Bases hydrochlorides

In glacial acetic acid (an acidic solvent) and in dioxane (a neutral solvent), the perchloric acid (HC104) behaves as more acidic (i.e., less protophyllic) than HC1 and, therefore, many base-hydrochlorides (i.e., chlorides) may be titrated with standard HC104, just as carbonates may be titrated in aqueous solution with standard HC1. 

Conversion of a Mannich base hydrochloride into an a,/ -unsaturated carbonyl compound, is illustrated by the formation of phenyl vinyl ketone, which is obtained directly by steam distillation (Expt 6.147). Alternatively the Mannich base may be treated with methyl iodide to form the quaternary salt, which then gives the a,/ -unsaturated carbonyl compound by a base-catalysed elimination reaction. 

The forms of pentazocine recognized by the U.S.P. include pentazocine base, hydrochloride and lactate salts in the following formulations (1,3,4). 

Few studies have been made of the reactions of this class of complex. The action of bases upon the complexes brings about reductive elimination of hydrogen halide (equation 207).973 However, if this reaction is carried out in dichloromethane it appears that the hydrido ligand reduces the solvent since, although the base hydrochloride is formed, a rhodium(III) complex results (equation 208).953 The action of bromine989 or S02953 also produces hydrogen halide (equations 209 and 210). (The reaction with concentrated nitric acid has already been mentioned in Section 48.6.3.3,ii above.953)... 

Hydrogenation of dihydrostreptobiosamine hydrochloride and of streptobiosamine hydrochloride with platinum oxide catalyst resulted in the absorption of one and two moles of hydrogen, respectively. Acetylation of the products yielded in each case a crystalline compound which, however, was not the expected heptaacetyltetrahydrostreptobiosamine, but a base hydrochloride of the composition CjaHjoOgN(CH3C0)6-HC1-CjHsOH. The mole of ethanol, which could not be removed by drying... 

Deamination of Manriich bases hydrochlorides can also rurnish nUroulkenos 9 through pyrolysis (2( ) ... 

The structure of an alkaloid isolated from Streptomyces sp. NA-337 has been revised to (E,E)-2-pentadienyl-3,4,5,6-tetrahydropyridine (26). The absence of optical activity in the base hydrochloride precluded an earlier structure derived from a methylpyrrolidine and containing an asymmetric centre. 

Tosylation A solution of 5 mmol of Mannich-base-hydrochloride 1.1.6a in 10 mL of carefully dried pyridine was cooled to -10 °C and then mixed with 1.9 g (10 mmol) (rf tosylchloride. After stirring for 1 h at -10 °C and standing at room temp, for another 48 h the dark-colored reaction mixture was poured into crushed ice and acidified with dilute hydrochloric acid. The precipitated IV-tosylcompounds 1.1.6b were washed with dilute HCl and water and then recrystallized. 

The thermal decomposition of tetrahydroberberine methine base hydrochloride has been shown to yield an epimeric mixture of the rearranged product (216).215 An interesting transformation of a protoberberine into a benzophenanthridine alkaloid is discussed in Section 3J. Other work dealing with the synthesis of proto-berberine-type structures has been reported.216—218 A procedure for the preparation of radioiodinated (131I) berberine has appeared.219... 

A series of reactions, which ultimately led to a partially asymmetric molecule without intermediate resolution has been recorded. The penultimate step was the conversion of the amide-aldehyde (146) into the cyclohexenone derivative (147) by heating first with L-proline pyrrolidide and then adding methyl vinyl ketone. Ring closure to 148 was finally achieved by means of ethanolic hydrogen chloride. The resulting mesembrine (148) was partially optically active and the pure (-I- )-base hydrochloride was obtained from it by fractional crystallization 171). 

Difficulties in the synthesis of 4-chromanones by the condensation of 2-hydroxyacetophenone with formaldehyde and methylamine can be overcome through isolation of the Mannich base hydrochloride and its cydisation with potassium hydroxide (ref.78). 

For this synthesis (Scheme 24), deoxypiperoin (a) is condensed with the aminoacetaldehyde dialkyl acetal to the imine b and then, without isolation, it is reduced with sodium borohydride to the compound c. The yield was 60% from the ketone. Treatment of c with concentrated hydrochloric acid for five days at room temperature affords an isopavine base hydrochloride in 70% yield. Nine isopavine bases have been prepared in this manner. 

The base hydrochloride crystallizes from water giving yellow needles decomposing above 200°. The free base obtained from the hydrochloride as yellow needles melts 206-207° (decomp.). The base, which contains... 

Compound Base Hydrochloride Hydro- bromide Hydriodide ... 

Compound Formula Base Hydrochloride Methiodide Diacetate Other derivative ... 

Base Hydrochloride Hydro- bro- mide Hydriodide Perchlorate Picrate Chloro- aurate Other derivatives ... 

The tetracycline derivatives are amphoteric substances that can form salts with both acids and bases. Hydrochloride is the most common salt form and is used in a variety of dosage forms, including medicated feeds, soluble powders, tablets and boluses, intrauterine infusions, intramammary infusions, and injections. Because the tetracyclines are relatively inexpensive, they tend to be used as first-line antimicrobials, especially in ruminants and pigs. Uses include... 

Base hydrochloride, C16H27O2N2CI (mp 193°-196°) and seven other alkaloids recognized in chromatograms 115). 

Ondansetron has been described as the free base, hydrochloride salt and hydrochloride dihydrate and is available in a variety of formulations. These include hydrochloride tablets (4 and 8 mg) and solutions for injection (2 mg/ mL), oral lyophilisates (4 and 8 mg), sugar-free syrup (4 mg/5 mL as hydrochloride) and suppositories (16 mg). Alosetron hydrochloride tablets (0.5 and 1 mg) are most commonly obtainable. Tropisetron is also available as the hydrochloride salt and comes either as capsules (5 mg) or as a solution for injection at 1 mg/mL. Dolasetron mesilate products are formulated as film-coated tablets (50 and 200 mg) and 20 mg/mL solution for injection. Granisetron is also available as the hydrochloride salt and appears as film-coated tablets (1 and 2 mg) and 1 mg/mL solution for injection and dilution. 

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