Reaktive E=C(p-p)π-Systeme, VI [1] Reaktionen des Phosphaalkens F3CP=CF2 mit H-aciden Verbindungen/Reactive E = C(p-p)π-Systems, VI [1] Reactions of the Phosphaalkene F3CP = CF2 with H Acidic Compounds

1986 ◽  
Vol 41 (2) ◽  
pp. 149-161 ◽  
Author(s):  
Joseph Grobe ◽  
Duc Le Van ◽  
Jürgen Nientiedt
Keyword(s):  
Double Bond ◽  
Opposite Direction ◽  
Rate Of Reaction ◽  
Ph Dependent ◽  
Acidic Compounds ◽  
New Compounds ◽  
Derivatives Of

The reactions o f the perfluorophosphaalkene F3CP = CF2 (1) with HX compounds proceed via addition to the PC double bond yielding either secondary phosphanes F3CP(H)CF2X (X = OH, OR, NR2, PMe2) or PX derivatives F3CP(X)CF2H (X = Cl, Br, SMe, SeMe, AsMe2). The rate of reaction with H2O is strongly pH-dependent, but only at pH > 13 the opposite direction of addition is observed. Similar results are obtained for the addition of alcohols, for which the presence of OR- results in two effects: (i) Reversion of the addition direction to yield F3CP(OR)CF2H; (ii) HF elimination from F3CP(H)CF2OR to give substituted phosphaalkenes. With strong bases HNR2, the addition is followed immediately by HF elimination producing the surprisingly stable phosphaalkenes F3CP = C(F)NR2 (R = Me, Et). Secondary phosphanes of the type F3CP(H)CF2X (X = OMe, OEt, PMe2) are found to be suitable precursors for the preparation of novel heterosubstituted derivatives of 1 by elimination of HF with NMe3. New compounds were characterized by NMR, MS, GC/MS and GC/IR measurements.

Reaktive E =C (p—p)π-Systeme, X Darstellung und Reaktivität von Perfluor-3-phosphapent-2-en / Reactive E = C (p-p)π-Systems, X Preparation and Reactivity of Perfluoro-3-phosphapent-2-ene

1986 ◽  
Vol 41 (8) ◽  
pp. 974-980 ◽  
Author(s):  
Joseph Grobe ◽  
Jürgen Szameitat
Keyword(s):  
Double Bond ◽  
Room Temperature ◽  
Diels Alder ◽  
Cycloaddition Reactions ◽  
Dilute Solution ◽  
Concerted Mechanism ◽  
Thermal Elimination ◽  
Acidic Compounds ◽  
New Compounds ◽  
First Time

Abstract Perfluoro-3-phosphapent-2-ene F5C2 P =C (F )CF3 (1) has been prepared for the first time by thermal elimination of trimethyltin fluoride Me3SnF from trim ethylstannyl-bis(pentafluoroethyl)- phosphane Me3SnP(C2F5) 2 at 300 °C/10−3 Torr. 1 is found to be less stable than F3CP = CF2 in dilute solution at room temperature, forming several 1,3-diphosphabutane dimers. Reactivity studies accomplished till now include (i) the dienophilicity of 1 in [2+4] cycloaddition reactions with butadiene, 2,3-dim ethylbutadiene, cyclopentadiene, 1,3-cyclohexadiene, 2-methylbutadiene, and 2-methylfuran leading by a concerted mechanism to the Diels-Alder-adducts 2-7 in about 80% yield, (ii) the addition of proton acidic compounds HX (X = OMe, Br, NMe2, NEt2) to the PC double bond affording chiral phosphanes of the type F5C2 P(X)CF(CF3)H [X = OMe (8). Br (9). NMe2 (10). NEt2 (11)]. thus proving a stronger polarity δ+P =δ−C for 1 than for F3CP = CF2. New compounds have been characterized by NMR and MS measurements.

