Advanced Chemistry Development software

Effect of pH on the Retention/Selectivity of the Isomers. The first step in method development is to understand the effect of pH on the separation characteristics of the method. The pKa values of the ortho and the para isomers was estimated by ACD (Advanced Chemistry Development software) to be 9.0 and 9.5, respectively. Obviously the best pH to carry out the separation would be at pH that is less than 2 units lower than the analyte that has the lowest pKa. This would be at pH values less than 7.0. However, to illustrate the effect of pH on the separation selectivity of the isomers, a controlled pH study at isocratic conditions was conducted. 

ChemSketch is a professional software package that is available free of charge from Advanced Chemistry Development Inc. (ACD). Besides the editor, it has several modules (ACD/Dictionary, ACD/Tautomers), extensions, and add-ins concerning the calculation of physicochemical properties, input of spectra and chromatograms, naming of molecules, and a viewer. 

Advanced Chemistry Development (ACD) Software Solaris V4 (1994-2004) www.scifinder.scholar.com. 

Advanced Chemistry Development (ACD, Inc., Toronto, Ontario, Canada) software package version 8.0 was used to display the data as reconstructed mass spectra (Figure 10.6), as well as reflect spectra for comparison purposes (Figure 10.7) and display peaks that were not common between two spectra (Figure 10.8). 

A classic pharmaceutical science textbook might have defined poor solubility as anything below a solubility of 1 g mL-1 (2 mol L-1 solution for a molecular weight of 500 Da) at pH 6.5 (or pH 7). This classic view is reflected in the Chemical Abstracts SciFinder 2001 solubility range definitions for solubility calculated using Advanced Chemistry Development (ACD) Software Solaris V4.67. These semi-quantitative ranges for molar solubility are very soluble, 1 mol L 1 < solubility soluble, 0.1 mol L 1 < solubility < 1 mol L 1 slightly soluble, 0.01 mol L 1 <... 

Advanced Chemistry Development Inc. has built a sizeable proton chemical shift database derived from published spectra (most commonly in CDCI3 solution). Their H NMR predictor programme accesses this database and allows the prediction of chemical shifts. Whilst this software takes account of geometry in calculating scalar couplings, in predicting chemical shifts it essentially treats the structure as planar. It would therefore seem doomed to failure. However, if closely related compounds, run at infinite dilution and in the same solvent, are present in the database, the conformation is implied and the results can be quite accurate. Of course, the results will not be reliable if sub-structures are not well represented within the database and the wide dispersion of errors (dependent on whether a compound is represented or not) can cause serious problems in structure confirmation (later). ACD are currently revising their strict adherence to HOSE codes for sub-structure identification and this will hopefully remove infrequent odd sub-structure selections made currently. 

Log KoW, MP, and Kp values were calculated with the Syracuse Research Corporation (SRC, Syracuse, NY) KOWWIN, MPBPWIN, and DERMWIN software packages (SRC, Syracuse, NY, USA), respectively, using the SMILES codes of the chemicals as the input. Values of MW and ST were calculated with the Advanced Chemistry Development (ACD) ChemSketch software. 

We thank Anthony Williams, Vice President and Chief Science Officer of Advanced Chemistry Development (ACD), for donating software for IR/MS processing, which was used in four of the eight chapters it allowed us to present the data easily and in high quality. We also thank Paul Cope from Bruker BioSpin Corporation for donating NMR processing software. Without these software packages, the presentation of this book would not have been possible. 

In addition to the published literature, a chemical shift database is being developed by Advanced Chemistry Development (AC D/Labs) that can be used interactively by an investigator both to predict chemical shifts for a molecule being investigated and to search the database by a multitude of parameters, including structure, substructure, and alphanumeric text values. This database is accessible in the NNMR software package offered by ACD/Labs and presently contains data on more than 8800 compounds with over 20 700 chemical shifts. Examples of the use of the NNMR database will be presented later in this chapter. 

Substance identifier no. 18039-42-4,SciFinder Scholar (2006), Calculated using advanced chemistry development (ACD/Labs) software V8.14 for Solaris (1994-2006 ACD/Labs). 

The log P, log D al pH 7, and pK values are from Chemical Absiracis Service. American Chemical Society, Columbus. OH. 2003, and were calculated by using Advanced Chemistry Development (ACD) Software Solaris V4.67. The pK v ues are for the most acidic HA acid and most weakly acidic BH groups. The latter represent the most basic nitrogen. Keep in mind that pK, values for HA acids that exceed 10 to 11 mean that there will be little, if any, anionic contri-... 

ACD/H-NMR from Advanced Chemistry Development (ACD) Labs calculates H-NMR spectra under any basic frequency. The system uses 3D molecular structure minimization and Karplus relationships to predict proton-proton coupling constants. The software recognizes spectral differences among diastereotopic protons, cis-trans isomers of alkenes, syn-anti isomers of amides, oximes, hydrazones, and nitrosa-mines. The base data set includes more than 1,000,000 experimental chemical shifts and 250,000 experimental coupling constants. To quantify intramolecular interactions in new organic structures and to predict their chemical shifts, ACD/HNMR uses an algorithm based on intramolecular interaction parameters to quantify intramolecular interactions in new organic structures and to predict their chemical shifts. 

An estimate for the differences in basicity between the pyridyl and the benzimidazol-l-yl moieties were obtained by calculating pKa values for the conjugated acids of the two hydrogen-bond acceptors in each SR. 3-(benzimi-dazol-l-yl)methylpyridine pKa = 4.71 + 0.10 and 5.72 +0.30 for pyridyl and benzimidazol-l-yl moieties, respectively. 3-(2-methylbenzimidazol-l-yl)mefhyl-pyridine pKa = 4.72 +0.10 and 5.85 + 0.18 for pyridyl and benzimidazol-l-yl moieties, respectively. Calculations were performed using Advanced Chemistry Development (ACD/Labs) Software Solaris V4.76 ( 1994-2005 ACD/Labs). 

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