Hydrogenation/Regioselective C‐Acylation Reaction of Diethyl Coumarin‐3‐phosphonate With NaBH4/Acid Anhydrides: A New One‐Pot Tandem Reaction

The one‐pot tandem reaction of diethyl coumarin‐3‐phosphonate 1 with a mixture of sodium borohydride/acid anhydrides gives mainly the corresponding hydrogenation/acylation product of diethyl 3‐acyl‐2‐oxochroman‐3‐ylphosphonates 3a–d in good yields. Different experimental conditions have been examined to get the best yields of the reaction products. From this reaction the hydrogenation product of diethyl 2‐oxochroman‐3‐ylphosphonate, 2, as well as the products of the consecutive hydrogenation, diethyl 2‐hydroxychroman‐3‐ylphosphonate (4) and diethyl 3‐[2‐hydroxyphenyl]‐1‐hydroxy‐propan‐2‐ylphosphonate (5), have been isolated.     

Rheological behaviour of VPVC/RPVC Blends

Different blends of virgin pipe‐grade PVC and PVC recyclate according to their rheological behaviour, processability and mechanical properties have been investigated. Our results showed that an easy and simple way to improve processability of PVC compounds for pipes was to blend them with recycled PVC obtained from postconsumed oil bottles, which indicated very good processing behaviour. Energy and time savings up to 80% depending on the amount of the added recyclate without depressing the mechanical properties have been noticed. In addition, lower processing temperature has been achieved.     

Construction of new symmetric designs with parameters (70,24,8)

This article presents a construction of all symmetric designs with parameters (70,24,8) on which the group E₈ F₂₁ operates so that the automorphism of order 7 operates fixed-point-free. A method based on enumeration of cosets in group is used for the construction.     

Structure and spectroscopic characterization of 1- and 2-hydrazonoyl-1,2,3-triazoles

The synthesis of some 1- and 2-hydroazonoyl-1,2,3-triazoles by reaction of the corresponding 1,2,3-triazoles and nitrilimines is described and their characterization by ¹³C nmr and mass spectroscopy is provided. The structure of a 2-hydrazonoyl derivative 6b was determined by X-ray analysis.     

Substituted Esters of Coumarin-3-phosphonic Acid—Linear-Polarized IR-Spectroscopic Elucidation

Correlation between the structure and IR-spectroscopic properties of two halogen and one amino substituted esters of coumarin-3-phosphonic acid has been studied by means of linear-polarized IR-spectroscopy of oriented colloid suspensions in nematic host. The influence of the ester group on the peak positions of the IR-characteristic bands of these derivatives and in particular, on phosphorus group is investigated by a comparison with the data for corresponding coumarin-3-phosphonic acids. Theoretical quantum chemical DFT calculations (B3LYP/6-311++G??) are carried out, thus supporting the experimental assignment of the IR-bands and predicting the electronic structure of all of the compounds studied.