Salts hydrochloride

Preheat a water bath on the stove (or wherever) to about 80C and place the stainless steel mixing bowl in it. Once the temperature of the solution hits about 65C, take the bowl out and set aside while stirring all the while. This is where it rearranges, and the reaction is exothermic enough to sustain it s temperature nicely. If you find the temperature climbing past 80C, immerse the bowl into some cold waiter briefly. After about 15 minutes the temperature will start to fall, at which point you should transfer the whole mess to the distilling flask. Before you continue you need to choose whether you want to make the hydrochloride salt or the aqueous solution of Methylamine, though. 

Fluoropyridine. This isomer can be prepared in 54—81% yield by dia2oti2ation of 4-aminopyridine in anhydrous hydrogen fluoride (370,371,400). Eree 4-fluoropyridine readily undergoes self-quaterni2ation to give pyridyl pyridinium salts (401) stabili2ation can be effected as the hydrochloride salt (371,400). Numerous 4-fluoropyridinium salts, eg, 4-fluoro-l-methylpyridinium iodide, have been converted to novel penicillins (387,402). 

Trifluoromethylpyridine can be prepared ia 54% yield from picolinic acid and sulfur tetrafluoride—hydrogen fluoride (434). 2-Trifluoromethylpyridine is a weak base no hydrochloride salt is formed. However, 2-trifluoromethylpyridine 1-oxide [22253-71-0] (bp 132—133°C/2.7 kPa (20 mm Hg)) is prepared ia 81% yield usiag 30% hydrogen peroxide—acetic acid (438). 

AH of the toxicity data on MDA have been collected using either 4,4 -MDA or the corresponding hydrochloride salt. The information discussed in this section can also be used for commercial products containing MDA or PMDA. Because MDA is a potentially ha2ardous chemical, worker exposure should be kept to a minimum. For complete health and safety information on MDA consult references 46 and 56—59. 

Amino-4,6-dichlorophenol. This compound (11) forms long white needles from carbon disulfide, and aggregate spheres from benzene. It sublimes at 70—80°C (8 Pa = 0.06 mm Hg) and decomposes above 109 °C. It is freely soluble in benzene and carbon disulfide, and is sparingly soluble in petroleum ether, water, and ethanol. The free base is unstable and the hydrochloride salt (mp 280—285°C, dec) is employed commercially. 

V,/V-dimethy1amino)pheno1 (177). In addition, 3-aminophenol may be methylated with dimethyl sulfate under neutral conditions, or its hydrochloride salt heated with methanol at 170°C under pressure for 8 h to give the desired product (178). The compound is used primarily as an intermediate in the production of basic (Red 3 and Red 11) and mordant (Red 77) dyes. 

Amino-2-hydroxybenZOiC acid. This derivative (18) more commonly known as 4-aminosa1icy1ic acid, forms white crystals from ethanol, melts with effervescence and darkens on exposure to light and air. A reddish-brown crystalline powder is obtained on recrystallization from ethanol —diethyl ether. The compound is soluble ia dilute solutioas of nitric acid and sodium hydroxide, ethanol, and acetone slightly soluble in water and diethyl ether and virtually insoluble in benzene, chloroform or carbon tetrachloride. It is unstable in aqueous solution and decarboxylates to form 3-amiaophenol. Because of the instabihty of the free acid, it is usually prepared as the hydrochloride salt, mp 224 °C (dec), dissociation constant p 3.25. 

Methods (25,26) to iacrease the ratio of the desired a-isomer (1) versus the unsweet -isomer [22839-61-8] (3) exist and are proprietary. The isomers can be separated by subjecting the solution of the final step to hydrochloric acid. The desired a-isomer hydrochloride salt crystallines out of the solution the P-isomer remains. There are many patented synthetic processes. The large-scale synthesis of aspartame has been discussed (27—47). 

Levopropoxyphene [2338-37-6] (42), the optical antipode of the dextrorotatory analgetic propoxyphene, is an antitussive without analgetic activity. The 2-naphthalenesulfonate salt has a less unpleasant taste than the hydrochloride salt, and is widely used. Clinical effectiveness has been demonstrated against pathological and artificially induced cough, but the potency is somewhat less than codeine. The compound is reported not to cause addiction. Levopropoxyphene can be prepared (62) by first resolving [ -dimethylamino-CX-methylpropiophenone with dibenzoyl-(+)-tartaric acid. The resolved... 

An alternative approach to the use of a-aminoketones involves acetals (72JOC221) and pyrazine-2,3-diones have been synthesized by this route (Scheme 58). The acetals are readily available from the phthalimido derivatives via the a-chloroketones. Hemiacetals have also served as a starting point for pyrazine synthesis, although in most cases hemiacetals are too labile to be easily prepared examples are common in the 2-amino-2-deoxy sugar series 2-amino-2-deoxy-D-glucose for example dimerizes to the pyrazine (101) when generated in situ from the hydrochloride salt (68JAP6813469). 

