(4R*,5R*)-2-(4-Meth-oxy-phen-yl)-1,3-dioxolane-4,5-dicarboxamide.

In the title compound, C(12)H(14)N(2)O(5), the five-membered 1,3-dioxolane ring has a twisted conformation. In the crystal, N-H⋯O and C-H⋯O hydrogen bonds link the mol-ecules into a two-dimensional network lying parallel to the ab plane. There are also C-H⋯π inter-actions present in the crystal structure.

(4R*,5R*)-Diethyl 2-(4-nitro-phen-yl)-1,3-dioxolane-4,5-dicarboxyl-ate.

In the title compound, C(15)H(17)NO(8), the nitro group is essentially coplanar with the aromatic ring [dihedral angle = 6.4 (3) Å]. The five-membered ring has a twist conformation. In the crystal, C-H⋯O inter-actions link the mol-ecules into a helical chain propagating along [010].

2,6-Dibromo-4-(2-hy-droxy-eth-yl)phenol.

The title compound, C(8)H(8)Br(2)O(2), crystallized with two independent mol-ecules (A and B) in the asymmetric unit. They differ in the conformation of the 2-hy-droxy-ethyl chain with the C-C-C-O torsion angle being -68.0 (12)° in mol-ecule A and 172.2 (9)° in mol-ecule B. In the crystal, the A mol-ecules are linked via pairs of O-H⋯O hydrogen bonds, forming inversion dimers, while the B mol-ecules are linked via an O-H⋯O hydrogen bond, forming a polymeric chain propagating in [010]. In addition, there are O-H⋯O and O-H⋯Br hydrogen bonds, and Br⋯Br [3.599 (2) Å] and π-π inter-actions [centroid-centroid distances = 3.581 (6) and 3.931 (6) Å], leading to the formation of a two-dimensional network parallel to (001).

(S)-(+)-4-(Oxiran-2-ylmeth-oxy)-9H-carbazole.

In the title compound, C(15)H(13)NO(2), all atoms of the carbazole group are coplanar (r.m.s. deviation = 0.005 Å), and the dihedral angle between this plane and C-O-C plane of oxane group is 57.1 (4)°. The crystal packing is stabilized by an N-H⋯O hydrogen bond, resulting in infinite supra-molecular chains along [001].

Simultaneous Determination of Four Active Components in Tobacco Wastes by LC.

A liquid chromatographic method was developed for the simultaneous quantification of four major active components in tobacco (Nicotiana tobaccum L.) wastes. Samples were extracted with 70% v/v aqueous methanol, four compounds including chlorogenic acid, cryptochlorogenic acid, neochlorogenic acid and caffeic acid were identified and determined by using LC coupled to electrospray tandem mass spectrometry and LC-UV method, respectively. Separation in LC-UV was on an Alltima C18 column (250 mm × 4.6 mm i.d.; 5 µm) with a mobile phase consisting acetonitrile: ammonium acetate buffer (pH 4.5) (5:95 v/v), at a flow rate of 1.0 mL min-1, detected at 327 nm. Four regression equations showed good linear relationships (r 2 > 0.999) between the peak area of each marker and concentration. The method has good repeatability and precision, the intra-day and inter-day RSD for both retention time and peak area was less than 1.0%. The recoveries, measured at three concentration levels, varied from 96.33 to 101.10%. The LOD (S/N = 3) and LOQ (S/N = 6) were less than 0.010 and 0.795 µg·mL-1, respectively. This assay was successfully applied to the determination of four active compounds in ten samples. The results indicated that the developed assay method was rapid, accurate, reliable and could be readily utilized as a quantitative analysis method for various of tobacco wastes.

Biocatalytic properties of a novel crude glycyrrhizin hydrolase from the liver of the domestic duck.

A novel crude glycyrrhizin (GL) hydrolase preparation from the liver of domestic duck was used to produce glycyrrhetic acid monoglucuronide. To characterize the biocatalytic profiles of the crude enzyme, some effect factors were investigated. It had an apparent optimal pH of 6.0 and an optimal temperature at 55 °C. Most of the metal ions tested and ethylene diamine tetra acetic acid showed little effect on the crude enzyme activity except Cu2+. The enzyme was stable only at pH 6. It was more prone to inactivity at high pH conditions than at low pH conditions. It was stable at temperatures below 55 °C and it will lost 90% GL hydrolytic activity exposed at 70 °C. GL hydrolytic activity declined by 30% compared with the control in aqueous solution (buffer pH 6.0) when pre-equilibrated at 55 °C for 5 days. It indicated that the novel crude GL hydrolase preparation had good biocatalytic ability for selective hydrolysis of one glucuronic acid from GL.