An unexpected tandem cycloaddition reaction of α,β-unsaturated acid chloride with amines: Synthesis of dihydropyrancarboxamide derivatives and biological activity

Tandem cycloaddition reaction of α,β-unsaturated acid chloride with amines afforded in situ N-acylated amines, which undergoes cycloaddition reaction with other molecule of acid chloride to give dihydropyran carboxamide derivatives as an unexpected product. 2-Amino benzimidazole, 2-aminobenzthiazole, 2-aminothiazole, anthranilic acid, o-pheneylenediamine, and 3-methyl-1H-pyrazol-5(4H)-one are reacted with methacryloyl chloride at 0 °C to give different derivatives of dihydropyran carboxamide. The latter compound was obtained through acylation of the organic amines followed by tandem cycloaddition reaction. In contrast acryloyl chloride afforded only N-acylated derivatives. Both products are characterized by single crystal X-ray diffraction method. Bioactivity of the newly synthesized products was studied against Gram-positive, Gram-negative bacteria and fungus

Analysis of Generalized Inverted Exponential Distribution under Adaptive Type-I Progressive Hybrid Censored Competing Risks Data

The estimation of the unknown parameters of generalized inverted exponential distribution under adaptive type-I progressive hybrid censored scheme (AT-I PHCS) with competing risks data will be discussed. The reason why AT-I PHCS has exceeded other failure censored types; Time censored types enable analysts to accomplish their trials and experiments in a shorter time and with higher efficiency. In this regards, we obtain the maximum likelihood estimation of the parameters and the asymptotic confidence intervals for the unknown parameters. Further, Bayes estimates of the parameters which obtained based on squared error and LINEX loss functions under the assumptions of independent gamma priors of the scale parameters. For Bayesian estimation, we take advantage of Markov Chain Monte Carlo techniques to derive Bayesian estimators and the credible intervals. Finally, two data sets with Monte Carlo simulation study and a real data set are analyzed for illustrative purposes

Purification and characterization of alginate lyase from locally isolated marine Pseudomonas stutzeri MSEA04

An alginate lyase with high specific enzyme activity was purified from Pseudomonas stutzeri MSEA04, isolated from marine brown algae. The alginate lyase was purified by precipitation with ammonium sulphate, acetone and ethanol individually. 70% ethanol fraction showed maximum specific activity (133.3 U/mg). This fraction was re-purified by anion exchange chromatography DEAE- Cellulose A-52. The loaded protein was separated into 3 peaks. The second protein peak was the major one which contained 48.2% of the total protein recovered and 79.4% of the total recovered activity. The collected fractions of this peak were subjected to further purification by re-chromatography on Sephadex G-100. Alginate lyase activity was fractionated in the Sephadex column into one major peak, and the specific activity of this fraction reached 116 U/mg. The optimal substrate concentration, pH and temperature for alginate lyase activity were 8 mg/ml, pH 7.5 and 37 °C, respectively. While, Km and Vmax values were 1.07 mg alginate/ ml and 128.2 U/mg protein, respectively. The enzyme was partially stable below 50 °C, and the activity of the enzyme was strongly enhanced by K+, and strongly inhibited by Ba+2, Cd+2, Fe+2 and Zn+2. The purified enzyme yielded a single band on SDS-PAGE with molecular weight (40.0 kDa)

(Z)-3-(4-Methoxy­anilino)-1-phenyl­but-2-en-1-one

In the title compound, C17H17NO2, the dihedral angle between the two benzene rings is 6.9 (1)°. The meth­oxy group is twisted slightly away from the aniline ring [C—O—C—C = 12.2 (3)°]. An intra­molecular N—H⋯O hydrogen bond generating an S(6) ring is observed. The crystal packing is stabilized by weak C—H⋯O and C—H⋯π inter­actions, forming a two-dimensional network

(Z)-3-Anilino-1,3-diphenylprop-2-en-1-one

In the title compound, C21H17NO, the phenyl ring directly linked to the carbonyl group is oriented at an angle of 7.3 (2)° with respect to the aniline ring, and at an angle of 55.6 (2)° with respect to the other phenyl ring. There is an intra­molecular hydrogen bond involving the NH group and the carbonyl O atom. The crystal structure is stabilized by weak C—H⋯π inter­actions, which link the mol­ecules into a herringbone arrangement

(Z)-3-[1-(4-Methoxy­anilino)ethyl­idene]-4,5-dihydro­furan-2(3H)-one

In the title compound, C13H15NO3, the dihydro­furan­one ring is planar to within 0.012 (4) Å and it forms a dihedral angle of 42.8 (2)° with the benzene ring. The amino­ethyl­idene group is coplanar with the dihydro­furan­one ring. The meth­oxy group is slightly twisted away from the benzene ring. An intra­molecular N—H⋯O hydrogen bond, generating an S(6) ring, is observed. In the crystal structure, the mol­ecules exist as C—H⋯O hydrogen-bonded dimers

Monoclinic form of (Z)-1-ferrocenyl-3-(3-hy­droxy­anilino)but-2-en-1-one

The title compound, [Fe(C5H5)(C15H14NO2)], is a monoclinic polymorph of the previously reported triclinic form [Shi et al. (2006 ▶). Acta Cryst. C62, m407–m410]. The polymorphs feature the same strong intra­molecular N—H⋯O=C hydrogen bonds, but show different packing modes. The mol­ecules in the monoclinic form associate into double chains via O—H⋯O=C and (Cp)C—H⋯O—H inter­actions

Ethyl (Z)-4-ferrocenyl-2-(4-hy­droxy­anilino)-4-oxobutenoate

In the title compound, [Fe(C5H5)(C17H16NO4)], the O=C—C=C—N mean plane is twisted with respect to the mean planes of the benzene and substituted cyclo­penta­dienyl rings by 44.2 (2) and 13.8 (3)°, respectively. Furthermore, the O=C—C=C—N mean plane and the O=C—O(ester) plane make a dihedral angle of 55.5 (6)°. Consistent with this large dihedral angle, the linking C—C bond [1.507 (6) Å] does not show any (delocalized) double-bond character

Calibration of a Neutron Polarimeter

This research was sponsored by the National Science Foundation Grant NSF PHY-931478