New type phosphorous amides derived from protected monosaccharides

Three synthetic routes to hydrogen phosphoramidites derived from protected hydrocarbons containing one free secondary hydroxy group are explored: phosphorylation with (diethylamido)phosphorous dichloride, acidolysis of tetraalkyldiamides derived from sugars, and phosphorylation with phosphorous tetraalkyldiamides. The last route was found to be preferred. Some properties of the prepared dialkylamidoglycophosphites were studied: stability, phosphorylating activity, and behavior in oxidation reactions.     

Reaction of oxochloroalkenes with phosphorous acid esters

Conclusions 2-Qxo-3-methyl-5-chloro-3-hexene and trans-2-oxo-5-chloro-3-heptene, adequate low-molecular-weight models of labile carbonylallyl groups in poly(vinyl chloride) macromolecules, were synthesized. Tributyl phosphite reacts with the model compounds at the oxovinylene fragment via a step of formation of intermediate phosphorane structures, which are converted to stable ketophosphonates during heating.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1106–1108, May, 1985.     

Linear and cyclic aminomethanephosphonic acid esters derived from benzaldehyde derivatives, 3‐aminopropanol,and diethyl phosphite

A series of four diethyl {[(3‐hydroxy‐ propyl)amino](aryl)methyl}phosphonates have been prepared and characterized. In one case, the phosphonate was transformed to a seven‐membered 1,4,2‐ oxazaphosphepane heterocycle through a one‐pot intramolecular esterification. The analogous reaction with formaldehyde gave the six‐membered diethyl (1,3‐oxazinan‐3‐ylmethyl)phosphonate, which could be transformed in a posterior reaction to the corresponding aminomethanephosphonic acid. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:75–80, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20178     

Thiosemicarbazones derived from vanillin and vanillal esters

A new method for preparing vanillin and vanillal esters is developed.     

New bicyclic organylboronic esters derived from iminodiacetic acids

The reactions of phenylboronic acid or dinethylthexyboronic ester with iminodiacetic- or N-methyliminodiacetic acids lead to high yield to the air-stable bicyclic esters (N-B)phenyl[iminodiacete-O,N]borane (1), (N-B)phenyl[N-methyliminodiacetate-O,N]borane (2), (N-B)thexy[iminodiacetate[O,N]borane (3) and (N-B)thexyl[N-methyliminodiacetate-O,N]borane (4). These are shown by ¹H, ¹¹B and ¹³C NMR spectroscopy to have rigid bicyclic structures of strong intramolecular N-B coordination.     

Zn-Zr-Al oxides derived from hydrotalcite precursors for ethanol conversion to diethyl carbonate

Ethanol conversion to high-value-added products has attracted considerable attention in both academic research and industrial fields. In this study, we synthesized a series of tunable acid–base bifunctional Zn-Zr-Al metal oxides (represented as Zn₂Zr_xAl-MMO) in light of the structural topotactic transformation of Zn₂Zr_xAl-hydrotalcite precursors (Zn₂Zr_xAl-LDH). The resulting Zn₂Zr_xAl-MMO catalysts were employed in the conversion of ethanol to diethyl carbonate. The Zr⁴⁺ ion content of the LDH precursor plays a key role in modulating the acid-base properties and determining catalytic performance: the Zn₂Zr_0.1Al-MMO sample exhibits the optimal catalytic behavior with a diethyl carbonate (DEC) yield of 42.1%, which is the highest reported for metal oxide catalysts. Structure-property correlation investigations revealed that the synergic catalysis between medium-strong basic sites and weak acid sites plays a predominant role in the catalytic behavior. Furthermore, in situ Fourier transform infrared measurements showed that the weak acidic site promotes activation adsorption of the reactant (urea) and the intermediate product (ethyl carbamate), while the medium-strong basic site accelerates ethanol activation. Moreover, the Zn₂Zr_0.1Al-MMO catalyst has the advantages of cost effectiveness, good stability, and reusability. Therefore, the acid-base bifunctional catalysts developed in this work can be employed as promising candidates in acid-base catalytic reactions such as ethanol conversion.     

EPR-investigations of radicals derived from diethyl iodomethylphosphonate in solid and liquid state

A selective homolysis of the C I bond in diethyl iodomethylphosphonate to give the diethoxyphosphorylmethyl radical (EtO)₂P(O)CH₂· was observed in EPR spectra upon γ-irradiation and UV–vis photolysis. Analysis of stability of this radical was also investigated to show disappearance of EPR signals above 170–190 K. An attempt to observe this radical during the reaction with AIBN as an initiator failed. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:127–130, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10225     

New phenylboronic esters derived from inositol [1]

We have prepared two new tetracyclic phenylboronic esters 4 and 5 derived from myo-inositol and from 1,2-O-isopropylidene-myo-inositol, respectively. The structures of these compounds were established from NMR and IR spectra, elemental analyses, and an X-ray diffraction study in the case of 4 . Compound 4 is a tetracyclic derivative of the less stable conformer of inositol (five axial hydroxy groups and one equatorial) with two dioxaboroline rings at opposite faces of the six-membered ring, one formed between the boron atom and the axial hydroxyl groups at C-3 and C-5 and the other between the boron atom and the hydroxyl groups at C-4 and C-6, and a dioxaborolidine ring bridging C-1 and C-2 at axial and equatorial positions. A similar structure was found for 5 with the difference that bridging C-1 and C-2 there is a dioxolane ring. The boron atoms are planar with their attached atoms, stabilized by retrocoordination between the boron and oxygen and carbon atoms, respectively. The two phenyl rings that are in the same face of the molecule are essentially parallel, with a dihedral angle between planes of 28.26 ± 0.79°.     

Synthesis and mesomorphic properties of esters derived from alkanediols

New alkane-α,ω-diyl esters, propane-1,3-diyl and butane-1,4-diyl bis[4-(4-alkoxybenzoyloxy)-3-bromobenzoates], were synthesized and were found to form nematic mesophase. The effects of the lateral substituent and the length of the central and terminal hydrocarbon chains on the mesomorphic properties of butane-1,4-diyl bis[4-(4-alkoxybenzoyloxy)-3-bromobenzoates] were studied. Structural factors responsible for mesogenic properties of these compounds were determined by conformation analysis.     

Direct formation of esters and amides from carboxylic acids using diethyl chlorophosphate in pyridine

An efficient method involving pyridine activation of the carboxylate-phosphate anhydride pathway is described resulting in a direct synthesis of esters from carboxylic acids and alcohols, as well as in the formation of useful amide and peptide derivatives. The reaction proceeds with retention of configuration with both chiral secondary alcohols and α-amino acid derivatives. Ester and amide products can be isolated directly in high yield due to the water soluble nature of the side products.     

Penta- and tetracoordinated phosphorous in reactions of biacetyl with diethylacetylphosphite and diethyl chlorophosphite

Conclusions Diethylacetyl phosphite and diethyl chlorophosphite react with biacetyl, intermediately forming, as do other derivatives of phosphorous acid, 1,3,2-dioxaphospholenes with a pentacoordinated phosphorous atom; the latter are rapidly transformed to noncyclic or cyclic derivatives of tetracoordinated phosphorous.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2609–2611, November, 1968.Deceased.