Dissociation extraction is the process of using chemical reac tion to force a solute to transfer from one liquid phase to another. One example is the use of a sodium hydroxide solution to extract phenolics, acids, or mercaptans from a hydrocarbon stream. The opposite transfer can be forced by adding an acid to a sodium phenate stream to spring the phenolic back to a free phenol that can be extrac ted into an organic solvent. Similarly, primary, secondary, and tertiary amines can be protonated with a strong acid to transfer the amine into a water solution, for example, as an amine hydrochloride salt. Conversely, a strong base can be added to convert the amine salt back to free base, which can be extracted into a solvent. This procedure is quite common in pharmaceutical production. 

Acetylcholine bromide [66-23-9] M 226.1, m 143 , 146 . Hygroscopic solid but less than the hydrochloride salt. It crystd from EtOH as prisms. Some hydrolysis occurs in boiling EtOH particularly if it contains some H2O. It can also be recryst from EtOH or MeOH by adding dry Et20. [Acta Chem Scand 12 1492, 1497, 1502 1958.]... 

Cocarboxylase tetrahydrate (aneurine pyrophosphoric acid tetrahydrate, thiamine pyrophosphoric acid tetrahydrate) [136-09-4] M 496.4, m 220-222°(sinters at 130-140°), 213-214°, pKes,(1)-2, pKeskd O pKesi(3) 9- Recrystd from aqueous Me2CO. [Wenz et al. Justus Liebigs Ann Chem 618 210 7955 UV Melnick J Biol Chem 131 615 1939 X-ray Carlisle and Cook Acta Cryst (B) 25 1359 1969.] The hydrochloride salt has m 242-244°(dec), 241-243°(dec) or 239-240°(dec) and is... 

The hydrochloride salt is dissolved in 100 ml of methanol and 110 ml of 15% ammonium hydroxide is added in several portions. The mixture is cooled and the crystalline product is filtered and washed with methanol-water (1 1). The dried 3f5-hydroxy-16o -methoxylaminopregn-5-en-20-one acetate (114) obtained in ca. 90% yield is recrystallized from acetone mp 147-149°. 

This acylation might still be assumed to proceed via the aminocyclobutanone with subsequent rearrangement, but it was shown (75) that the hydrochloride salt of the aminocyclobutanone (101), prepared by an alternate method, was not rearranged under the reaction conditions. The intermediacy of (101)... 

The Kepmter modification is when the hydrochloride salt of 1 is used as the... 

Table V. UV Spectra oe Coralyne-13-Olate 109, its Hydrochloride Salt 109 HCl, AND ITS Methoxy Derivative 112...

The 2-amino-selenazoles are crystalline compounds, and sometimes unstable, for example, the parent compound on heating in water undergoes complete decomposition. A few of these selenazoles which are substituted in the amino group are oily liquids. The basic character is more pronounced than in the alkyl- and aryl-selenazoles. The hydrochloride salts are, therefore, not so easily hydrolyzed in aqueous solution. 2-Amino- and 2-methylamino-4-methylselenazole have been considered to exist partly in the tautomeric selenazol-2-one imine form from comparison of their ultraviolet spectrum with that of 2-diethylamino-4-methylselenazole. ... 

A solution of 24.6 g of o-allyl-epoxypropoxybenzene dissolved in 250 ml of absolute ethanol saturated with ammonia was placed in an autoclave and heated on a steam-bath for 2 hours. The alcohol was then removed by distillation and the residue was redissolved in a mixture of methanol and ethylacetate. Hydrogen chloride gas was introduced into the solution. The hydrochloride salt was then precipitated by the addition of ether to yield 11.4 g of product. Five grams of the amine-hydrochloride thus formed were dissolved in 50 ml of methanol and 9 ml of acetone. The resulting solution was cooled to about 0°C. At this temperature 5 g of sodium borohydride were added over a period of 1 hour. Another 2.2 ml of acetone and O.B g of sodium borohydride were added and the solution was kept at room temperature for 1 hour, after which 150 ml of water were added to the solution. The solution was then extracted with three 100-ml portions of ether which were combined, dried over potassium carbonate, and evaporated. The free base was then recrystallized from petrol ether (boiling range 40°-60°C) to yield 2.7 g of material having a melting point of 57°C. 

The corresponding hydrochloride was prepared by dissolving 2 g of the product, prepared above, in 20 ml of acetone, and adding to the resulting solution acetone saturated with hydrogen chloride until the pH was reduced to about 3. The precipitated hydrochloride salt was then recrystallized from acetone. 

To produce the hydrochloride, the base is suspended in water (70 ml) and treated with sufficient 6 N hydrochloric acid to dissolve the free base. The solution is filtered and treated with concentrated hydrochloric acid (5 ml). The hydrochloride salt (2.2 g, 97%) separates and Is recrystallized from water (50 ml) containing concentratad hydrochloric acid (3 ml). 

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