinity inversion" and "positive halogen abstraction".…”

The Usefulness of Phosphorus Compounds in Alkyne Synthesis

“…Diethyl prop-1-ynylphosphonate (102) was obtained in 69% yield by the action of sodium ethoxide in refluxing ethanol on 2-(diethoxyphosphoryl)-1-methylvinylphosphate (101) (Scheme 46). [303][304][305] This transformation into terminal acetylene was achieved with conservation of the carbon chain. However, owing to the constraints introduced by the structural requirement, and the difficulties frequently encountered in the choice of the base and elimination condi-tions, for a long period of time this method has not been developed.…”