Tropidine

The results so far recorded are those upon which Ladenburg chiefly based his formulae representing tropine and tropidine as A-methyl-J -tetrahydropyridines, substituted in position 2 by the residues. CHa. CH OH (or. CHOH. CH3) for tropine (XIV) and, CH CH for tropidine (XV) thus ... 

The inadequacy of these formulae became evident when the oxidation of tropine was studied. With potassium permanganate, in presence of acid, or with chromic acid, tropine and tropidine give rise to a series of oxidation products, the interrelationships of which are shown in the scheme on p. 75. 

XXV) for tropidine and since tropilene, C,HioO, gives a monobenzylidene derivative and must contain a —CO—CHj— group it is represented by... 

Willstattcr s formula for tropine was confirmed by his syntheses of tropidine, tropine and 0-tropinc from the heptacyclic ketone, suberone as a starting-point. The latter was converted into the oxime, whieh was... 

The conversion of a-methyltropidine into tropidine methiodide was subsequently achieved in another way. By saturating a solution of the base in hydrochloric acid with hydrogen chloride, the elements of the latter were added on in the J -position and the product on treatment with sodium carbonate solution yielded methyl- -tropine. The latter was next brominated in positions 4 and 5, The dibromide, thus formed,... 

This synthetic tropidine was converted into bromodihydrotropidine by hydrogen bromide in aeetie aeid, and the solution heated with 10 per cent, sulphurie acid at 200-10°, when it passed into -tropine,and, sinee this may be partially converted into tropine by oxidation to tropinone and reduction of the latter by zinc dust and hydriodic acid, this series of reactions affords a complete synthesis of tropine and of the tropeines. Combining the formula given above for tropine with that of tropic acid, atropine and hyoscyamine are represented as follows ... 

Tropidine CgHj3N —Tropilidene C,Hg (S-cyclo Heptatriene) Anhydroecgonine C9H13O2N —> -eycloHeptatrienccaTboxylic acid CjHgOj... 

WiUstatter, R. (1901) Synthese des Tropidins. Berichte der Deutschen Chemischen Gesellschaft, 34, 129-144. 

Routes C, D, and E. In these routes the C-3 ester function is cleaved under forms of RCOO% RCO-, and RCOOH, respectively. In the last case, ionized tropidine is formed. Concomitant losses of ethylene and hydrogen radical lead again to the /V-methylpyridinium ion (cf. Route A). 

Although /V-methyltetrahydropyridines are not selectively hydroformylated, an equal mixture of the two aldehydes being obtained from /V-methy 1-1,2,3,6-tetrahydropyridine, W-methyltropidenes are selectively formylated at the 3-position (equation 29). The difference in the selectivity can be attributed to the substitution in tropidine (bridge head carbon). 

Transmetallation between CpZrCl3 and the rrob-stannylated tropidine, with concomitant elimination of Me3SnCl, yields mono-Cp zirconium dichloride 3 77282 (Scheme 83), bearing the 774-tropidinyl ligand which functions as a... 

When hydrochloric acid or hydrobromic acid is the hydrolytic agent the replacement of the alcoholic hydroxyl of tropine respectively by chlorine or bromine has been observed to occur (186), while sulfuric acid causes dehydration to the unsaturated base, tropidine (192a). 

A second exhaustive methylation and Hofmann degradation eliminates the nitrogen of a-methyltropidine as trimethylamine. These last two reactions demonstrate that the tertiary nitrogen of tropidine (and hence of tropine)... 

Hydriodic acid and phosphorus (22), like hydrochloric or hydrobromic acid replaces the hydroxyl of tropine by a halogen atom. The reductive elimination of this iodine atom from iodotropane by nascent hydrogen (Zn + HCl) provided the first preparation of the parent substance, tropane (dihydrotropidine) (I, R = CH3). (A more direct preparation of tropane is by the catalytic reduction of tropidine over platinum black (159a)). Tropane reacts readily with hydrogen chloride at an elevated temperature eliminating methyl chloride with the formation of a new saturated base, nortropane (94). The methyl group eliminated from tropane must have been attached to the nitrogen, for nortropane, in contrast to tropane, forms a well defined A-nitroso derivative. The isolation of methyl chloride and the secondary amine, nortropane, confirms the earlier assumption of the... 

Structure XII was favored by Merling, for like Fischer s triacetonealka-mine, XIV (the mandelic ester possesses mydriatic properties (86)), the hydroxyl is gamma with respect to the nitrogen. Tropidine would then have an unsaturated iSmns-bridge while tropinic acid would be iV-methyl-... 

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