Although the mechanism of action of diphenidol on the vestibular system has not yet been elucidated, it exerts an anticholinergic effect due to interactions with mACh receptors, particularly M1, M2, M3 and M4. Hence, its actions may take place at the vestibular nuclei, where a significant excitatory input is mediated by ACh receptors, and also at the vestibular periphery where mACh receptors are expressed at efferent synapses. A series of selective mACh-receptor antagonists based on the diphenidol molecule has been synthesized, but they have not yet been the subject of clinical trials.[1]
Synthesis
Alkylation of 1-Bromo-3-chloropropane [109-70-6] (1) with piperidine (2) gives 3-Piperidinopropyl chloride [1458-63-5] (3). The Grignard reaction of this intermediate with benzophenone [119-61-9] gives the benzhydrol and hence, Diphenidol (4).
^Katz, Leon; Karger, Lawrence S. (1952). "The Mannich Reaction on α,α-Diphenylacetone". Journal of the American Chemical Society. 74 (16): 4085–4086. doi:10.1021/ja01136a034.
^Gautier, J.A. et al, Bull. Soc. Chim. Fr., 1964, 2145.
^Marxer, A. (1941). "Grignard-Reaktionen mit Halogen-alkyl-aminen". Helvetica Chimica Acta. 24 (2): 209E–225E. doi:10.1002/hlca.19410240225.
^Vitale, Arturo A.; Doctorovich, F.; Sbarbati Nudelman, N. (1987). "One-pot synthesis of diarylalkylcarbinols and substituted derivatives through carbon monoxide insertion reactions into aryllithiums". Journal of Organometallic Chemistry. 332 (1-2): 9–18. doi:10.1016/0022-328X(87)85117-3.
^Schmidt, Andreas; Marchetti, Mauro; Eilbracht, Peter (2004). "Regioselective hydroaminomethylation of 1,1-diaryl-allyl-alcohols: a new access to 4,4-diarylbutylamines". Tetrahedron. 60 (50): 11487–11492. doi:10.1016/j.tet.2004.09.058.
^Marxer Adrian, Miescher Karl, U.S. patent 2,411,664 (1946 to Ciba Pharmaccutical Products I).
^Barrett Paul Anthony & Wilkinson Samuel, GB683950 (1952 to Wellcome Found).