Reactions of 2-Alkoxy-4-oxo-5,6-benzo- 1,3,2-dioxaphosphorinanes with Imines. Synthesis and Steric Structure of 6,7-Benzo-1,4,2-oxazaphosphepine Derivatives

2-Alkoxy-4-oxo-5,6-benzo-1,3,2-dioxaphosphorinanes containing an electron-withdrawing fluorinated exocyclic substituent at the P atom react with aromatic aldimines to give 6,7-benzo-1,4,2-oxaza- phosphepines with a high regio- and stereoselectivity. The major diastereomers were isolated, and their configuration was determined by single crystal X-ray diffraction.     

Reaction of 4-Oxo-5,6-benzo-1,3,2-dioxaphosphinin-2-yl Isocyanate with Dialkyl Arylcarbonylphosphonates

Russian Journal of General Chemistry -     

Reaction of 5,6-Benzo-1,3,2-dioxathiepane 2-Oxide with Acetonitrile

Russian Journal of General Chemistry -     

Synthesis and Spatial Structure of 2,5-Dioxo-4-Dialkoxy-Phosphoryl-4-Aryl-6,7-Benzo-1,3,2-Dioxaphosphepines

Abstract

Phosphorus (111) containing dcrivatives of salicylic acid easily react with carbonyl compounds with formation of cycloexpansion products - 1,3,2- or 1,4,2-dioxaphosphepines. For the first time we have shown that dialkyl-l-oxólkylphosphonates react with 2-R-4-oxo-5,5-benzo-1,3,2-dioxaphosphorinanes and yield 1,3,2-dioxaphosphepines (I) with high stereoselectivity. The configuration of the preferable diastereoisomer (IId) has been determined by X-ray analysis. The hydrolysis of compounds (IIa-c) leads to formation of 2-hydroxy-2-oxo-1,3,2-dioxaphosphepines (III). The structure of phosphepine (IIIb) in crystal is shown on the figure. The work is supported by the Leading Scientific School Foundation of Russia (grant N 96-15-97330) and the Russian Foundation for Basic Research (grant N 98-03-33266).     

Reaction of 2-Tetrafluoropropoxy-5,6-benzo-1,3,2-dioxaphosphorinan-4-one with Pyruvonitrile

The reaction of pyruvonitrile with 2-tetrafluoropropoxy-5,6-benzo-1,3,2-dioxaphosphorinan-4-one results mainly in the enlargement of the starting heteroring to form 4-cyano-4-methyl-2-tetrafluoropropoxy-6,7-benzo-1,3,2⁵-dioxaphosphepin-5-one 2-oxide as a mixture of two diastereomers (14:1) along with minor amounts of 3-cyano-3-methyl-2-tetrafluoropropoxy-6,7-benzo-1,4,2⁵-dioxaphosphepin-5-one 2-oxide.     

Quantum-Chemical Investigation of Reaction Mechanism of 2-R-4-Oxo-5,6-Benzo-1,3,2-Dioxaphosphorinanes with Chloral and Fluoral

Abstract

Reaction of 2-R-4-oxo-5,6-benzo-1,3,2-dioxaphosphorinanes I with chloral leading to formation of seven-membered heterocycles - 1,4,2-dioxaphosphepines is characterized by the high degree of stereoselectivity. We investigated the model reactions of 2-R-4-oxo-1,3,-dioxaphosphorin-5-enes with CX₃CHO by PM3 and ab initio methods in STO-3G, 3-21G, 6-31G*, MP2/6-31G* basis set and also DFT method (B3LYP).     

