Type Alkaloids

Mass spectra of compounds 11 are characterized by the presence of fission products of the molecule tricyclic moiety (m/e of fragments depending on alkaloid type) and ergolene moiety with m/e 448 and after SO2 elimination m/e 384 = 448 -SO2. The characteristic IH-NMR is the absence of signal for C - 2 proton and a new multiplet at region 7-7.5 ppm for aromatic protons from saccharin moiety. 

Spar = Sparteine type Lupa = Lupanine type Lows = Low alkaloid content Others = Other alkaloid types. 

Another interesting observation using molecular sieves supported by Ru catalysts is the one related to the effect of the modifier. The use of an alkaloid-type modifier, like cinchonidine, enhances the d.e. to the same (1 IS, 15R) form. But the use of TA leads to a decrease in the d.e., and the addition of pivalic acid in mixture with TA leads to a spectacular inversion in diasteieoselectivity, resulting in the isomer with natural-like configuration, namely (1 IS, 15S). 

Scheme 87 Alkaloid-type compounds by reductive alkylation of iminium salts.

The electroreduction of iminium salts in the presence of alkyl halides has been applied to the synthesis of alkaloid-type compounds as depicted in Scheme 87 [127,128]. 

Moreover, polycyclic indole alkaloid-type molecules 225 with a ketopiperazine were prepared by Wang et al. using Ugi-Pictet-Spengler process [68]. Ketocar-boxylic acids 227 were used as bifunctional substrates in Ugi reaction to yield lactams of varying ring sizes (Scheme 41). A diastereomer of hexacyclic indole derivative was crystallized and yielded X-ray diffraction suitable crystal to assign the stereochemistry. 

Scheme 41 Synthesis of polycyclic indole alkaloid-type compounds 225. The X-ray structure of compound 225D is shown in blue sticks (CCDC-749252)...

Alkaloid Type Precursor Chemical Group of Parent Examples of... 

Group of Amino Acids/Amino acids Alkaloid Type Participation in Alkaloid Synthesis... 

Methylation at C-4 of sterol nucleus was one of the other factors affecting activity enhancement. Thus, in general, 4-methylsterols (14,15) and 4,4-dimethylsterols (8,13) exhibited higher activity than 4-desmethylsterols. A similar structure-activity relationship was observed also in the HHPA-induced inflammation on mouse ear [35]. Whereas cholesterol (7) did not show inhibitory activity, several 4,4-dimethylcholestane derivatives, 0-12, exhibited activity. 4,4-Dimethylcholestane-3a,5a-diol (12) was the most potent inhibitor its activity was comparable to that of ursolic acid (210) [35]. Compound 12 reduced also the inflammation induced by teleocidin B (3), one of the indole alkaloid-type of tumor promoters [53]. 

Among the many chemical alkaloid types found in the family are alkaloids of tropanc, steroid, -carboline, nicotine, hygrine, and other structures responsible for many of the uses of the medicinal and hallucinogenic species of the group. 

Hillman reactions leading to products with 99% ee have been reported by the Hata-keyama group [27]. The reaction was performed with 10 mol% of an alkaloid-type organocatalyst. 

Despite the great achievements made over the years in alkaloid-type asymmetric alkylation of glycinates, however, to the best of our knowledge commercial application of this method on an industrial scale for production of optically active a-amino acids has not yet been reported. Nevertheless, because of the high efficiency achieved by use of the state of the art of this methodology, the prerequisite for applications on industrial scale have now been realized, and commercial applications can be expected in the future. 

Synthesis of the anti-arrhythmic drug ajmaline from Rauvolfia plants, an efficient source of several alkaloid types used in therapy, represents an even more advanced study of the total enzymatic synthesis of terpenoid indole alkaloids. Ajmaline is a class I anti-arrhythmic alkaloid because of its activity as heart muscle sodium channels antagonist [35],... 

The 1.2.3.4-tetrahydroisoquinoline skeleton represents the framework found in many isoquinoline alkaloid derivatives and not only from plants. Some derivatives attracted much interest because of their anti-cancer activity [124], which has prompted many groups to invest in their chemical synthesis. The Pictet-Spengler reaction has become an important method in the preparation of this alkaloid type, and has often been described with phenylalanine derivatives and pyruvates as starting materials. Synthesis of appropriate tetrahydroisoquinoline-3 and the corresponding tetrahydroisoquinoline-1-carboxylic acid has been the key target [125]. 

As described above, the carbon-carbon bond formation at the a-position of amines using anodically a-methoxylated carbamates as the starting compounds is highly useful for the synthesis of alkaloid type compounds, however, this method is limited only to the bond formation at the a-position. On the other hand, it has been found that the elimination of methanol from the a-methoxylated carbamates 47 yields the corresponding enecarbamates 48 in high yields 30). 

The first isolation of the Lythraceae alkaloids from Decodon verticillatus (L) Ell was reported by Ferris in 1962 (2). Those were lactonic biphenyl alkaloids (type A) decinine, decodine, verticillatine, decamine, vertine, lactonic ether alcaloids, decaline, and vertaline. 

In 1967, Fujita et al. (5,6) isolated three piperidine metacyclophane alkaloids (type B) from Lythrum anceps Makino. The third structural variant of the Lythraceae alkaloids, quinolizidine metacyclophane (type C), was... 

On the other hand, a significant homogeneous catalysis was ruled out by specific requirements for the immobilized alkaloid type B, which can deliver uniformly high activity and enantioselectivity levels after recycling, thanks to substantial chemical stability and effective swelling due to the hydrophilic diethylene glycol side-chains[140] (Scheme 9.4). 

Alkaloid type and name ture formula (MW) Species Reference(s) ... 

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