Levo isomer

The free base of either optical isomer may be obtained by addition to the d-tartrate in the case of the levo isomer and the d-bitartrate in the case of the dextro isomer of alkali in excess, as, for example, by the addition of an aqueous solution of caustic soda, which will cause the base to separate as an oil which may be recovered and purified by any well-known procedure. The base is exactly neutralized with sulfuric acid to give the sulfate. 

They rotate the plane of polarized light in opposite directions, though in equal amounts. The isomer that rotates the plane to the left (counterclockwise) is called the levo isomer and is designated ( —), while the one that rotates the plane to the right (clockwise) is called the dextro isomer and is designated (-t-). Because they differ in this property they are often called optical antipodes. 

Using the PCP rating scale for stereotyped behavior and ataxia as described by Sturgeon et al. (1979), the central effects of PCP analogs, dexoxadrol, and its levo-isomer, levoxadrol, were determined. As shown in figure 1, all drugs except the (-) isomers produced dose-dependent stereotyped behavior. In contrast,... 

Levofloxacin (1), the levo-isomer or the (5)-enantiomer of ofloxacin, received FDA approval in 1996 (Fish, 2003 Hurst et al., 2002 Mascaretti, 2003 Norrby, 1999 North et al., 1998). The initial approval covered community-acquired pneumonia, acute bacterial exacerbation of chronic bronchitis, acute maxillary sinusitis, uncomplicated skin and skin structure infections, acute pyelonephritis, and complicated urinary tract infections (North et al., 1998). Four years later, the levofloxacin indication list grew to include community-acquired pneumonia caused by penicillin-resistant Streptococcus pneumoniae. In addition, in 2002, nosocomial (hospital-acquired) pneumonia caused by methicillin-susceptible Staphylococcus aureus, Pseudomonas aeruginosa, Serratia marcescens, Haemophilus influenzae, Kliebsella pneumoniae, and Escherichia coli was added (Hurst et al., 2002). Finally in 2004, LVX was approved as a post-exposure treatment for individuals exposed to Bacillus anthracis, the microbe that causes anthrax, via inhalation (FDA, 2004). 

Hyoscyamine is a tertiary amine. It is the levo-isomer to atropine. Tetertiary amines have the potential to cross the bloodbrain barrier and their oral absorption is also considerably better. Other synthetic tertiary amines used for their antispasmodic properties are dicyclomine and phencyclimine. 

Chemical Class Synthetic levo isomer of fhyroxine (T4)... 

The racemic DL-tetramisole and its levo-isomer, levamisole, constitute the best-known members within this group of drugs (Fig. 4.2). Since the anthelminthic activity of tetramisole, which was first marketed in 1966, resides almost entirely in its levo-isomer, levamisole rather than the parent tetramisole is the drug currently used in most countries. 

Drug absorption from the oral cavity occurs through the passive diffusion of the nonionized form from an aqueous phase to one that is lipid in nature. In addition, there is also evidence for the carrier-mediated transport of drugs, whereby the levo isomers, but not the dextro isomers, of many drugs are absorbed. 

A levo-isomer of a compound selected from the class consisting of 1-cyclohexyl-1 -phenyl-3 -piperidinopropan-1 -ol and 1 -cyclohexyl-1 -phenyl-3 -... 

The myo, the dextro, and the levo isomers of inositol are readily obtainable from natural sources, whilst the other diastereomers are usually synthesized from these compounds by a series of reactions which amount to epimerizations at one or more centers. These syntheses will be discussed under the individual inositols the present Section deals only with syntheses of inositols from non-cyclitol materials. 

A very similar elaboration of the levo isomer (-)-263 (Scheme 54) has been reported by Theil, von Janta-Lipinski, and co-workers (94TL1961 95T761). Thus, the reaction of (-)-263 with 6-chloropurine 270 under Pd(0) catalysis gave 271, featuring the unusual stereochemistry characteristic of this type of carbanucleoside then 271 was converted into the homo-... 

Spring Grove researchers of Turek, Soskin and Kurland studied ten subjects given 70 mg. of the levo-isomer orally and observed a drop in blood pressure "followed by a rise during the second and third hours after administration, returning to the pre-drug pressure at the fifth hour. MDA also induces sleeplessness in some people, although not as often or severely as equivalent amounts of amphetamine. 

Few studies have been published about MDA s effects. I.S. Turek, R.A. Soskin and Albert Kurland report on one in Vol. 6, No. 1 of the Journal of Psychedelic Drugs, in which they describe the subjective effects of 70 mg. of the MDA levo-isomer taken orally by ten subjects, nine of whom had experienced LSD in a similarly controlled setting. Their findings concur with other available reports they emphasize that, compared to LSD, this compound produces fewer "intuitive experiences involving a sense of ego loss and "less transcendence of time or space but more verbal communication. 

It is remarkable that, for histamine, very few compounds of plant origin have been found to have JI (or H2, H3, H4) -blocking properties (Fig. 18.17). a-Mangostin [28] is an example, although remarkably this compound (a competitive H, antagonist) does not carry a basic function. A basic tertiary amino group is also absent in cicletanide, an intriguing compound that has a chiral center and in which the antihistaminic activity resides in the levo isomer (Fig. 18.17). Rocastine and temelastine are two other antihistaminic compounds with unusual structures (Fig. 18.12). 

After alcohol, lactic acid was the second product obtained industrially from sugar fermentation, starting in 1880. The levo-isomer is still made this way to the tune of 20,000 tons a year. 

This amine is of interest because it is readily resolved with tartaric acid to give the pure dextro and levo isomers.1... 

Naloxone, prepared in eight steps from (+)-7-bromodihy-drocodeinone dimethyl ketal (26% overall yield), proved virtually inactive in three test systems (binding, GPI, and neuroblastoma x glioma hybrid cell adenylate cyclase assays) and can thus be used to establish the stereospecific binding of the natural levo isomer.(37) Both antipodes of naloxone are available from a total synthesis of morphinans starting from optically active 1-benzyl-isoquinolines.(128)... 

Levobunolol is suppUed as a 0.25% and 0.5% sterile ophthalmic solution of the levo-isomer of the hydrochloride salt.The formulation contains a viscosity agent, 1.4% polyvinyl alcohol, and is preserved with BAG 0.004% (see Table 10-1). 

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