Equivalents Of NaOH Research Articles

Radiosynthesis of a chloroacetanilide herbicide ([phenyl‐4‐3H] acetochlor) and a dichloroacetamide safener for herbicides ([2, 2‐dimethyl‐3H]R‐29148)

Abstract2‐Chloro‐N‐(ethoxymethyl)‐N‐(2‐ethyl‐6‐methylphenyl)acetamide (the chloroacetanilide herbicide acetochlor) and 3‐(dichloroacetyl)‐ 2,2,5‐trimethyl‐1,3‐oxazolidine (the dichloroacetamide safener R‐ 29148) are required at high specific activity for studies on their metabolism and mode of action. [phenyl‐4‐3H]Acetochlor was obtained at 22 Ci/mmol in 71% yield by reductive dehalogenation of iodoacetochlor with tritium gas in ethanol in the presence of palladium on carbon and triethylamine. [2,2‐dimethyl‐3H]R‐29148 was prepared at 15 Ci/mmol by treating acetone and 1‐amino‐2‐propanol in pentane with two equivalents of NaOH in tritiated water (i.e. hydroxide ion‐catalyzed enolization of acetone) followed by dichloroacetyl chloride.

Dalton communications. The synthesis of the first examples of water-soluble seven-co-ordinate complexes of tungsten(II)

Reaction of the seven-co-ordinate complex [WI2(CO)3(NCMe)2] with two equivalents of 4-HO2CC5H4N in methanol at room temperature gave the bis(pyridine-4-carboxylic acid) complex [Wl2(CO)3(4-HO2CC5H4N)2]1 in good yield, which, upon treatment with two equivalents of NaOH in ethanol, afforded the completely water-soluble complex [Wl2(CO)3(4-NaO2CC5H4N)2]2 in good yield; reaction of the latter with an equimolar amount of 3-NaO3SC5H4N yielded [Wl2(CO)3(4-NaO2CC5H4N)(3-NaO3SC5H4N)], which represents the first room-temperature ligand-substitution reaction in water of a metal carbonyl complex.

Studies on chitosan: 3. Evidence for the presence of random and block copolymer structures in partially N-acetylated chitosans

The chemical structures of moderately N-deacetylated chitosans (MDC) derived from chitin under heterogeneous reaction conditions and partially N-acetylated chitosans (PAC) derived from highly N-deacetylated chitosans (HDC) under homogeneous reaction conditions were deduced from the data of the stability of their solutions in alkaline media, the swelling behaviour and X-ray diffraction patterns of their films in connection with the degree of N-acetylation of them. The solutions of PAC with more than 51% acetyl content, which were prepared from HDC by N-acetylation, were stable and remained clear and homogeneous by adding 1.2 equivalents of NaOH. On the contrary the solutions of PAC with more than 52% acetyl content, which were prepared from MDC, became turbid by neutralization with less than 1.15 equivalents of NaOH. The films of PAC prepared from HDC were highly swollen in water. The degree of swelling of the chitosan film with 51% acetyl content, prepared from the 6% acetyl content chitosan, was 121% while that of the 53% acetyl content chitosan, prepared from the 30% acetyl content chitosan, was 28%. From these data it was possible to set up a hypothesis that PAC prepared from HDC were considered as random-type copolymers of N-acetyl-glucosamine and glucosamine units whereas MDC were considered as block-type copolymers.

Erosion Process of a Dental Polycarboxylate Cement

Erosion process of the zinc polycarboxylate cement in various acid solutions was investigated by means of determination of Zn and Mg leached from the cement and SEM observation of the surface structure. The amount of species leached from the cement increased with increasing dissociation constant of the acid, that is, with decreasing pH of the solution. Partial neutralization of the acid decreased the amounts of Zn and Mg. When the degree of neutralization (=equivalent of NaOH added/equivalent of the acid originally present) reached 1, the amount leached was almost negligible. However, in the acids which formed stable complexes with Zn and Mg, certain amounts of Zn and Mg were released from the cement. Especially with EDTA which formed much stable complexes, the amount leached was independent of the degree of neutralization and showed high value. Erosion of the cement in the acid solutions consisted of two competitive processes, that is, dissolution of the unreacted ZnO particles and erosion of the matrix. The preference of these two processes depends on the dissociation constants of the acids and the formation constants of the complexes between the acids and Zn or Mg. The former occurs preferentially at a lower degree of neutralization. The latter also proceeds in strong acids such as HCl or in acids forming stable complexes such as citric acid and EDTA. With increasing degree of neutralization, erosion of the matrix occurs exclusively with ZnO particles taken off the cement in the latter two acids.