Reaktive E = C (p—p) π -Systeme, XI. Hydrometallierungsreaktionen des Perfluor-2-phosphapropens F3CP = CF2/ Reactive E = C (p —p) π -Systems, XI. Hydrometallation Reactions of Perfluoro-2-phosphapropene F3CP = CF2

1987 ◽  
Vol 42 (8) ◽  
pp. 984-992 ◽  
Author(s):  
Joseph Grobe ◽  
Duc Le Van ◽  
Jürgen Nientiedt
Keyword(s):  
Double Bond ◽  
Spectroscopic Data ◽  
Cycloaddition Product ◽  
The Stability ◽  
New Compounds ◽  
Derivatives Of

AbstractThe reactions of F3CP = CF2 (1) with Me3GeH, Me3SnH, and (C5R5)(CO)3MH (M = Cr. Mo, W; R = H , Me) proceed via addition to the PC double bond yielding tertiary phosphanes of the type Me3M′P(CF3)CF2H[M′ = Ge (2), Sn (3)] or (C5R5)(CO)3MP(CF3)CF2H [R = H; M - Cr (6), Mo (7). W (8); R = Me; M = Mo (9), W (10)]. 2 and 3 are labile compounds, which decompose by elimination of Me3M′F , a reaction which in the case of 3 has been used to prepare the new phosphaalkene F3CP = C(H)F (5) and its [2+4]-cycloaddition product 4 with 2.3-dimethyl-1.3- butadiene. The H substituent (instead of F) in 5 and its derivatives has a surprising influence not only on the stability of the compounds but also on their spectroscopic data, as shown by com parison with 1 and derivatives of the type Me3M ′P(CF3)2 and (C5H5)(CO)3MP(CF3)2. respectively. New compounds are characterized by NMR, MS. GC/MS and IR measurements.

SOME DIRECTIONS IN THE MODIFICATION OF AZOLES

2020 ◽  
Vol 5 (443) ◽  
pp. 85-91
Author(s):  
Ibrayev M.K., ◽  
◽  
Takibayeva A.T., ◽  
Fazylov S.D., ◽  
Rakhimberlinova Zh.B., ◽  
...  
Keyword(s):  
13C Nmr Spectroscopy ◽  
Biologically Active Compounds ◽  
Biologically Active ◽  
Active Compounds ◽  
Synthesis Conditions ◽  
Alkaloid Cytisine ◽  
Azole Ring ◽  
Cyclic Compounds ◽  
New Compounds ◽  
Derivatives Of

This article presents studies on the targeted search for new derivatives of azoles, such as benzthiazole, 3,5-dimethylpyrazole, 1,3,4-oxadiazole-2-thione, 1,3,4-thiadiazole. The possibility of combining in one molecule of the azole ring with other cyclic compounds: the alkaloid cytisine, morpholine, furan and some arenes has been studied. To obtain new compounds, the reactions of bromination, acylation, and interaction with isothiocyanates were studied. Optimal synthesis conditions were studied for all reactions. It was found that the reaction of 4-bromo-3,5-dimethylpyrazole with isothiocyanates, in contrast to the previously written derivatives of anilines, takes a longer time and requires heating the reaction mixture. The combination of a pirasol fragment with halide substituents often results in an enhanced therapeutic effect. The synthesized 2-bromine-N-(6-rodanbenzo[d]thiazole-2-yl)acetamide, due to the alkylbromide group, is an important synth in the synthesis of new benzthiazole derivatives. Its derivatives combine in one molecule the rest of rhodanbenzthiazole with alkaloid cytisine and biogenic amine morpholine and are potentially biologically active compounds, since the molecule structure contains several pharmacophoric fragments: benzthiazole and alkaloid (amine) heterocycles, rhodane and urea groups. The mechanism of formation of 1,3,4-oxadiazole-2-tyons from hydrazides under action on them by carbon disulfide was studied and assumed. It was shown that dithiocarbamates in acidic medium decompose with the release of hydrogen sulfide and the formation of highly reactive isothiocyanate group. Then, intra-molecular cyclization occurs, with the formation of end products - 1,3,4-oxadiazole-2-thions. The structures of the synthesized compounds were studied by 1H and 13C NMR spectroscopy. All synthesized substances are potentially biologically active compounds, since they contain several pharmacophore fragments in their structure.