Sereoselective Addition of Benzaldehyde N,N-Dimethyl-Hydrazone to 2-RfO-4-Oxo-5,6-Benzo-1,3,2-Dioxaphosphorinanes. The Spatial Structure of 2-Pentafluorophenoxy-4-Dimethylamino-2,5-Dioxo-3-Phenyl-6,7-Benzo-1,4,2-Oxazaphosphepine

Abstract

[3+2]-Cycloaddition of N,N-dimethylhydrazone benzaldehyde (I) to 2-R_FO-4-oxo-5,6-benzo-l,3,2-dioxaphosphorinanes (II) yields the new heterocycle - 2-R_FO-4-Me₂N-2,5-dioxo-3-phenyl-6,7-benzo- 1,4,2-dioxaphosphepine (III) [R_F = C₆F₅, CH(CF₃)₂) with high stereoselectivity (above 94%). The reaction is likely to involve the initial interaction of nitrogen as a nucleophile with wbonyl carbon as an electrophile. The hydrolysis of (III) leads to phosphonic acid (IV) (OR_F = OH).     

Synthesis and Spatial Structure of the Derivatives of 2,5-Dioxo-3,3-Bis(Trifluoromethyl)-6,7-Benzo-1,4,2-and 2,5-Dioxo-4,4-Bis(Trifluoromethyl)-6,7-Benzo-1,3,2-Oxazaphosphepines

Abstract

Hexafluoroacetone imine easily interacts with compounds (I, R = OMe, OCH₂CF₂CHF₂, NEt₂, Ph) in two directions unlike hexafluoroacttone and gives 1,4,2-oxazaphosphepines (II) (pathway I) or 1,3,2-oxszaphosphepines (III) (pathway 2). The compound (II) (R = NEt₂) lightly hydrolyzes to yield the salt (IV). The structure of heterocycles II-IV) has been confirmed by X-ray analysis (see fig. I, II, R = OMe; fig. 2, IV). The detail structural peculiarities of the compounds am discussed.     

Molecular and crystal structure of 2-phenyl-2-oxo-5,6 -benzo-1,3,2-dioxaphosphepine

The seven-membered heterocycle in the crystal structure of 2-phenyl-2-oxo-5,6-benzo-1,3,2-dioxaphosphepine has distorted (asymmetric) twist conformation and the plane of the phenyl substituent at the phosphorus atom does not coincide with the bisector of the plane of the OPO fragment of the heterocycle and is not perpendicular to it.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 214–217, January, 1991.     

Reaction of 2-Phenyl-1,3,2-benzodioxaphosphinan-4-one with Diethyl Benzylidenemalonate

Russian Journal of General Chemistry -     

新型3-取代(硫)色满-4-酮衍生物的合成及其结构表征

以取代或未取代(硫)色满酮和芳香醛为原料,在氢氧化钠催化下,分别采用常规溶剂法与无溶剂研磨法两种不同方式,合成一系列新型的3-取代(硫)色满-4-酮衍生物3a～3l.无溶剂研磨法具有操作简便、反应条件温和、反应时间短、对环境友好等优点.所合成的标题化合物的结构通过IR,1H NMR,13C NMR和MS进行了鉴定和表征.     

Solubility and Solution Structure of Cellulose Derivatives

Strongly interacting solvents are needed to dissolve cellulose; therefore, in the past the interpretation of the uncommon solution behavior of cellulose and its derivatives was based mainly on energetic (enthalpic) considerations, for example, hydrogen bonding. These attempts have not been very successful. The present paper demonstrates that entropic effects influence the solution behavior much stronger than hitherto supposed. In the well-known Flory–Huggins theory the driving force for dissolution of flexible chains is the configurational entropy of mixing. This large entropy is strongly reduced by the chain stiffness of the cellulose backbone and by the strictly regular primary structure of this polysaccharide. It strongly reduces the driving force for dissolution. The entropy of mixing becomes largely increased again by the attachment of long side chains and causes solubility with surprising efficiency (hairy rod principle). This effect is demonstrated with several examples. Among others, the surprising insolubility of short, regular-selectively substituted cellulose chains is explained, although long chains of the same substitution pattern are soluble. The striking behavior of cellulose ethers in water is based on the hydrophobic effect, which causes an increased order of the polymer surrounding water molecules. The induced order results in a very pronounced decrease of entropy of mixing that overcompensates the positive configurational entropy of mixing. Common rules of basic thermodynamics now predict phase separation on heating, contrary to the Flory–Huggins theory, which can only predict phase separation on cooling.