Regio- and Stereoselective [2+2] Photodimerization of 3-Substituted 2-Alkoxy-2-oxo-2H-1,2-benzoxaphosphorines

Abstract

Diethyl 1,2-benzoxaphosphorine-3-carboxylates 5 undergo a regio- and stereoselective [2+2] photodimerization reaction in methanol solution under the action of sunlight, giving in all cases the corresponding anti head-to-tail dimers 6 and 7. Concerning the stereogenic P atom, the photodimerization is also stereoselective, and the centrosymmetric stereoisomer 6 predominates over the non symmetric P-epimer 7.

The Use of Umbelliferone in the Synthesis of New Heterocyclic Compounds

“…Coumarin and its derivatives represent one of the most active classes of compounds, possessing a wide spectrum of biological activity [4,5,6,7]. Many of these compounds have proved to be active as antibacterial [8,9], antifungal [10], anti-inflammatory [11], anticoagulant [12], anti-HIV [13] and antitumor [14] agents.…”

Crystal Structure and Spectroscopic Properties of (2-oxo-2H-chromen-3-yl)phosphonic Acid Monoethyl Ester Trihydrate

“…On the other hand, the predicted values of ν P O , ν as PO2 , and ν s PO2 stretching vibrations differ by 15-22 cm −1 . This result can be explained Table 4 Data of the ν i and A i of the IR-bands within 1300-800 cm −1 region obtained by preliminary deconvolution and curve-fitting procedure ( Figure 5) 5 3.9395 1039.4 6 14.8168 1251.5 8 3.1047 1012.4 4 14.4514 1211.0 8 6.9970 987.3 7 12.5481 1172.5 1 12.9694 950.7 3 12.8425 1133.9 6 10.3541 917.9 5 5.81360 1101.1 6 8.16931 883.2 3 1.36457 1110.7 9 7.73644 863.9 5 .2636 by the participation of the discussed functional groups in hydrogen bond interactions in the solid-state (Table 3). Similar results are obtained for the correlation between the theoretical and experimental values also for other derivatives.…”

“…27 (2-Oxo-2H-chromen-3-yl)phosphonic acid monoethyl ester was synthesized according to the synthetic scheme reported in refs. [5][6][7][8] The hydrolysis of corresponding ethyl phosphonate to phosphonic acid derivative 1 is achieved in a suspension of 2 mmol of the corresponding ethyl ester in conc. HCl (2 mL) upon refluxing for 30 min.…”

Ethyl esters of coumarin-3-phosphonic acid and 1,2-benzoxaphosphorine-3-carboxylic acid: crystal structure, spectroscopic and theoretical elucidation

“…Derivatives with the phosphorus atom at position 2 of the c-pyrone ring are known as efficient antibacterial agents [4][5][6][7]. Our systematic investigations of derivatives of coumarin-3-phosphonic acid have been mainly concerned with these known facts [8][9][10][11][12]. In contrast to the large number of synthetic papers [8][9][10][11][12], very few reports of the optical and magnetic properties of this class of coumarin derivatives have appeared [13,14].…”

“…Our systematic investigations of derivatives of coumarin-3-phosphonic acid have been mainly concerned with these known facts [8][9][10][11][12]. In contrast to the large number of synthetic papers [8][9][10][11][12], very few reports of the optical and magnetic properties of this class of coumarin derivatives have appeared [13,14]. In our previous articles, the correlation between the structure and spectroscopic properties of coumarin-3-phosphonic acid and its esters has been elucidated [15,16].…”