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author:("ambronn, Nida")
1.  Benzimidazole, coumrindione and flavone derivatives as alternate UV laser desorption ionization (LDI) matrices for peptides analysis 
Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization mass spectrometric technique, allowing the analysis of bio-molecules and other macromolecules. The matrix molecules require certain characteristic features to serve in the laser desorption/ionization mechanism. Therefore, only a limited number of compounds have been identified as ultraviolet- laser desorption/ionization (UV-LDI) matrices. However, many of these routine matrices generate background signals that useful information is often lost in them. We have reported flavones, coumarindione and benzimidazole derivatives as alternate UV-LDI matrices.
Thirty one compounds have been successfully employed by us as matrices for the analysis of low molecular weight (LMW) peptides (up to 2000 Da). Two peptides, bradykinin and renin substrate tetra-decapeptide were analyzed by using the newly developed matrices. The MS measurements were made after mixing the matrix solution with analyte by using dried droplet sample preparation procedures. The synthesized matrix materials showed better S/N ratios and minimal background signals for low mass range. Furthermore, pico molar concentrations of [Glu1]-fibrinopeptide B human could be easily analyzed with these matrices. Finally, BSA-digest was analyzed and identified through database search against Swiss-Prot by using Mascot.
These results validate the good performance of the synthesized UV-laser desorption/ionization (LDI) matrices for the analysis of low molecular weight peptides.
PMCID: PMC3680071  PMID: 23621998
MALDI-MS; LDI matrix; Benzimidazole derivatives; Coumarin derivatives; Flavones; Peptides
2.  5-Chloro-2-(4-meth­oxy­phen­yl)-1,3-benzo­thia­zole 
In the title compound, C14H10ClNOS, the dihedral angle between the benzothia­zole ring system and the meth­oxy-substituted benzene ring is 8.76 (16)°. In the crystal, mol­ecules are stacked in columns along the c axis and no significant inter­molecular inter­actions are observed.
PMCID: PMC3588450  PMID: 23476550
3.  5-Chloro-2-(3,4,5-trimeth­oxy­phen­yl)-1,3-benzothia­zole 
In the title compound, C16H14ClNO3S, the dihedral angle between the almost-planar benzothia­zole ring system [maximum deviation = 0.012 (3) Å] and the aromatic ring of the trimeth­oxy­phenyl group is 15.56 (6)°. In the crystal, the mol­ecules are arranged into layers parallel to the bc plane, held together only by weak van der Waals forces.
PMCID: PMC3470404  PMID: 23125817
4.  Ethyl (E)-3-(6-methyl-4-oxo-4H-chromen-3-yl)prop-2-enoate 
In the title compound, C15H14O4, the chromone ring system is close to being planar [maximum deviation = 0.015 (2) Å]. The double bond of the ethyl prop-2-enoate chain adopts an E conformation and an intra­molecular C—H⋯O hydrogen bond generates an S6 ring. In the crystal, inversion dimers linked by pairs of C—H⋯O hydrogen bonds generate R 2 2(14) loops. Weak π–π inter­actions [centroid–centroid distance = 3.8493 (12) Å] also occur.
PMCID: PMC3470320  PMID: 23125733
5.  6-Methyl-4-oxo-4H-chromene-3-carbaldehyde 
In the title compound, C11H8O3, the benzopyran-4-one or chromone ring system is almost planar, with a maximum deviation of 0.045 (2) Å. The crystal structure is stablized by π–π inter­actions between the benzene and pyran rings of inversion-related mol­ecules stacked along the b axis, with a centroid–centroid distance of 3.5463 (12) Å
PMCID: PMC3470266  PMID: 23125710
6.  2-(5-Chloro-1,3-benzothia­zol-2-yl)-4-meth­oxy­phenol 
In the mol­ecule of the title compound, C14H10ClNO2S, the dihedral angle between the almost planar benzothia­zole ring system [maximum deviation = 0.005 (2) Å] and the benzene ring is 1.23 (9)°. The conformation of the mol­ecule is stabilized by an intra­molecular O—H⋯N hydrogen bond, forming an S(6) ring motif. In the crystal, mol­ecules are linked into layers parallel to the ac plane by C—H⋯O hydrogen bonds and π–π stacking inter­actions [centroid–centroid distance = 3.7365 (12) Å].
