5- Laudanosine

Benzylisoquinoline Derivatives. Papaverine, C20H21O4N Xanthaline, C20H19O5N dZ-Laudanine, C20H25O4N Laudanidine, C20H25O4N Codamine, C20H25O4N Laudanosine, C21H27O4N... 

Special Reactions of Papaverine. Papaverine undergoes a number of reactions, which are of interest as providing methods of synthesis for other alkaloids, of which examples will be found under laudanosine, laudanine, laudanidine, codamine (pp. 187-195), berberine (p. 331), corydaline (p. 284), and glaucine (p. 311). 

Laudanosine, C21H27O4N. This alkaloid occurs in the liquor from which thebaine is precipitated, and can be isolated by Hesse s method. The crude alkaloid is purified by extraction with small quantities of ether, in which laudanosine is soluble, and finally by precipitation with potassium iodide. The free base crystallises from hot benzene in needles, m.p. 89°, [ ] f 103-23° (EtOH), is soluble in alcohol, chloroform, hot benzene or... 

Laudanosine contains four methoxyl groups. By exhaustive methyla-tion it yields trimethylamine and laudanosene (tetramethoxy-o-vinyl-stilbene), CH2=CH—C6H2(OCH3)2—CH=CH—C6H3(OCH3),. On oxidation with manganese dioxide and sulphuric acid it furnishes, in addition to the interesting by-product 2 3 6 7-tetramethoxy-9 10-dihydroanthracene, veratraldehyde and 4 5-dimethoxy-2 )3-methyl-... 

The constitution of laudanosine was determined by Pictet and Athanasescu/ who prepared it by reducing papaverine methochloride with tin and hydrochloric acid and deracemising the dZ-laudanosine (iV-methyltetrahydropapaverine) so obtained, by fractional crystallisation of the quinate. Laudanosine must, therefore, be represented by formula... 

A complete synthesis of laudanosine was effected by Pictet and Finkelstein by the condensation of omoveratrylamine (I) with homo-veratroyl chloride (II), giving omoveratroyl omoveratrylamine, which with phosphoric oxide undergoes cyclisation to 3 4-dihydropapaverine (III), which was converted into the methochloride and reduced to laudanosine (IV). 

Laudanosoline and Dehydrolaudanosaline. When laudanosine is de-methylated it yields laudanosoline, first prepared by Oberlin, ... 

Codamine contains one hydroxyl and three methoxyl groups. On methylation it furnishes d-laudanosine. The position of the free hydroxyl... 

This with potassium hydroxide in methanol forms de-OiV-dimethylarmepavine, m.p. 86-7°, (B. HCl, m.p. 229-30°) of which the methiodide, m.p. 233-4°, on treatment with alkali decomposes into trimetHylamine and a -p-anisyl-/3-(3 4-dimethoxy- 6 - vinylphenyl) -ethylene, m.p. 79°. The latter is oxidised by permanganate in acetone to anisic and m-hemipinic acids. With ethyl sulphate and alkali, armepavine gives 0-ethylarmepavine, an oil, which permanganate oxidises to p-ethoxybenzoic acid. Armepavine is similarly oxidised to p-hydroxybenzoic acid and l-keto-6 7-dimethoxy-2-methyl-1 2 3 4-tetiahydrowoquinoline and is therefore 6 7-dimethoxy-l-p-hydroxybenzyI-2-methyI-l 2 3 4-tetrahydrowoquinoline, i.e., it is laudanosine (p. 187) with MeO. at C replaced by H and MeO at C changed to HO. ... 

Reviews of recent work on spasmolytic drugs have been published by Raymond and by Blicke, and a detailed account of the action of papaverine and its derivatives, including laudanosine and laudanine with numerous references to literature is given by Krueger, Eddy and bumwalt. ... 

The first postulate may be illustrated by the still unrealised conversion of laudanosine into glaucine by oxidation, resulting in the loss of one atom of hydrogen from each aromatic nucleus and union of these as shown by the dotted line. 

Among examples of the use of this method of internuclear cycliza-tion in heterocyclic chemistry is the conversion of diazotized amino-laudanosine (14) to 2,3,5,6-tetramethoxyaporphine (15), Eq, (23). ... 

Durch intermolekulare Verkniipfung ist Laudanosin in bemerkenswert guter Ausbeute herstellbar3 ... 

Scheme 2 Structures of the benzylisoquinoline alkaloid laudanosine and its transformed products (2, 3, and 4) by utilizing Pseudomonas putida incubated at 30 °C for 96 h [47]... 

These transformation reactions are similar in part to those previously observed for laudanosine (201) and for the aporphine-benzylisoquinoline alkaloid thalicarpine (202). Laudanosine underwent regiospecific O-demethylation at... 

Laudanosine, 2 87, 89 Laue method, for macromolecule X-ray diffraction, 26 442 Laundering... 

Die Konfiguration des natiirlichen (+)-Laudanosins, sowie verwandter Tetrahy-dro-isochinolin-, Aporphin- und Tetrahydro-berberin-alkaloide, by H. Corrodi and E. Hardegger, Helv. Chim. Acta, 39 (1956) 889-897. 

These substrates possess several oxidiz-able sites. Racemic laudanosine (71), for example, could be oxidized at nitrogen or in one or both of the electron-rich aromatic rings. In fact, it displays ve volta-metric peak potentials at 0.63, 0.81, 1.13, 1.30,andl.47 V(vsAg/AgN03). Yet,using potential control, it proved a simple matter to oxidize a dimethoxyaryl unit in the presence of the Ai-methylamine subunit. 

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