Antihistamine reagent

When the additional nitrogen atom is included in one of the aromatic rings, on the other hand, there is obtained a compound with antihistaminic properties. Reaction of the Grignard reagent from 4-chlorobromobenzene with pyridine-2-aldehyde gives the benzhydrol analog (12). The alcohol is then converted to its sodium salt by means of sodium, and this salt is alkylated with W-C2-chloroethyl)dimethylamine. Carbinoxamine (13) is thus obtained. ... 

The presence of unsaturation in the side chain is also compatible with antihistaminic activity. Mannich condensation of p-chloroacetophenone with formaldehyde and pyrollidine affords the amino ketone, 109. Reaction with an organometallic reagent from 2-bromopyridine gives 110. Dehydration leads to triproli-dine (111). ... 

Reaction of the Mannich product (112) from acetophenone itself with the Grignard reagent from p-chlorobcnzyl chloride gives the carbinol, 113. Dehydration in this case gives the antihistamine pyrrobutamine (114). It is not immediately clear why dehydration does not occur in the other sense so as to afford the energetically more favored stilbene. 

To anticipate briefly, shortening the length of the side chain in the phenothiazines from three to two carbon atoms changes I he activity of the products from neuroleptics to antihistaminic iigents. A rather similar effect is seen in the tricyclic antidepressants. Reaction of ketone, 27, with the Grignard reagent I rom 4-chloro-l-methylpipyridine (35) affords the tertiary alco-liol, 36. Dehydration gives the antihistamine, cyproheptadine (37). ... 

Chiral /3,/3-diaryIpropionic acid moieties are often found in compounds showing biological activities, such as antiarrhythmics vasodilators antidepressives " , antihistamines and controllers of cerebral insufficiency ". In the course of synthetic studies of chiral -diaryIpropionic acid derivatives, Merck researchers developed stereoselective conjugate addition of aryllithium reagents to the a,/ -unsaturated fert-butyl esters 18 bearing a chiral imidazolidine or oxazolidine auxiliary at the ortho position of an aryl group. The addition furnished chiral -diaryIpropionic acid derivatives 19 with... 

Cyclodehydration. The commercial preparation of an antihistamine (Lorata-dine, 3) requires cyclodehydration of the ketone 1. Use of the usual reagent for this reaction, polyphosphoric acid at 190°, leads to a mixture of two products in about 45% yield. The most useful and reasonably priced reagent is HF and BF3 at -30°, which gives 2 in >90% yield. 

Antihistaminics, being tertiary amines, are analysed after reaction with an analogous reagent [566] with pentafluorobenzyl chloroformate a derivative is formed with a high ECD response and good GC properties, e.g., on OV-17. Hucker and Miller [567] subjected amitriptyline and other tertiary amines to exhaustive methylation and analysed the products from the reaction (Hoffman). Whereas the initial substances gave considerable tailing on 3% of QF-1, the derivatives provided sharp and symmetric peaks. 

Marquis Test (p. 139). Many basic drugs produce colours with diis reagent. It is a good test for opiates, stimulants, antihistamines, and pheno-thiazines. 

Use Manufacture of antihistamines, resin and rubber stabilizer, reagent for aldehydes. 

Other literature presented a rapid method for the determination of Dioxopro-methazine hydrochloride (DPZ) (an antihistamine drug) by CE-ECL using Ru(bpy)3 reagent. The proposed method was of high sensitivity, good selectivity, and reproducibility for DPZ analysis. This CE-ECL method was applied to analyze DPZ in real samples including tablets, rat serum, and human urine [45]. 

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