Dextro rotary

Camphor was originally obtained from the camphor tree Lauras eamphora in which it appeared in the optically active dextro-rotary form. Since about 1920 the racemic ( ) mixture derived from oil of turpentine has been more generally used. By fractional distillation of oil of turpentine the product pinene is obtained. By treating this with hydrochloric acid, pinene hydrochloride (also known as bomyl chloride) may be produced. This is then boiled with acetic acid to hydrolyse the material to the racemic bomeol, which on oxidation yields camphor. Camphor is a white crystalline solid (m.p. 175°C) with the structure shown in Figure 22.3. 

A mixture of 1.1 g of 2-amino-1-(4-methylmercaptophenyl)-1,3-propanediol, obtained as described above and 1.6 ml of ethyl dichloroacetate was heated on a steam bath for three hours. The resulting viscous yellow oil was dissolved in 25 ml of ethylene chloride and filtered hot with charcoal, and the filtrate was allowed to cool to about 25°C. From the filtrate there separated 0,92 g of tiny white leaflets which were collected on a filter. Recrystallization of this product, which was a dextro-rotary form of 2-dichloroacetylamino-1-(4-methylmercapto-phenyl)-1,3-propanediol from nitroethane yielded the pure product, which melted at 111.6°C to 112.6°C,... 

The specific rotations of the plane of polarized light of solutions of the so-called laevo-rotary malic acid and its sodium salt change with increasing dilation from being dextro-rotary to being laevo-rotary, as may be seen from the data of Woringer1 and of Thomsen2 in table 1. 

Addition of salts, adds and bases tend to make the laevo-rotary acid more dextro-rotary. With rising temperature, the pure add and also the solutions become more laevo-rotary. These changes cannot be due to dectrolytic dissociation, because the effect of hydrochloric acid is quite marked up to rdatively high concentrations and it would take relatively little acid to force back the dissociation of malic acid to a negligible value. Another reason is that we get a similar change with the concentration with malic ester in alcoholic solution. 

The ergot alkaloids having the properties of producing mixed crystals between the levo- and dextro-rotary form, often false conclusions have been made, so that mixtures of different products have often been considered as pure individuals. It will be seen in the following that the property of alkaloids consisting in giving isomorph crystallizations has also led to the fact that preparations from ergot have been considered as uniform compounds, whereas in truth they were mixtures of different alkaloids. 

Hexabioses.—Maltose.—Almost the sole occurrence of this sugar is in the product of the hydrolysis of starch either by the action of enzymes or by acid hydrolysis. It is not isolated but is fermented in the solution in which it is prepared. The enzyme, maltase, is usually elaborated by the same yeasts as carry on the fermentation. This enzyme converts the maltose into two equivalents of dextrose which are then directly fermentable. When isolated, maltose forms hard white crystalline masses, very similar to grape sugar. It is determinable by the facts that its solutions have some reducing power (about two-thirds that of glucose), and that its solutions are strongly dextro-rotary. 

Semmler and Bode have shown that santalol is a primary alcohol (or alcohols), hy its oxidation to santal aldehyde. According to these chemists this aldehyde hods at 152 to 155 at 10 mm., has a specific gravity 0-995 at 20, refractive index 1-51066, and is dextro-rotary. Its semicarhazone melts at 230. ... 

The leaves and young twigs of Lindera sericea, one of the Japanese Lomraoem, yield the oil own in commerce under this name. It is a dark yellow oil with a strong aromatic and balsamic odour, of specific gravity from SQO to 915, usually about 900, and faintly laevo-rotary. It has been examined by Ewasnij who states that it contains dextro-limonene, di ntene, inactive terpineol, and laevo-carvone. The oil, on account of its comparatively low price, has recently come into some favour as an aromatic. 

---