Preparation of Evidence in Illicit Amphetamine Manufacturing Prosecutions

Preparation of Evidence in Illicit Amphetamine Manufacturing Prosecutions CECIL L. H I D E R Criminalist, S a n Mateo County Sheriff's Dept., Redwood City, California

A discussion of the technique utilized in the illicit manufacture of amphetamine i s presented. T h e chemical precursors and catalytic agents which m a y be encountered are described. Due to the nature of the material, it i s suggested that the laboratory staff be directly responsible for the collection, preservation, and presentation of evidence seized in investigations of illicit amphetamine production. During the years 1962-1963, the abuse of adrenergic or sympathomimetic amines, and d-methylamphetamine in particular, reached an all time high in California. This was in part due to its clandestine availability from some doctors and pharmacists in the State. In 1964, newly enacted State statutes, coupled with withdrawal of the compound from all but hospital use by one of the leading manufacturers, led to the first illicit processing of the drug. The first illicit processing in California was apparently by a few individuals who procured the pure drug in salt form from the Eastern portion of the United States. The drug was then dissolved in water and packaged in vials, similar in appearance to the product marketed by the leading licit manufacturer. In 1966, Federal laws regulating certain restricted drugs, including the amphetamines, rendered it virtually impossible for the illicit processor to obtain the drug. By late 1966 and early 1967, much evidence of the illicit synthesis of amphetamine was apparent. The most popular drug manufactured illicitly appears to be methylamphetamine. The most common chemical precursors used in illicit manufacturing are methylamine and phenyl-2-propanone (phenylacetone). Precursor chemicals often will be found in bottles labelled as such, or as by-products from the completed synthesis. The completed amphetamine product will normally appear as a wine-red liquid, ye!low ethereal solution, or granular light brown powder. On rare occasions the manufacturer will utilize activated charcoal to produce a white product which is difficult or impossible to distinguish from legitimate sources. I t is frequently observed that an illicit manufacturer, unsure of his results by any given method, will acquire supplies for more than one method. Many chemical supply houses will now notify authorities if amphetamine precursors are ordered or purchased, although possession of these materials does not violate California or Federal laws. Cheap, superfluous chemicals are often ordered in order t o avoid detection. The practice of illicit amphetamine manufacturing has become prevalent in several areas. This is in part due to the fact that the cookbook-like procedures have been passed from hand t o hand, thereby providing many persons with an ability to manufacture these drugs without actually possessing a detailed knowledge of chemical principles. The most apparent feature noted by the analyst or investigator a t the scene of an illicit laboratory will be the odor of diethyl ether or other solvents. The equipment being utilized and the precursors will generally indicate whether amphetamine or methylamphetamine is being manufactured. Precursors which may be encountered, other than methylamine and phenylacetone, would include ephedrine, benzylcyanide, and phenylacetic acid. Diverse catalytic agents have been encountered in the illicit manufacture of amphetamine and methylamphetamine. The most commonly employed catalysts, however, are salts of nickel, platinum, and palladium. One may occasionally expect to encounter thionyl chloride as well as salts of cobalt, 75

copper, and chromium serving as catalysts. The most common reducing agent encountered is hydrogen, although several metals, such as sodium, are easily employed. In many instances the chemical precursors are not found, as illicit operators often purchase only those amounts of chemicals necessary for one synthesis. The precursors and other reactants may still be isolated, however, from the finished amphetamine product or mother solutions. I n view of the nature of the evidence in these cases, it is recommended that the analyst personally collect or supervise the collection of evidence. The following mechanisms depict the most common methods encountered in cases involving illicit amphetamine manufacture :

Method 1

Phenylacetone

Methylamine

Methylamphetamine

This method involves reduction of a mixture of phenylacetone and aqueous methylamine in ether. The reduction is accomplished by using hydrogen with salt of palladium as the catalyst.

Phenylacetone

Methylamine

blethylamphetamine

In this method, the condensation products of phenylacetone and methylamine are reduced by sodium metal in the presence of ethyl alcohol, and requires approximately four weeks to react. Initially, ethyl alcohol, methylamine, and phenylacetone are left at room temperature in a stoppered bottle and allowed to react for approximately four weeks. Sodium metal, together with an excess of ethyl alcohol, is added to this mixture for reduction. After reduction, water is added, the ethyl alcohol evaporated, and the resultant solution steam distilled until the mother solution is no longer alkaline. Hydrochloric acid is used for neutralization, and the insoluble portion is then extracted with ether. The extract is condensed and precipitated with mercuric chloride. The mercury salt is decomposed wit11 hydrogen sulfide, leaving the free base of methylamphetamine.

