Scission of oxiranes by acid anhydrides to unsaturated alcohol esters

The reactions of some 1-R-3-methyl-2,3-epoxybutanes with acetic and propionic anhydrides takes place at 140–160C, regioselectively, with the formation of -metallyl alcohol esters.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 309–312, March, 1989.     

Investigation of the reaction of some unsaturated dicarboxylic acid anhydrides with cyclic carbonates

This work reports attempts to extend to unsaturated anhydrides the rapid reaction of dicarboxylic acid anhydrides with ethylene carbonate to form polymer directly. The reaction of unsaturated diacid anhydrides with two cyclic carbonates, ethylene and propylene carbonate, leads to gelled products whenever the anhydride is capable of Michael addition, while an anhydride without such unsaturation gave linear polymer in- stead. The GC/MS results, along with efforts to trap radical reactions, support Michael addition as an explanation of gelation in these systems.     

Raman spectra of phenothiazine and some pharmaceutical derivatives

The laser-Raman spectra of several phenothiazines in the region 600-1600 cm(-1) are reported. The major bands are assigned to ring modes or to vibrations of the alkyl side-chains.     

Molecular structures of edge-sharing square-planar dinuclear complexes with unsaturated bridges

The dinuclear complexes of transition metal ions of type [M(2)(mu,eta(1)-XY)(2)L(4)], where XY is an unsaturated ligand that can act as a four-electron or a two-electron donor through the X atom, appear in two molecular conformations depending on whether the coordination planes around the two metal atoms are coplanar or bent. In both structures the geometry of the X atom is planar, corresponding to an sp(2) hybridization. An ab initio theoretical study on 43 representative complexes, complemented with a structural database analysis, provides a rationale for the experimentally observed structures.     

Reaction of primary and secondary enamines with anhydrides of unsaturated dicarboxylic acids

It was established that donor-acceptor complexes are formed in the reaction of some conjugated enamines with anhydrides of unsaturated dicarboxylic acids; in all likelihood, this constitutes evidence in favor of a scheme that includes nucleophilic addition of the enamine to the double bond. Addition of this type with subsequent intramolecular cyclization leads to the formation of ²-pyrrolin-5-ones. In the case of citraconic anhydride it is shown (on the basis of data from the PMR and mass spectra) that nucleophilic attack is directed to the unsubstituted carbon atom of the ethylene bond.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 474–476, April, 1977.     

Phosphomolybdic acid as a reagent for the spectrophotometric determination of certain phenothiazine derivatives of pharmaceutical products

Phosphomolybdic acid is used as reagent for colorimetric determination of phenothiazine derivatives in various pharmaceutical products. The reagent oxidizes the derivative to a cationic free radical, with which it then forms a coloured salt. The method is simple and rapid. A preliminary extraction is necessary if certain reductants (sulphite or ascorbic acid) are present as stabilizers of the pharmaceuticals, as otherwise they reduce the reagent to phosphomolybdenum blue.     

Stability of photocurable anhydrides: Methacrylic acid mixed anhydrides of nontoxic diacids

Disproportionation of the liquid mixed anhydride dimethacrylic sebacic anhydride (m‐SA) to methacrylic anhydride and polyanhydride oligomers, as well as vinylic polymerization, can occur on workup and storage at room temperature. Dimethacrylic 1,3‐bis(p‐carboxyphenoxy) propane, being a solid, can also disproportionate, but the propensity to do so is lower than for m‐SA. These events can be suppressed with free‐radical inhibitors, and the inhibitor 2+3‐t‐butyl‐4‐methoxyphenol is a more effective stabilizer than 4‐methoxyphenol at 20 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4189–4195, 2001     

Free radical addition of F-alkyl compounds to unsaturated carboxylic anhydrides and their derivatives

Many perfluoroalkyl-substituted organic compounds have been obtained through free radical addition of F-alkyl iodides to a center of unsaturation:

X, Y, and Z may include carbon chains, rings and various substituents. During the course of these synthetic studies—done over a span of several years—significant discoveries in mechanism and structure have been made.Today I wish to report some free radical additions of F-alkyl iodides to unsaturated anhydrides and their derivatives. Among the compounds recently discovered are the norbornene products 5 to 10.