Nickel(II) and cobalt(II) complexes of rhodanine

Nickel(II) and cobalt(II) complexes of rhodanine (Hrd) were prepared from the metal chloride or acetate and the ligand. With an excess of NH3, the octahedral [Ni(NH3)6](Rd)2 and [Co(NH3)5Rd]Rd complexes are ob-tained; use of only two NH3 equivalents per metal ion yields the Ni(Rd)2 sd HRd · NH3 and [Co(Rd)2 ] · 1.5 H2O complexes, the first with tetragonally distorted hexacoordination and the second with polymeric octahedral coordination. By using two equivalents of NaOH per metal ion, the binuclear [Ni(Rd)2][Ni(Rd)2 · (HRd)2] · 2 H2O complex is formed having one diamagnetic planar and one high spin octahedral chromophore. Rhodanine is coordinated through the thiocarbonylic sulphur in the neutral form and through the thiocarbonylic sulphur and the deprotanated nitrogen atoms in the rhodanidato anionic form.

Recherches sur la formation et la transformation des esters LXXXI [1]. Sur la réaction d'isothiocyanates avec l'acide hydrazinoéthylphosphorique, et de l'isocyanate de phényle avec l'acide colaminephosphoreux

AbstractHydrazinoethyl phosphoric monoester has been prepared by reacting hydrazinoethanol with polyphosphoric acid, and isolated as di‐sodium salt.Sodium hydrazinoethyl phosphate reacts with phenylisothiocyanate (in H2O+ethanol) to yield mainly the derivative thiocarbamoylated at the substituted nitrogen atom. This derivative, heated for one night at 100° in 0.5 N HCl, is cyclized to 3‐amino‐2‐phenylimino‐thiazolidine in 62% yield. Sodium hydrazinoethyl phosphate reacts with o‐methoxycarbonylphenyl isothiocyanate (in H2O+dioxane) at the unsubstituted nitrogen atom to yield mainly the corresponding quinazoline derivative (IV, X = OPO3Na2). This derivative, heated for one night at 100° in 0.5 N HCl, is cyclized to 2‐o‐carboxyphenylamino‐dihydro‐δ2‐1, 3, 4‐thiadiazine (Va) in 55% yield (hydrolysis of the lactamic function as well).Aminoethyl phosphorous monoester (colaminephosphorous acid) reacted with phenylisocyanate (in H20+dioxane) in slightly alkaline medium (one equivalent of NaOH) yields sodium N‐phenylcarbamoylaminoethyl phosphite. Refluxed for 20 minutes in 1N NaOH, this carbamoyl derivative is not cyclized but only hydrolyzed to the open‐chained N‐phenyl‐N′‐hydroxyethylurea (VII).

Recherches sur la formation et la transformation des esters LXXIX [1]. Sur la réaction de l′isothiocyanate d′o‐méthoxycarbonyl‐phényle avec divers acides et l′acide sérinephosphorique

AbstractAmino acids devoid of «leaving groups» on their β carbon atom (neither OH: serine, nor SH: cysteine) react with o‐methoxycarbonyl‐phenyl isothiocyanate (I) in the presence of one equivalent of NaOH, in water‐dioxane or in ethanol, to yield the corresponding hydroquinazolinone derivatives II which were isolated as free acids.When treated with CH3COOH + conc. HCl the hydroquinazolinone resulting from the reaction of L‐serine with I undergoes a nucleophilic attack of the carbon bearing the leaving group OH by a lone pair of electrons of S; this attack produces the formation of an additional thiazolidine ring, yielding the thiazoloquinazolinone derivative (−)‐III. In an analogous reaction DL‐serine phosphoric acid treated with I at pH 8–9 yields the corresponding substituted hydroquinazolinone which, boiled in 1N hydrochloric acid, undergoes ring closure to (±)‐III by the same mechanism as the serine derivative (leaving group: OPO3H2).L‐Cysteine reacted with 2 equiv. of I and then treated with CH3COOH + conc. HCl gives two products: (−)‐III produced by the same mechanism as for serine (leaving group: SH), and the quinazolinone derivative IV where the SH group is also thiocarbamoylated.

Recherches sur la formation et la transformation des esters LXXIII Sur la préparation d'acides ω‐[aryl (ou aralcoyl ou alcoyl) carbamylamino]‐alcoylphosphoriques et sur leur vitesse de scission à divers pH

AbstractN‐Aryl(or aralkyl or alkyl)carbamoyl‐aminoalkyl phosphoric monoesters have been prepared by the reaction of isocyanates R′‐NCO on the corresponding amino‐alkylphosphoric monoesters H2NROPO3H2 in the presence of 2 equivalents of NaOH. The rates of scission of the phosphoric monoester group and occasionally of the phenylcarbamoylamino group of these monoesters have been studied at 100°, in solutions 0.1M in ester and at various pH.