PMCID: PMC3470231  PMID: 23125675
7.  5-Chloro-2-phenyl-1,3-benzothia­zole 
In the structure of the title compound, C13H8ClNS, the dihedral angle between the benzothia­zole ring system and the phenyl ring is 7.11 (8)°. In the crystal, mol­ecules are arranged parallel to the c axis.
PMCID: PMC3435826  PMID: 22969672
8.  1-(3-Meth­oxy­phen­yl)-2-(phenyl­sulfon­yl)ethan-1-one 
In the title compound, C15H14O4S, the dihedral angle between the benzene and phenyl rings is 88.74 (10)°. In the crystal, mol­ecules are linked into a three-dimensional network by C—H⋯O hydrogen bonds and π–π stacking inter­actions [centroid–centroid distances = 3.6092 (13)–3.8651 (13) Å].
PMCID: PMC3415004  PMID: 22904991
9.  8-[(2-Hy­droxy­phen­yl)imino]-3,5a,9-trimethyl-3a,4,5,5a,8,9b-hexa­hydro­naphtho­[1,2-b]furan-2(3H)-one 
The title compound, C21H23NO3, is a phenyl­imine derivative of the well known anthelmintic agent α-santonin. The trans-fused cyclo­hexane and γ-lactone rings of the α-santonin ring system adopt chair and envelope conformations, respectively, whereas the hexa­diene ring is approximately planar [maximum deviation = 0.029 (4) Å] and forms a dihedral angle of 62.30 (11)° with the benzene ring. An intra­molecular O—H⋯N hydrogen bond is observed.
PMCID: PMC3393965  PMID: 22798830
10.  3,5a,9-Trimethyl-8-(2-phenylhydrazin-1-ylidene)-4,5,5a,9b-tetrahydro-3aH,8H-naphtho[1,2-b]furan-2(3H)-one 
The title compound, C21H24N2O2, is a phenyl hydrazine derivative of the well known anthelminthic agent α-santonin, which is composed of three fused rings (benzodieneone, cyclo­hexane and γ-lactone). The cyclo­hexa­dienone ring adopts a boat conformation, the cyclo­hexane ring is in a chair conformation and the trans-fused γ-lactone ring adopts a C-envelope conformation. In the crystal, mol­ecules are linked by N—H⋯O and C—H⋯O hydrogen bonds, forming chains along the a axis.
PMCID: PMC3393924  PMID: 22798789
11.  3D-QSPR Method of Computational Technique Applied on Red Reactive Dyes by Using CoMFA Strategy 
Cellulose fiber is a tremendous natural resource that has broad application in various productions including the textile industry. The dyes, which are commonly used for cellulose printing, are “reactive dyes” because of their high wet fastness and brilliant colors. The interaction of various dyes with the cellulose fiber depends upon the physiochemical properties that are governed by specific features of the dye molecule. The binding pattern of the reactive dye with cellulose fiber is called the ligand-receptor concept. In the current study, the three dimensional quantitative structure property relationship (3D-QSPR) technique was applied to understand the red reactive dyes interactions with the cellulose by the Comparative Molecular Field Analysis (CoMFA) method. This method was successfully utilized to predict a reliable model. The predicted model gives satisfactory statistical results and in the light of these, it was further analyzed. Additionally, the graphical outcomes (contour maps) help us to understand the modification pattern and to correlate the structural changes with respect to the absorptivity. Furthermore, the final selected model has potential to assist in understanding the charachteristics of the external test set. The study could be helpful to design new reactive dyes with better affinity and selectivity for the cellulose fiber.
PMCID: PMC3257105  PMID: 22272108
3D-QSPR; CoMFA; red reactive dye; cellulose fiber

Results 1-11 (11)