A novel series of cyanopyridinyl tetrahydronaphthalene incorporated with different heterocycles were synthesized. The key compounds 2a,b were condensed with chloroacetone and ethyl chloroacetate to give 3a,b and 4a,b, respectively. Also condensation of 4a,b with hydrazine hydrate gave the corresponding hydrazide 5a,b. Reaction of 5b with different isothiocyanates gave the corresponding thiosemi...

Treatment of nucleosomal particles and isolated core-histone octamers with dimethylmaleic anhydride, but not with acetic anhydride, is accompanied by a biphasic release of the two H2A.H2B dimers, the first dimer being more easily released than the second. With both kinds of particles, 50% of histones H2A and H2B are released for modification of approximately 35% of the histone amino groups. The...

The wide-spread use of photoelectric calorimeters in the field of quantitative clinical chemistry has brought with it the realization that many of the visual calorimetric methods in use are grossly inaccurate and that their use may be justified only on the basis of an arbitrary range of normal values for the given procedure. This is particularly true in the case of total cholesterol values whic...

In a previous investigation du Vigneaud and Sealock (1) have reported that the sodium salt of acetyl-l-tryptophane in aqueous solution at 35-40” is completely racemized by acetic anhydride within a few hours. The ease of racemization and particularly the mild conditions under which the reaction occurred seemed to us to offer an excellent method for racemizing amino acids if the reaction should ...

E-mail: [email protected] Abstract: Different dextran esters with various degrees of substitution (1, 2 and 3) were synthesized by esterification reaction, with three acid anhydrides: acetic anhydride, propionic anhydride, and butyric anhydride, separately. These modified polysaccharides were characterized by FT-IR, H NMR and C NMR spectroscopies. Enzymatic degradation of biopolymers by dextr...

Six acylation reagents have been compared for their derivatisation potential towards nine synthetic cathinones by gas chromatography-mass spectrometry (GC-MS). The evaluated reagents were pentafluoropropionic anhydride (PFPA), trifluoroacetic anhydride (TFA), chlorodifluoroacetic anhydride (CLF2AA), heptafluorobutyric anhydride (HFBA), acetic anhydride (AA) and propionic anhydride (PA). The syn...

Dimethyl sulphoxide –acetic anhydride reagent brings about an easy conversion of 1,3-indandione to its corresponding derivatives.At room.temperature this reagent converts 1,3indandione to ylide(2),an unusual dimer(3) and a novel dimeric condensation product(6).However,at waterbath temperature it affords a spiran(8) along with (2) &(6).

Organosilicon-mediated, regioselective acetylation of vicinal- and 1,3-diols is presented. Methyl trimethoxysilane or dimethyl dimethoxysilane was first used to form cyclic 1,3,2-dioxasilolane or 1,3,2-dioxasilinane intermediates, and subsequent acetate-catalyzed monoacylation was efficiently performed by addition of acetic anhydride or acetyl chloride under mild conditions. The reaction exhibi...

the acetylation of various alcohols and phenols was performed successfully using acetic anhydride in the presence of citric acid coated magnetite nanoparticles as catalyst under solvent-free condition and at 45 °c. the catalyst showed high thermal stability and was recovered and reused at least 5 times without any considerable loss of activity. the present process is environmentally benign and ...

The purpose of this paper is to demonstrate the autocovariance least-squares (ALS) techniques to a laboratory reactor for the conversion of acetic anhydride to acetic acid. In this way, it is demonstrated that the methods proposed by Odelson and Rawlings are applicable to actual process data, and not just theoretical simulations. A variety of control scenarios are tested including: simple regul...