3,3′-Di-tert-butyl-5,5′-dimethoxy­biphenyl-2,2′-diol

The title compound, C22H30O4, displays twofold rotational symmetry. The two benzene rings are almost perpendicular to each other, forming a dihedral angle of 89.8 (6)°. In the crystal, mol­ecules are linked into an extended one-dimensional chain structure via inter­molecular O—H⋯O hydrogen bonds

Simultaneous and Direct Determination of Vancomycin and Cephalexin in Human Plasma by Using HPLC-DAD Coupled with Second-Order Calibration Algorithms

A simple, rapid, and sensitive method for the simultaneous determination of vancomycin and cephalexin in human plasma was developed by using HPLC-DAD with second-order calibration algorithms. Instead of a completely chromatographic separation, mathematical separation was performed by using two trilinear decomposition algorithms, that is, PARAFAC-alternative least squares (PARAFAC-ALSs) and self-weight-alternative-trilinear-decomposition- (SWATLD-) coupled high-performance liquid chromatography with DAD detection. The average recoveries attained from PARAFAC-ALS and SWATLD with the factor number of 4 (N = 4) were 101 ± 5% and 102 ± 4% for vancomycin, and 96 ± 3% and 97 ± 3% for cephalexininde in real human samples, respectively. The statistical comparison between PARAFAC-ALS and SWATLD is demonstrated to be similar. The results indicated that the combination of HPLC-DAD detection with second-order calibration algorithms is a powerful tool to quantify the analytes of interest from overlapped chromatographic profiles for complex analysis of drugs in plasma

trans-Diaqua­bis­[5-carb­oxy-4-carboxyl­ato-2-(4-pyridinio)-1H-imidazol-1-ido-κ2 N 3,O 4]zinc(II)

In the title complex, [Zn(C10H6N3O4)2(H2O)2], the ZnII atom is located on a twofold rotation axis and is coordinated by two trans-positioned N,O-bidentate and zwitterionic 5-carb­oxy-4-carboxyl­ato-2-(4-pyridinio)-1H-imidazol-1-ide (H2PIDC−) ligands and two water mol­ecules, defining a distorted octa­hedral environment. The complete solid-state structure can be described as a three-dimensional supra­molecular framework, stabilized by extensive hydrogen-bonding inter­actions involving the coordinated water mol­ecules, uncoordin­ated imidazole N atom, protonated pyridine N and carboxyl­ate O atoms of the H2PIDC− ligands

N-(5-Amino-1H-tetra­zol-1-yl)formamide

In the title compound, C2H4N6O, the planar [maximum deviation = 0.006 (2) Å] amino­tetra­zole group makes a dihedral angle of 83.65 (8)° with the formamide unit. In the crystal structure, inter­molecular N—H⋯N, N—H⋯O and C—H⋯N hydrogen bonds are responsible for the formation of a three-dimensional network

2-(2-Furylmethyl­ammonio)ethane­sulfonate methanol solvate

The organic mol­ecule of the title compound, C7H11NO4S·CH3OH, is a zwitterion and its furan ring displays positional disorder [occupancy 0.563 (5):0.437 (5)]. The crystal structure is extended into a three-dimensional supra­molecular architecture through inter­molecular O—H⋯O and N—H⋯O hydrogen bonds with participation of the methanol solvent mol­ecules

N-(1-Diacetyl­amino-1H-tetra­zol-5-yl)acetamide

In the crystal structure of the title compound, C7H10N6O3, there are N—H⋯O, N—H⋯N and C—H⋯O inter­actions, generating a three-dimensional supra­molecular network structure. A short intermolecular O⋯C contact of 2.8994 (18) Å is alsopresent in the crystal structure, but no π–π contacts are observed

1-Isopropyl­ideneamino-1H-tetra­zol-5-amine

The mol­ecule of the title compound, C4H8N6, assumes an approximately planar structure, the methyl C atoms and the C atom to which they are bonded being out of the mean tetrazole ring plane by 0.108 and 0.139, and 0.144 Å, respectively. π–π stacking between parallel tetra­zole rings [centroid–centroid distance = 3.4663 (11) Å] is observed in the crystal structure. Inter­molecular N—H⋯N hydrogen bonding further helps to stabilize the crystal structure