Codeine synthesis from morphine

Opium is a cmde exudate obtained from the opium poppy Papaver somniferum, and it provides several medicinally useful alkaloids. One of these is codeine, which is widely used as a moderate analgesic. Opium contains only relatively small amounts of codeine (1-2%), however, and most of the codeine for dmg use is obtained by semi-synthesis from morphine, which is the major component (12-20%) in opium. Conversion of morphine into... 

Both morphine and codeine are valuable analgesics. Morphine is extracted from opium, the dried latex of the opium poppy, and codeine is usually obtained from morphine by semi-synthesis (see Box 6.2), since the amounts in opium are rather small. Thebaine is a valuable raw material for semi-synthesis of a wide range of morphine-like drugs. 

Hydrocodone is an opium analgesic (pain reliever) and antitussive (cough suppressant). It is related in structure to other alkaloids used as drugs, such as morphine and codeine (see Section 8). It increased 20% in number of prescriptions for one year. Its synthesis from codeine is by simple reactions. 

Thebaine (Figure 6.50) differs structurally from morphine/codeine mainly by its possession of a conjugated diene ring system. It is almost devoid of analgesic activity, but may be used as a morphine antagonist. Its main value is as substrate for the semi-synthesis of other drugs (see below). 

Elad and Ginsburg(27,28) approached the synthesis from the arylcy-clohexanone, 14, according to Scheme 2.2. The key cyclization, 16 — 17 occurred during ketalization, when in addition the 4-OMe group was demethy-lated. ( )-Dihydrothebainone (13) resulted from the pathway shown and this was resolved to the (-)-antipode with (+)-tartaric acid. This constitutes a synthesis of codeine and morphine following the final stages of Scheme 2.1. 

Codeine, U5P. Codeine is an alkaloid that occurs naturally in opium, but the amount present is usually too small lu he of commercial importance. Consequently, most com-nienrial codeine is prepared from morphine by methylating Ihe phenolie hydroxyl group. The mcthylation methods make use of reagents such as diazonicthane. dimethyl sulfate, and methyl iodide. Newer methods arc ha.scd on its synthesis from thebaine, which makes it possible to use Papaver brac-lealum as a natural source (see above). 

Since no cost-efficient synthesis of morphine and codeine has been developed, these alkaloids are isolated from poppy straw , which consists of the entire plant tops (Dewick, 2002), and... 

Morphine (10) and codeine (11), constituents of opium, are the most interesting alkaloids found in nature. Morphine is also the oldest alkaloid isolated, in 1805, by the German pharmacist Sertiimer from opium, the sun dried latex of Papaver somniferum. The structure of morphine with its so-called morphinan skeleton, once called the acrobat under the alkaloids, was finally elucidated in 1952 by the first total synthesis performed by Gates and Tschudi. Many syntheses would follow [26], but all morphine used today, whether legal or illicit, originates in the natural source P. somniferum or its extract, opium. The latex may contain up to 20% morphine. Most legal morphine is converted into the anticough medicine codeine (Table 5.1) by treatment with trimethylanilinium methoxide, whereas almost all illicit morphine is acetylated to the diacetate heroin. 

Oxycodone The synthesis of oxycodone, 4,5-epoxy-3-methoxy-14-hydroxy-iV-methyl-6-oxomorphinane (3.1.25), from 14-hydroxycodeinone (3.1.24) was described above. It can also be synthesized in other ways for example, by the oxidation of codeine using sodium dichromate in acetic acid [17], and is also a stractural analog of morphine and codeine. 

In 1803 the German pharmacist Seturner achieved the isolation of morphine as one of the active ingredients of opium. He named the compound after Morpheus, Ovid s god of dreams, the son of sleep. Among the other alkaloids of opium are codeine, isolated in 1832, thebaine, narceine, narcotine, and papaverine. From the isolation of pure morphine to the elucidation of its structure by first Gulland and Robinson(1,2) and later Schopf(3) took another 120 years. A total synthesis by Gates and Tschudi(4,5) confirmed the structure in the early 1950s. 

Synthesis of thebaine and oripavine from codeine and morphine Barber, Randy B. Rapoport, Henry... 

Morphine s synthesis remains a serious challenge to this day. Until recently, the formal synthesis published by Kenner Rice [16] was its most efficient preparation. In 2009, Magnus reported a route to codeine with a reported overall yield of approximately 17% [17]. All academic s)mtheses reported in the literature, creative as these may be, suffer from lack of practicality, with the sole exception of Rice s disclosure, which has potential for scale-up. 

Another possibility for practical synthesis could come from the combination of fermentation for attaining specific steps with semisynthesis to complete the preparation. Currently, we are fully dependent on natural sources of morphine and all medicinally useful derivatives are made by semisynthesis. Perhaps more important goals for the future generations of chemists would be to focus on the de novo total synthesis of the derivatives themselves rather than morphine or codeine. Perhaps we will see some effort devoted to this most worthwhile task in the near future. 

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