Spectroscopic properties of the adducts varied with position and nature of the substituents. Somewhat surprisingly, the chemical shift of protons on the R_F side of the molecule was affected by changes in substituents on the other side of the molecule.Various reactions of the adducts were studied. Unusual stereospecificity in lactone formation and in base- induced cyclization to nortricyclene derivatives was observed. Only when the iodo group was in an endo position did these reactions occur.Analogous free radical addition of fluorinated thiols (R_FCH₂CH₂SH) to norbornene anhydrides produced a series of 5-polyfluoroalkylthionorbornane-2,3-dicarboxylic acid anhydrides(11, 12; U S Patent 3,989,725 (1976). As in previous studies the entering group took up the exo position exclusively. Reaction with acids, esters or norbornene carboxylic imides of the fluorinated thiol also gave analogous products.Because of the hydrophobic nature of the F-alkyl groups the entire range of compounds displayed pronounced surface-activity and would appear to have utility in a wide range of applications.

     

Extractive spectrophotometric determination of some phenothiazine derivatives in pharmaceutical preparations

A simple, accurate, rapid and sensitive spectrophotometric method has been developed for the assay of six phenothiazine derivatives in bulk drug and their pharmaceutical preparations. The method is based on ion-pair complex reaction of phenothiazines with bromocresol green in aqueous acidic buffer. The chromogen, being extractable with chloroform, could be measured quantitatively at 420 nm. All variables were studied in order to optimize the reaction conditions. The proposed method has been successfully applied to the analysis of the bulk drugs and their dosage forms, tablets and injections. No interference was observed from common pharmaceutical adjuvants. Statistical comparison of the results with those of an official method shows excellent agreement and indicates no significant difference in precision.     

Extractive spectrophotometric determinations of some phenothiazine derivatives in pharmaceutical preparations

Two sensitive methods for the determination of phenothiazine derivatives based on the formation of coloured salts of these drugs formed with Brilliant Blue or Orange-II in the presence of 0.1 M HCl are described. The ion pair salts formed are quantitatively extracted into chloroform and the dried chloroform solutions analyzed using spectrophotometry.     

Acylation of benzimidazolone and its derivatives with acid anhydrides and acid chlorides

N,N-Diacetyl derivatives of benzimidazolones were obtained by the acylation of benzimidazoline and its 5-methyl, 5-chloro, and 5-nitro derivatives with acetic, propionic, and butyric anhydrides and also with monochloro- and monobromoacetyl chlorides.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 386–389, March, 1972.     

New reactions of phenothiazine green cations and their metal complexes

New reactions of phenothiazine green cations and their complexes with copper and iron chlorides of both ionic and radicalic type leading to C- and N-derivatives of 3,10′-diphenothiazine are described.     

Phase transfer catalysis in N-alkylation of the pharmaceutical intermediates phenothiazine and 2-chlorophenothiazine

The N-alkylation of the two title compounds was studied, utilizing phase transfer catalysis (PTC) methods. Very mild reaction conditions were developed, especially for three-carbon N-alkylation. Of special interest is the high-yield synthesis of N-(3-chloropropyl)-2-chlorophenothiazine. The results are discussed in terms of the classical PTC/OH⁻ mechanisms.     

Charge-transfer complexes of phenothiazine derivatives with π-electron acceptors

Charge-transfer complexes (CTC) of some phenothiazine derivatives with -electron acceptors were obtained. They were used to determine the ionization potentials of the investigated donor compounds. The complexing constants of phenothiazine and some of its N-substituted derivatives were found. The experimental data obtained make it possible to draw conclusions relative to their configurations.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 497–501, April, 1973.