Dextromethorphan, structure

DEPT-NMR spectrum. 6-methyl-5-hepten-2-ol, 451 Detergent, structure of, 1065 Deuterium isotope effect, 386-387 El reaction and, 392 E2 reaction and, 386-387 Dewar benzene. 1201 Dextromethorphan, structure of, 294 Dextrorotatory, 295 Dextrose, structure of. 973 Dialkylamine, pKa of, 852 Diastereomers, 302-303 kinds of, 310-311 Diastereotopic (NMR), 456... 

FIG. 22 Chemical structures of (a) dextromethorphan hydrobromide, (b) papaverine hydrochloride, (c) quinine hydrochloride, and (d) berberine chloride. 

The most known narcotics are the opium alkaloids such as morphine, codeine, thebaine, papaverine, noscapine and their derivatives and modified compounds such as nalmorphine, apomorphine, apomopholcodine, dihydrocodeine, hydro-morphone and heroine, also known as diamorphine. Synthetic narcotics share the structural skeleton of morphine and include dextromethorphan, pentazocine, phenazocine meperidine (pethidine), phentanyl, anfentaitil, remifentalin, methadone, dextropropoxyphene, levoproxyphene, dipipanone, dextromoramide, meptazinol and tramadol. Thebaine derivatives are also modified narcotics and include oxycodone, oxymorphone, etorphine, buprenorphine, nalbuphine, naloxone or naltrexone. Narcotics can be semi-synthesized or totally synthesized from the morphine and thebaine model. The compounds serve various purposes in clinical practise. 

X 10 ml of chloroform. The chloroform layers are combined and evaporated to dryness using a rotary evaporator. The residue is dissolved in ca 10 ml of methanol and transferred to a 100 ml volumetric flask and then diluted to volume with mobile phase. The areas of the peaks obtained from the linctus extract are compared with a solution containing pseudoephedrine.HCl, dextromethorphan.HBr and triprolidine.HCl (structures shown in Fig. 11.14) at the same concentrations as would be expected in the linctus extract. 

The biological consequences of molecular shape can be dramatic. Look at the structures of dextromethorphan and levomethorphan, for instance. (The Latin prefixes dextro- and levo- mean "right" and "left," respectively.) Dextromethorphan is a common cough suppressant found in many over-the-counter cold medicines, but its mirror-image, levomethorphan, is a powerful narcotic pain-reliever similar in its effects to morphine. The two substances are chemically identical except for their shapes, yet their biological properties are completely different. 

Nonnarcotic Antitussives. The most centrally active, nonnarcotic antitussive is dextromethorphan [125-71-5] (39). It is similar to codeine in terms of potency and mechanism of action, ie, it is a direct depressant of the cough center. It is unique in that even though it is structurally related to codeine, it is not addictive. 

Fig. 10.1 Chemical structures of NMDA and AMPA antagonists used for the treatment of ischemic injury in animal models. PCP (a) MK-801 (b) Dextrorphan (c) and Dextromethorphan (d)...

Fig. 3.1 Morphine 1 has been the lead structure for the development of the major analgesic fentanyl 2, the antitussive drug dextromethorphan 3, the constipating drug loperamide 4, and the neuroleptic drug haloperidol 5.

Figure 2.3 Dextromethorphan 6, the unnatural enantiomer of a narcotic morphine analog, is an antitussive drug. The antidiarrhea drug loperamide 7 and the neuroleptic drug haloperidol 8 also resulted from structural modification of morphine. The morphine antagonist nalorphine 9 differs from the opioid agonist morphine 3 (Figure 2.2) only by having an N-allyl group instead of the N-methyl group.

Synonyms DM Dextromethorphan hydrobromide Demorphan 3-Methoxy- -methylmorphinan d-Methorphan Drug store wine Robowing Chemical/Pharmaceutical/Other Class The methyl ether of the dextrorotatory form of levor-phanol, an opiate analgesic Chemical Formula C18H25NO Chemical Structure ... 

Dextromethorphan is structurally related to the opioids, but it does not bind to opioid receptors at normal dose... 

Figure 11.15 Molecular structures of (a) acetaminophen (b) chlorpheniramine maleate (c) dextromethorphan ...

Figure 8.6 Structures of (a) dextromethorphan, (b) tramadol, (c) ibuprofen, (d) ketoprofen, (e) piroxicam, (f) tenoxicam, (g) naproxen, (h) indomethacin, (i) sulindac, and (j) diklofenac.

Structure. The availability of (+)-dihydrothebainone, later accomplished with better procedures (lijima et al. 1978a), made it possible to investigate several unnatural (+)-opioids as neurochemical tools (Jacquet et al. 1977, lijima et al. 1978b). It is interesting to note that sinomenine, only recently tested in an antitussive screen (Nakamura personal communication) proved superior to dextromethorphan and codeine, suggesting that antitussive agents may still be discovered in the (+)-series of mor-phinan alkaloids (Kerekes et al. in press). 

Most commonly, drugs which are administered as racemates have only one chiral centre. Levorphan and dextrorphan (based on the morphine structure) are unusual in that they have the opposite configurations at three chiral centres. Levorphan ([-] isomer 9 R, 13 R 14 R) is a narcotic analgesic which is potentially addictive whereas dextrorphan ([-L] isomer 9S, 13 S, 14S) is used as an antitussive drug in the form of its 0-methylether dextromethorphan. 

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