The Chemistry of Organo Halogenic Molecules. 155. The Role of Reagent Structure in Halogenation of 9-Substituted Phenanthrenes

9-Substituted phenanthrenes were used as target molecules in investigations of the effect of the reagent structure and reaction conditions on halogenation with bromine (1), CsSO4F (2) and F-TEDA (1-chloromethyl-4-fluoro-1,4-diazoniabicycloe[2,2,2]octane bis(tetra- fluoroborate), (3). 9-Methoxyphenanthrene (4) was converted to 9- bromo-10-methoxyphenanthrene (6a) and 9-bromo-10-hydroxy- phenanthrene (7a), while the amount of dealkylation depended on the solvent and was more pronounced in methanol than in acetonitrile, but no adduct was observed. Addition reaction became a major process in fluorination with CsS04F (2) in methanol and 88% of 9-fluoro-10,10-dimethoxy-9,10-dihydrophenanthrene (8b) was formed, while dealkylation occurred in acetonitrile. The course of fluorination of 9-methoxyphenanthrene with F-TEDA (3) could be completely manipulated by the choice of solvent and 9,9-difluoro- 10-oxo-9,10-dihydrophenanthrene (9b) was formed in acetonitrile, 9-fluoro-10-methoxyphenanthrene (6b) in trifluoroacetic acid and 9-fluoro-10,10-dimethoxy-9,10-dihydrophenanthrene (8b) in methanol. Bromination of 9-hydroxyphenanthrene (5) in acetonitrile resulted only in the substitution process, while 9-fluoro-10-hydroxyphenanthrene (7b) formed in the reaction with CsSO4F and F-TEDA was more reactive than the starting hydroxy derivative and, using a 2 molar ratio of F-TEDA, only 9,9-difluoro-10-oxo- 9,10-dihydrophenanthrene (9b) was formed

Interspecific crosses involving Rf3 gene carriers as potential sources of R lines for D2 type cytoplasm based hybrid wheat system

The exploitation of heterosis, which is associated with the development of hybrid wheat varieties, has a great potential for increasing global wheat grain yields. Nevertheless, common wheat hybrids now account for less than 1% of global wheat production. In practice, two general approaches in hybrid wheat seeds production are being used. The first is based on the application of a chemical hybridizing agent, while the second is based on the use of cytoplasmic-genetic male sterility derived from Triticum timopheevii Zhuk. (G type cytoplasm). In this study, we present the development of R (restorer) lines for an alternative hybrid wheat system based on the cytoplasm of Aegilops crassa Boiss. (D2 type cytoplasm). Considering the cytoplasm types, it was found that different types of experimental F1 crosses required different sources of fertility restorer genes. CMS materials with T. timopheevii cytoplasm achieved the highest productivity in combination with Rf3 gene carriers. On the other hand, CMS materials with D2 cytoplasm in combination with interspecific crosses of synthetic hexaploid wheat accessions and SBEII mutants led to highly heterotic F1 hybrids

Oxidative cleavage of C–C double bond in cinnamic acids with hydrogen peroxide catalysed by vanadium(V) oxide

We have developed a cheap, green, mild and environmentally friendly method for the selective cleavage of carbon–carbon double bonds with a 30% aqueous solution of hydrogen peroxide as the oxidant and vanadium(V) oxide as the catalyst. The selectivity of the oxidative cleavage of cinnamic acid derivatives 1 depends on the substituents and the solvent used (DME – MeOCH$_2$CH$_2$OMe, TFE – 2,2,2-trifluoroethanol or MeCN). In DME, p-hydroxy derivatives were selectively converted to benzaldehyde derivatives 2, in TFE, oxidative cleavage led to the formation of benzoquinone derivatives 4, while in MeCN, cinnamic acid derivatives were selectively converted to benzoic acid derivatives 3. Ferulic acid 1a was quantitatively and selectively converted to vanillin 2a in a 91% isolated yield on a gram scale. Dimeric difurandione 1a’ was isolated as an intermediate, which was confirmed by in situ ATR-IR spectroscopy, while the formation of diols or epoxides was not observed. The analogous styrene derivative, 4-vinylguaiacol 1e was also selectively converted to either vanillin 2a or 2-methoxyquinone 4a in a high yield. The green metric for the conversion of ferulic acid to vanillin by different methods was calculated and compared to our method, and showed that our method has better environmental parameters

Conversion of Aryl Iodides into Aryliodine(III) Dichlorides by an Oxidative Halogenation Strategy Using 30% Aqueous Hydrogen Peroxide in Fluorinated Alcohol

