Reaction classification has important applications, and many approaches to classification have been applied. Our own algorithm tests all maximum common substructures (MCS) between all reactant and product molecules in order to find an atom mapping containing the minimum chemical distance (MCD). Recent publications have concluded that new MCS algorithms need to be compared with existing methods in a reproducible environment, preferably on a generalized test set, yet the number of test sets available is small, and they are not truly representative of the range of reactions that occur in real reaction databases. We have designed a challenging test set of reactions and are making it publicly available and usable with InfoChem's software or other classification algorithms. We supply a representative set of example reactions, grouped into different levels of difficulty, from a large number of reaction databases that chemists actually encounter in practice, in order to demonstrate the basic requirements for a mapping algorithm to detect the reaction centers in a consistent way. We invite the scientific community to contribute to the future extension and improvement of this data set, to achieve the goal of a common standard.
The Reaction InChI (RInChI) extends the idea of the InChI, which provides a unique descriptor of molecular structures, towards reactions. Prototype versions of the RInChI have been available since 2011. The first official release (RInChI-V1.00), funded by the InChI Trust, is now available for download (http://www.inchi-trust.org/downloads/). This release defines the format and generates hashed representations (RInChIKeys) suitable for database and web operations. The RInChI provides a concise description of the key data in chemical processes, and facilitates the manipulation and analysis of reaction data.
The IUPAC International Chemical Identifier (InChI) provides a method to generate a unique text descriptor of molecular structures. Building on this work, we report a process to generate a unique text descriptor for reactions, RInChI. By carefully selecting the information that is included and by ordering the data carefully, different scientists studying the same reaction should produce the same RInChI. If differences arise, these are most likely the minor layers of the InChI, and so may be readily handled. RInChI provides a concise description of the key data in a chemical reaction, and will help enable the rapid searching and analysis of reaction databases.
The Journal of Organic Chemistry terial (vpc, 200°). Upon distillation, a main cut, 94 g, bp 77°( 15 mm), n20d 1.4545, of a 91:9 isomeric mixture of 6 and 6a (vpc, 20M, 90°) was obtained.Cyclization 16 g), benzene (32 ml), and p-toluenesulfonic acid (0.5 g) were refluxed for 14 hr; upon neutralization and evaporation of the solvent, 13 g were obtained, n®d 1.4620, showing the following composition: 23% 7 and 7a; 53% 6; 9% 6a; and 15% unreacted 9. Cyclization of 9a.-cfs-2,6-Dimethyl-2,4-octadien-8-ol (9a, 15 g) and 30% H2SO< (15 ml) were vigorously agitated at room temperature (20-30°) for 22 hr. The reaction mixture, after neutralization, afforded 14 g, which showed the following composition (vpc, 20M, 90°): 1% 7 and 7a; 39% 6; 6% 6a; and 54% unreacted 9a. cis and iraros-2-(2-Methyl-2-hydroxyprop-l-yl)-4-methyltetrahydropyran (10 and 10a).-ircros-2,6-Dimethyl-2,4-octadien-8-ol (9, 100 g) was fed within 5 min, under cooling at 0-10°, into 62.5% H2S04 (100 ml); the temperature was left to reach 20-25°w ithin 5 min. The reaction product was then poured onto 30% NaOH (200 ml) under cooling (30-40°), and the top layer separated; it afforded, upon distillation, 75 g of a main cut, bp 75-80°( 2 mm), n20d 1.4480, of a 95:5 cis-trans mixture of hydroxyrosoxide (10 and 10a) (vpc, 190°).Conversion of 10 into a Mixture of Rosoxides 6 and 6a.-Hydroxyrosoxide 10 (100 g), benzene (400 ml), and concentrated H2SO< (4 g) were heated under reflux for 1 hr (80-82°) while water was azeotroped off in a Dean-Stark trap. The mixture, after neutralization and distillation, afforded 70 g, n®d 1.4550, consisting of 30% 7, 2% 7a, 64% 6, and 4% 6a (vpc, CW 20M, 90°); cf. ref 4. m-Rosoxide [ró-2-(2-methyl-l-propen-l-yl)-4-methyltetrahydropyran, 6], separated by distillation through a Nester-Faust Teflon spinning-band column, gave the following data: bp 86°( 20 mm); n20d 1.4535.The nmr spectrum follows: H at Ci, d, fine splitting, 5.09,
The structures of the by-products in thc demethylation were determined by the use of nmr. ment (5 -+ 6 ) and the preferential 0-demethylation of 6, is described. and mass spectroscopy.Vor kurzem [2] berichteten wir uber eine einfache Darstellung von l-Benzyl-2-methy1-lI2,3,4-tetrahydro-isochinolinen durch Stevens-Umlagerung der entsprechenden 2-Benzyl-2-methyl-1, 2, 3,4-tetrahydro-isochinolinium-Salze. Gleichzeitig war es uns im Zusammenhang mit Arbeiten uber selektive Atherspaltungen in der Isochinolinreihe gelungen, die 8-Methoxygruppe in 7,8-L)imethoxy-l, 2,3,4-tetrahydro-isochinolinen bevorzugt zu spalten (11. Eine Kombination dieser beiden Befunde fuhrte Schema I
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