Ephedrine

hle thylamphetarnine

111 the third method, the catalytic hydrogenation of ephedrine is performed in acetic acid containing a, small quantity of perchloric acid as an activator. The hydrogenation is carried out between 80 and 90°C using palladium black as the catalyst. Perchloric acid is removed as the insoluble potassium salt. The product is distilled under reduced pressure to remove acetic acid. To the aqueous solution of the residue is added an etheral solution of hydrochloric acid to precipitate methylamphetamine.

Method

4

0'

\ / CHgirH3 Ephedrine

+

SOCl2 CH3

Thionyl chloride

-

Catalyst

Qcr2cxmcH3 I CH3

In this synthesis, the replacement of the hydroxyl group of ephedrine by the halogen atom is accomplished through the use of thionyl chloride. The catalytic hydrogenation of the newly formed intermediate products yields methylamphetamine.

Method

5

Phenylacetic acid

Acetic acid

Phenylacet one

Fomamide Formic acid

This method involves the thermal acetylation and decarboxylation of phenylThe phenylacetone is then subjected to the acetic acid to phenylacetone. Leuckart reaction, a reductive amination with formamide, formic acid, and ammonium formate. The derivative from this reaction is hydrolyzed with strong acid to yield amphetamine. 77

Method

6

Phenylacetone

Amphetamine

The sixth synthesis employs the reductive amination of phenylacetone in the presence of nickel catalyst and ammonia under pressure to deliver amphetamine.

Method 7 ~ C % C O O H

+

Phenylacetic a c i d

Hydroxylamine

-0

( C H ~ C O ~ ) ~ ~ NaOAc 145-150°C Acetic anhydride

Oxime of phenylacetone

C%COCH~

Phenylacetone

Amphetamine

I n this synthesis, phenylacetic acid is reacted with acetic anhydride and sodium acetate between 145 and 150°C to prepare phenylacetone. Phenylacetone is then converted to its oxime by its reaction with hydroxylamine. The oxime is then reduced to amphetamine.

hde thod 8

-

EtOAc

H2S04

Benz y l c y a n i d e

Phenylcyano acetone

Phenylacetone

Amphetamine

In this method, phenylacetone is prepared from benzylcyanide and ethyl acetate in the presence of sodium alcoholate, through the intermediate formation of phenylcyanoacetone. The phenylcyanoacetone is hydrolyzed by dilute sulfuric acid t o phenylacetone, which is then converted to amphetamine by methods outlined above. 78

I t is apparent from the several methods and many reductive-catalytic systems that the chemicals and apparatus found a t any given illicit laboratory site may vary to a considerable extent. Once the method or methods of preparation has been determined it will be necessary to insure by analysis that the yield product was in fact prepared by that method for purposes of court testimony. Many analytical techniques are available for the analysis. The presence of primary or secondary amines may be determined, a separation of primary and secondary amines may be effected through the use of the Hinsberg test, and catalyst, precursors, and by-products identified. Final identification may be accomplished by use of one or more tests which may involve microchemical tests, infrared spectroscopy, gas or thin layer chromatography, and refractometry. In order to insure the thoroughness of preparation of the case for court purposes, and in consideration of the technical nature of the evidence which may be encountered, it is suggested that the responsibility for the collection, preservation, and court presentation of evidence in illicit manufacturing of amphetamine cases should rest with the laboratory staff.

References AUGUSTINE, ROBERTL., 1965, Catalytic Hydrogenation, Marcel Dekker, New York. BURGER, ALFRED,1960, Medicinal Chemistry, 2nd Edition, Inter-science, New York. CALDWELL, D., and NORMAN EVERS,1959, The Chemistry of Drugs, 3rd Edition, Interscience, New York. MARTIN,ERIC W., et al, 1965, Remington's Pharmaceutical Sciences, 13th Edition, Mack Publishing Co., Easton, Pa.