Alkaloids of ergot

Isolation of Ergot Alkaloids. In the papers already quoted (refs. 6 to 19) the processes used for the isolation of the total alkaloids and the separation of the component bases are given to those may be added references to methods by other authors. There are also numerous patented processes, some of which are quoted in the following special sections. 

Stoll, Hofmann and Petrzilka (1946) have also succeeded in obtaining dihydro-derivatives of this series (ergotinine type) of ergot alkaloids. Each of these bases yields two dihydro-derivatives, distinguished as isomerides I and II. Their chief characteristics are siunmarised in the following table —... 

The Madelung indole synthesis has been employed in the preparation of some complex indole systems. Uhle et al. reported the conversion of N-formyl-5,6,7,8-tetrahydronaphthylamine 28 into 1,3,4,5-tetrahydrobenz[c,ti]indole 29 with t-BuOK in 11% yield in regard to synthesis of ergot alkaloids. ... 

Thus, our tungstate method is proved to be applicable even to ergot alkaloids. Synthesis of 316 and various 1-hydroxy derivatives of ergot alkaloids could be carried out in the near future. 

DinitrQ-ll-Qxatricyclo[6 2 1 0 undec-9-ene has been prepared by an intramolecular Diels-Alder reacdon of the furan with a idtroalkene group as shown in Eq 8 26 This tricyclic compound is a versatile synthedc tool for the preparadon of ergot alkaloids... 

Today, 2-bromo-a-ergocryptine (bromocriptine) is the second (after dihydroergotoxine) most extensively used compound from the group of ergot alkaloids. 

Table 2. Physico-chemical properties of 2-(2, 3 -dihydro-3 -oxo-r,2 -benzisothiazolyl-r,r dioxide) derivatives of ergot alkaloids U... 

The designation Van Urk s reagent can be traced back to a publication in 1929 [7] which describes the detection of ergot alkaloids with 4-(dimethylamino)-benzadehyde in aqueous solution by cautiously underlayering with concentrated sulfuric acid. 

The natural fluorescence of ergot alkaloids is considerably augmented by the reagent [1]. Heating for longer than 3 min or to more than 80 °C leads to a reduction in fluorescence intensity and, hence, should be avoided [3]. 

In the face of the failure of rational approaches in the treatment of AzD it is perhaps not surprising that there have been many less rational ones. These include the use of vasodilators and nootropics. The former, such as hydergine, a mixture of ergot alkaloids, are intended to increase cerebral blood flow and neuronal metabolism despite some reduction in blood pressure, while the latter, like piracetam, are metabolic stimulants that increase cerebral metabolism and ATP production. Neither are of proven value in AzD. 

Rebek, J., Jr., Tai, D.R, Shue, Y.K. (1984) Synthesis of Ergot Alkaloids from Tryptophan. Journal of the American Chemical Society, 106, 1813-1819. 

Scholten, A. H. M. T. and Frei, R. W., Identification of ergot alkaloids with a photochemical reaction detector in liquid chromatography, /. Chromatogr., 176, 349, 1979. 

Hindmarch I, Parrott AC and Lanza M (1979). The effects of ergot alkaloid derivative (Hydergine) on aspects of psychomotor performance, arousal, and cognitive processing ability. Journal of Clinical Pharmacology, 19, 726-732. 

For chromatographic purification of ergot alkaloids from seed extracts see Phytochem. 11,1479(1972). 

An entirely different approach to 3-haloindoles involves a mercuration/iodination sequence, which has been adopted by Hegedus to prepare 4-bromo-3-iodo-l-(4-toluenesulfonyl)indole for use in the synthesis of ergot alkaloids [20,21], We will discuss this chemistry later. 

In his general studies aimed at the synthesis of ergot alkaloids, Hegedus effected the coupling of dihaloindole 79 with the zinc reagent 80, generated in situ from l-methoxy-l,2-propadiene, to afford ketene 81 [21],... 

Yang described the Pd-induced cyclization of an aryl bromide onto a pendant cyano group leading to y-carbolines and related compounds [488], Genet studied the use of chiral palladium complexes in the construction of the C-ring of ergot alkaloids, a study that culminated in a synthesis of (-)-chanoclavine I [489-491]. For example, nitroindole 388 is cyclized to 389 in 57% yield and with enantioselectivities of up to 95% using Pd(OAc)2 and (S)-(-)-BINAP. 

On the Biogenetic Interrelations of Ergot Alkaloids. 3. Internationales Sjrmposium, .Biochemie und Physiologic der AUcaloidc", Halle (Saale) 24.-27. Juni 1965. 

Biogenetic Interrelationships of Ergot Alkaloids. Arch. Biochem. 

Bhattacharji, S., A. J. Birch, A. Brack, A. Hofmann, H. Kobel, D. C. C. Smith, H. Smith and J. Winter Studies in Relation to Biosynthesis. Part XXVII. The Biosynthesis of Ergot Alkaloids. J. cheni. Soc. [London] 1962, 421. 

Weygand, F, and H. G. Floss The Biogenesis of Ergot Alkaloids. Angew. Chem. intemat. Edit. 2, 243 (1963). 

The Structure of Ergot Alkaloid, Elymoclavine. Bull, agric. chem. Soc. Japan 19, 94 (1955). 

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