General reactions with hydroxyl group



Here we shall consider 3-tropanol as a standard compound.

01. Upon oxidation with cromic acid tropine first forms Tropinone. 

The reaction further proceeds to give ecgoninic acid or N-methyl succinimide. 

With halogens oxidation occurs yielding 2,2,4,4-tetrahalo Tropinone. 

Tropine burns in air. 


02. Sodium or potassium reacts upon Tropine forming tropoxide. 

The product is stronger base than water. Hence it is not stable in water.

Strong bases such as metal hydrides or metal amides also react with Tropine to give tropoxide. 


03. Tropine reacts upon Grignard reagents giving alkane.

04.It reacts with carboxylic acids in presence of mineral acids to produce esters. 

Acid anhydrides can be used for better yield. 

Acyl halides give the best yield with a vigorous reaction. 


05. With Lucas reagent it gives tropnyl halides. 

It also reacts with phosphorus halides or thionyl halides giving tropyl halides. Thionyl chloride should be used for a clear product since SO2 and HCl are both gases. 


For 3-bromo tropane, HBr + conc. sulfuric acid is used, and for 3-iodo tropane simply HI is refluxed with tropine.


06.  Tropine reacts with aldehydes or ketones in presence of dry HCl to form acetals or ketals. 

It reacts with acetylene in presence of Hg compounds to yield acetals. 

07. Phosgene reacts with Tropine in an inert solvent (e.g. benzene) at low temperature to yield tropyl chloroformate. 

When phosgene is heated with excess of Tropine in presence of pyridine, the product is tropyl carbonate. 

08. Tropine can be methylated (also alkylated) by dimethyl sulphate or dimethyl carbonate. 

09. HNO3 and H2SO4 react with Tropine to produce tropanyl nitrate and tropanyl bisulphate. 

The bisulphate compounds thus produced reacts further to give a variety of products upon reaction conditions.

 

a. When heated alone 

b. When H2SO4 in excess 

c. When Tropine in excess 

10. Tropine combine with phenylisocyanate to form N-Phenyl substituted urethan. 

These types of compounds are crystalline solids and may be used to characterize Tropine, Scopine or other hydroxy Tropane.

 

11. On exhaustive methylation it yields tropilidene (cyclohepttriene). 

12. By action of conc. Nitric acid at low temperature tropanyl nitrate is formed. 

 

Urea is added to destroy any nitrous acid formed.

 

13. By the action of nitrous acid on tropine, tropanyl nitrate is formed. 

 

14. In presence of Lewis acids diazomethane reacts with tropine. 

 

15. Tropanyl borates are prepared by the reaction of tropine with boric acid. 

 

Tropanyl phosphates are obtained by the reaction of phosphorus oxychlorides in pyridine.