Synthesis and Antimicrobial activities of Some Polyphenol compounds by Nano ZnO-TBAB as a Heterogeneous Catalytic Media

2020 ◽  
Vol 17 ◽  
Author(s):  
Rahele Bargebid ◽  
Ali Khalafi-Nezhad ◽  
Kamiar Zomorodian ◽  
Leila Zamani ◽  
Ali Ahmadinejad ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
Antimicrobial Activities ◽  
Reusable Catalyst ◽  
Nano Zno ◽  
Antifungal Activities ◽  
Chemical Structures ◽  
Heterogeneous Catalytic ◽  
Solvent Free Conditions ◽  
New Compounds ◽  
Derivatives Of

Introduction: Mannich reaction is a typical example of a three-component condensation reaction and the chemistry of Mannich bases has been the matter of search by researchers. Here an efficient procedure for the synthesis of some new Mannich derivatives of simple phenols is described. Methods: In this procedure a microwave-assisted and solvent less condensation were done between different phenols, secondary amines and paraformaldehyde. The reactions proceed in the presence of catalytic amount of nano ZnO and tetrabutylammonium bromide (TBAB) in excellent yields. 10 new compounds were synthesized (A1-A10). Chemical structures of all new compounds were confirmed by different spectroscopic methods. We optimized the chemical reactions in different conditions. Optimization reactions were done in the presence of different mineral oxides, different amount of TBAB and also different solvents. Nano ZnO and TBAB in catalytic amounts and solvent free conditions were the best conditions. All the synthesized compounds were screened for their antimicrobial activities. Antifungal and antibacterial activities of the synthesized compounds were evaluated against some Candida, filaments fungi, gram positive and gram negative bacteria by broth micro dilution method as recommended by CLSI. Results: The result showed that compounds A2, A3 and A4 against most of the tested Candida species and compounds A5 and A7 against C. parapsilosis and C. tropicalis, exhibited considerable antifungal activities. Also Compounds A8 and A10 showed desirable antifungal activities against C. neoformance and C. parapsilosis, respectively. The antibacterial activities of the synthesized compounds were also evaluated. Compounds A6 - A10 against E. Fecalis and compounds A5, A7, A9 and A10 against P. aeruginosa showed desirable antibacterial activities. Discussion: We have synthesized some new Mannich adducts of poly-hydroxyl phenols in the presence of nano-ZnO as a reusable catalyst, with the hope of discovering new lead compounds serving as potent antimicrobial agents. The advantages of this method are generality, high yields with short reaction times, simplicity, low cost and matching with green chemistry protocols. The antimicriobial studies of Mannich derivatives of phenols showed desirable results in vitro.

scholarly journals Novel Derivatives of 4-Methyl-1,2,3-Thiadiazole-5-Carboxylic Acid Hydrazide: Synthesis, Lipophilicity, and In Vitro Antimicrobial Activity Screening

2021 ◽  
Vol 11 (3) ◽  
pp. 1180
Author(s):  
Kinga Paruch ◽  
Łukasz Popiołek ◽  
Anna Biernasiuk ◽  
Anna Berecka-Rycerz ◽  
Anna Malm ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Carboxylic Acid ◽  
Bacterial Infections ◽  
Acid Hydrazide ◽  
Antimicrobial Effect ◽  
In Vitro Antimicrobial Activity ◽  
Research Goal ◽  
New Compounds ◽  
Derivatives Of

Bacterial infections, especially those caused by strains resistant to commonly used antibiotics and chemotherapeutics, are still a current threat to public health. Therefore, the search for new molecules with potential antimicrobial activity is an important research goal. In this article, we present the synthesis and evaluation of the in vitro antimicrobial activity of a series of 15 new derivatives of 4-methyl-1,2,3-thiadiazole-5-carboxylic acid. The potential antimicrobial effect of the new compounds was observed mainly against Gram-positive bacteria. Compound 15, with the 5-nitro-2-furoyl moiety, showed the highest bioactivity: minimum inhibitory concentration (MIC) = 1.95–15.62 µg/mL and minimum bactericidal concentration (MBC)/MIC = 1–4 µg/mL.

