Trans-Decahydro quinoline

Stereoisomers of the trans-decahydro-quinoline (228) (273) and the trans-decalin (229) (88) displayed extremely low orders of muscarinic effect, with the 2,3-ira/is-diaxial isomer of (229) being the most potent of the four stereoisomers of this structure (0.06%the potency of acetylcholine). 

Some heteropolycycloalkanes, e.g. indolizidine, quinolizidine, tropane, and decahydro-quinoline, are parent skeletons of alkaloids. Carbon-13 shifts of these and other parent polycycloalkanes [408] (Tables 4.64 and 4.65) are predominantly determined by heteroatom electronegativity, ring size, stereoisomerism, and dynamic effects. Aza- and thiade-calins are representative examples (Table 4.64). As described for cis- and trans-decalin (Section 4.1.3), carbon nuclei in the cis isomers of aza- and thiadecalins are shielded... 

Pumiliotoxin C alkaloids. Alkaloids of this general type are c/s-decahydro-quinolines substituted at C2 and C5. Overman and Jessup have devised a general synthesis for these alkaloids, shown in equation (1) for synthetic equivalent of trans- -amino-1,3-butadiene, with a j3-alkyl-substituted rrans-a, -unsaturated aldehyde. Thus the dienecarbamate 1 reacts with /ra s-crotonaldehyde at 100° (2.5 hours) to form a single adduct (2) in 617o yield (10-15% of 1 is recovered). Wittig-... 

In contrast, the 7,8-benzo-fused perhydropyridol[l,2-c]pyrimidine 2-methyl-2,3,4,4a,5,6-hexahydro-l//-pyrimido[3,4-a]quinoline exists in solution as 80% equatorial N-methyl trans conformer 365 in equilibrium with 20% of the axial N-methyl trans conformer 366.303 H-NMR studies303 on three diastereoisomeric 7-methyl-6,7,8,9,10,l 1,1 la,l 16,12,13-decahydro-7a W-quino [ 1,2-c] quinazolines 367-369 indicate the almost exclusive existence of 367 in the trans-fused conformation 370, of 368 as 56% 371 44% 372 and of 369 as 80% 373 20% 374. The conformational preferences... 

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