Oxidative chlorination with HCl/H2O2 in 1,1,1-trifluoroethanol was used to transform aryl iodides into aryliodine(III) dihalides. In this instance 1,1,1-trifluoroethanol is not only the reaction medium, but is also an activator of hydrogen peroxide for the oxidation of hydrochloric acid to molecular chlorine. Aryliodine(III) dichlorides were formed in 72–91% isolated yields in the reaction of aryl iodides with 30% aqueous hydrogen peroxide and hydrochloric acid at ambient temperature. A study of the effect that substituents on the aromatic ring have on the formation and stability of aryliodine(III) dichlorides shows that the transformation is easier to achieve in the presence of the electron-donating groups (i.e. methoxy), but in this case the products rapidly decompose under the reported reaction conditions to form chlorinated arenes. The results suggest that oxidation of hydrogen chloride with hydrogen peroxide is the initial reaction step, while direct oxidation of aryl iodide with hydrogen peroxide is less likely to occur

The effect of fluorine atom on the synthesis and composition of gametocidal ethyl oxanilates

Three derivatives of ethyl oxanilate were synthesized in order to test their application as gametocides on the hermaphrodite plants like common wheat (Triticum aestivum L.). A substituent at para position (F, Br, CN) of aniline defined its reactivity towards diethyl oxalate 2. Classical reaction in toluene was not selective and amidation occurred also at the second carbonyl groups of 2. Alternative synthesis under solvent-free conditions with application of low pressure for removal of EtOH provided selectively with ethyl oxanilate 3a and 3b. 4-Cyanoaniline did not react selectively and the corresponding ethyl oxanilate 3c was prepared from mono acid chloride of oxalic acid. Fluoro derivative 3a was found to be the only one that gives stable aqueous suspension for its application as chemical hybridizing agent for common wheat, while bromo- 3b and cyano- 3c analogues were not soluble enough and suspension was stable for less than 2 hours. Fluoro derivative had shown the best induction of male sterility, while in comparison with standard chemical hybridizing agent they were substantially less toxic for plant

Combining ability and heterosis effect in hexaploid wheat group

The main goal of hybrid wheat breeding is the identification of parents with high specific combining ability for grain yield and other agronomic traits. This kind of data facilitate the development of hybrid combinations with high level of heterosis in first filial generation (F1 generation). The use of species from the hexaploid wheat group (e.g. Triticum spelta L. Triticum compactum HOST...) is representing an opportunity for the increase of heterosis level in the germplasm of common wheat (Triticum aestivum L.). The study of combining ability and heterosis effect in hexaploid wheat group was carried out using crosses between thirteen inbred lines of common wheat (6 lines x 7 testers) and inter-species crosses (T. aestivum L. × T. spelta L., T. aestivum L. × T. compactum HOST, T. aestivum L. × T. sphaerococcum PERCIV., T. aestivum L. × T. macha DEKAPR. et MENABDE, T. aestivum L. × T. petropavlovskyi UDACZ. et MIGUSCH, T. aestivum L. × T. vavilovii (THUM.) JAKUBZ.). The 42 common wheat F1 hybrids were tested during two seasons (2010/11 and 2011/12) on the Selection center Ptuj. The experiment was carried out in a randomized block design with four replications. The 43 interspecies F1 hybrids were tested on the same location in the season 2011/12 and the experiment was designed as an randomized block with three replications. The results were analyzed using statistical package AGROBASE generation II and STATGRAPHICS Centurion XVI. The analysis of variance was significant for both, GCA and SCA variances (P < 0,01). Generally, SCA variances were lower than GCA variances. We could state, that the improvement of heterosis level in the common wheat germplasm through the use of relatives with the same genome (genome BAD) is possible. As an example we can point out the interspecies F1 hybrid between common wheat variety Garcia and an accession of the Triticum sphaerococcum PERCIV. species (accession number 01C0201227)

Biodegradable hydrogels - materials of the future

Hidrogeli spadajo v skupino tridimenzionalnih polimernih materialov, ki lahko absorbirajo in sproščajo velike količine vode na reverzibilen način kot odziv na okoljske dražljaje. Imajo širok potencial uporabe v prehrani, biomaterialih, kmetijstvu itd. Glede na njihov izvor jih delimo na hidrogele narejene iz naravnih polimerov in na hidrogele, pripravljene iz sintetičnih polimerov. Med najpomembnejšimi naravnimi hidrogeli, ki se danes precej pogosto uporabljajo, so hidrogeli na osnovi celuloze, ki jih sintetiziramo bodisi iz čiste celuloze, celuloznih kompozitov oziroma celuloznih hibridnih hidrogelov. Med najpogosteje uporabljenimi derivati celuloze za sintezo takih hidrogelov so karboksimetil celuloza, hidroksietil celuloza ali hidroksipropil celuloza. Po navadi so zamreženi z dikarboksilnimi kislinami (npr. citronsko kislino). Sinteza hidrogelov iz nativne celuloze je veliko bolj zahtevna predvsem zaradi slabe topnosti celuloznih vlaken v običajnih topilih. Večina uporabljenih karboksilnih kislin je biorazgradljiva