scholarly journals Derivatives of 2-Aminopyridines as Inhibitors of Multidrug Resistant Staphylococcus Aureus Strains

2018 ◽  
Vol 10 (1) ◽  
pp. 153
Author(s):  
Iniobong E. Ante ◽  
Sherifat A Aboaba ◽  
Hina Siddiqui ◽  
Muhammad A Bashir ◽  
Muhammad I Choudhary
Keyword(s):  
Staphylococcus Aureus ◽  
Mass Spectra ◽  
Multidrug Resistant ◽  
Drug Resistant ◽  
Acid Chlorides ◽  
Alamar Blue ◽  
Standard Drug ◽  
Starting Point ◽  
New Compounds ◽  
Derivatives Of

A new series of 2-aminopyridine derivatives were synthesised. N-acylation of 2-amino-3-chloro-5-(trifluoromethyl) pyridine and 2-amino-5-(trifluoromethyl) pyridine with series of acid chlorides afforded a total of fourteen (14) amide compounds. The structures of the new compounds have been established by their IR, NMR and mass spectra data. All the compounds were tested for their activity against four (4) multi-drug resistant (MDR) bacteria Staphylococcus aureus strains using microplate alamar blue assay. The MDR-Staphylococcus aureus strains employed for this study were Epidermic Methicilin Resistant Staphylococcus aureus (EMRSA-17), Methicilin Resistant Staphylococcus aureus (MRSA-252), Epidermic Methicilin Resistant Staphylococcus aureus (EMRSA-16) and Pakistani Drug resistant clinical isolate of Staphylococcus aureus (PRSA). Other bacteria strains also used include Escherichia coli (ATCC 2592), Shigella flexenari (ATCC 12022), Staphylococcus aureus (NCTC 6571) and Pseudomonas aeruginosa (NCTC 10662). The synthesised compounds exhibited very good activity against the four MDR-Staphylococcus aureus strains of which most of the compounds showed higher potencies for inhibiting the growth of the strains than vancomycin, the standard drug employed. The compounds reported here may serve as the starting point for the design and development of MDR-S.aureus inhibitors as antibacterial agents.

Formation of acetaldehyde from threonine by lactic acid bacteria

1976 ◽  
Vol 43 (1) ◽  
pp. 75-83 ◽  
Author(s):  
G. J. Lees ◽  
G. R. Jago
Keyword(s):  
Free Amino ◽  
Thiol Group ◽  
Nutritional Requirement ◽  
Threonine Dehydratase ◽  
Threonine Aldolase ◽  
Streptococcus Cremoris ◽  
Dependent Inhibition ◽  
Ph Dependent ◽  
Dehydratase Activity ◽  
Derivatives Of

SummaryGroup N streptococci were found to cleave threonine to form acetaldehyde and glycine. Threonine aldolase, the enzyme catalysing this reaction, was found in all strains exceptStreptococcus cremorisZ8, an organism which had been shown previously to have a nutritional requirement for glycine. The enzyme was strongly inhibited by glycine and cysteine. The inhibition showed characteristics of allosteric inhibition and was pH-dependent. Inhibition by glycine, but not by cysteine, was highly specific. Analogues and derivatives of cysteine which contained a thiol group and a free amino group inhibited the activity of threonine aldolase. The presence of a carboxyl group was not necessary for inhibition. The cleavage of threonine by wholecell suspensions was stimulated by either an energy source to aid transport, or by rendering the cells permeable to substrate with oleate. Threonine did not appear to be degraded by enzymes other than threonine aldolase, as threonine dehydratase activity was low and NAD- and NADP-dependent threonine dehydrogenases were absent.

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