Hydrobromide salt

Scopolamine (42), an optically active, viscous Hquid, also isolated from Solanaceae, eg. Datura metell. decomposes on standing and is thus usually both used and stored as its hydrobromide salt. The salt is employed as a sedative or, less commonly, as a prophylactic for motion sickness. It also has some history of use ia conjunction with narcotics as it appears to enhance their analgesic effects. BiogeneticaHy, scopolamine is clearly an oxidation product of atropiae, or, more precisely, because it is optically active, of (—)-hyoscyamiae. 

As described in U.S. Patent 2,667,351, o-methylbenzhydryl bromide is added slowly to (3-dimethylaminoethanol at refluxing temperature. After the addition has been completed the mixture is refluxed and stirred for an additional 16 hours. The mixture is cooled and the bottom layer consisting of the crude hydrobromide salt of (3-dimethylaminoethanol is drawn off. The excess amino alcohol is distilled from the upper layer in vacuo and the residue is reacted with citric acid. 

The dinitrile 1 (1.5-5.5 g) was dissolved in a mixture of CH2Cl2 (20 mL) and Et20 (200 mL). The solution was cooled in an ice bath to 0 C and a stream of anhyd HBr was bubbled through the solution for about 1.5 h. The solvent was removed under reduced pressure (water pump) to give a crystalline or syrupy residue of the azcpinc hydrobromide 2, which was crystallized (MeOH/acetone/Et20 or MeOH). The free bases 3 were liberated by pouring a solution of the hydrobromide salt in MeOH (10-20 mL) into an excess of aq NaHCOj. The mixture was stirred for 15-30 min, and the free base liberated was removed by filtration, then dried and crystallized (CH2Cl2). 

The alicyclic analogs 4 with hydrogen bromide in diethyl ether at room temperature behave similarly to yield the 4,5-fused 7-bromo-3/7-azepin-2-amines 5 as their hydrobromide salts. Yields are high except for the cyclooctane derivative (n = 4). Once again, the free bases are liberated by treatment with sodium hydrogen carbonate. 

Method B (More suitable for large-scale preparations).41 A solution of benzene-1,2-diacetonitrile (19 18 g, 0.115 mol) in HOAc (30 mL) was added dropwise to a stirred 30 % solution (72 g) of HBr in HOAc. After 2 h the benzazepinium hydrobromide was collected by filtration and the residue washed successively with HOAc and Et20, and then dried. A solution of the hydrobromide salt (28 g) in DMF (100 mL) was added dropwise with stirring to sat. aq NaHC03 (500 mL), and the resulting mixture filtered. The residue was washed with H20, and then dried to give the crude product which was crystallized (EtOAc) yield 16g (61 %) mp -lOS C. 

The readily accessible oxalamidine derivative PhN = C(NHBu )C(NHBu ) = NPh provides another useful entry into the coordination chemistry of oxalamidinato ligands. Scheme 195 summarizes the results of an initial study. Mono- and dinuclear complexes of Ti, Zr, and Ta have been isolated and fully characterized. Silylation of both N-H functions was achieved by subsequent treatment with 2 equivalents of n-butyllithium and MesSiCl. The preparation of a nickel(II) complex failed and gave a hydrobromide salt instead. ... 

Cyclization of a-cyanoalkyl cyanamides (74) with hydrogen bromide gave 4-aminoimidazoles (77) as their hydrobromide salts. These compounds (77) were found to be unstable as the free base but gave stable (V-acetyl derivatives (84 R2 = Br, R3 = COCH3) (33-82%) when treated with acetic anhydride in pyridine (64JOC153 66CA12211). 

CAS 108-18-9 819-79-4 (Hydrochloride Salt) 30321-74-5 (Hydrobromide Salt) 6143-52-8 (Nitrate Salt) 65087-26-5 (Sulfate Salt)... 

CAS 4368-28-9 39920-04-2 (Racemic mixture) 629653-73-2 (Acetate salt) 18660-81-6 (Citrate salt) 17522-62-2 (Formate salt) 4664-41-9 (Hydrobromide salt) 4664-40-8 (Picrate salt) 129497-92-3 (Trifluoroacetate salt)... 

MCjSO solution Hibbert (1974) Protonated amine salt with magnesium tristhexafluoro-acetylacetonate) (Truter and Vickery, 1972) CFjCOOH solution (Alder el al., 1968) Altman el al. (1978) Protonated amine salt with copper(ll) tris(hexafluoroacetylacetonate) (Truter and Vickery, 1972) Hydrobromide salt (Pyzalka el al., 1983) Staab el al. (1983) Staab el al. (1988a) Saupe ei al. (1986) Staab and Saupe (1988) Staab el al. (1988b) "Zirnstein and Staab (1987). 

Heating of the unprotected dipeptide or its hydrobromide salt in phenol. ... 

Its hydrobromide salt Is also crystalline with a melting point of 214-218°C. The hydrochloride is soluble In water, methanol, ethanol, aniline, and methylene chloride, and the base is almost insoluble in water and soluble in toluene, methanol, ethyl acetate, kerosene, and methylene chloride. The base (SNB) is crystalline with a melting point of 46-46.5°C. 

Free dipeptides or their hydrobromide salts can be cyclized to the corresponding cyclodipeptides by heating in phenol (68JOC862). No detectable racemization takes place. The versatility of the method is shown by the synthesis of cyclo(Ser-Tyr), cyclo(Met-Tyr), cyclo(Gly-Trp), etc. Very facile cyclization (on warming in water) of sarcosyldehydrophenyl-alanine to l-methyl-3-fra/is-benzylidenepiperazine-2,5-dione (14) has been reported [70JCS(C)2530]. 

Diamino-, straw colored ndls (from w), mp 128-29° readily sol in ale forms a hydrobromide salt (Ref 1) ... 

C-Alkylation of 1-methyl-1,2,3,4-tetrahydro-6//-pyrimido[l,2-b]isoquino-lin-6-one with benzyl bromide in boiling methylene chloride overnight in the presence of potassium carbonate, and with excess methyl iodide gave 11-substituted derivatives (113 and 114) (88HCA77). The treatment of hydrobromide salt of 11-benzyl derivative 113 with a base yielded 11-benzyl-1 -methyl-1,2,3,4-tetrahydro-6//-pyrimido[l, 2-6]isoquinolin-6-one (115). 

Benzyl (S)-2-[(,V)-5-Pyrrolidin-2-yl-1/7-tetrazol-1-yl]propanoate Hydrobromide Salt (66-HBr) 1"91... 

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