Orchidaceae alkaloid

There are only two groups of alkaloids that appear to be derived from tyrosine (25, R = OH) utilized as a Cg—C2 fragment and a Cg—Cj unit which comes from phenylalanine (25, R = H). The first is that small group found only in the Orchidaceae, exemplified by cryptostyline I [22324-79-4] (67, from Cryptostylisfulva Schltri) C29H22NO4. 

The trimer famesyl pyrophosphate (35), in addition to serving as a pregenitor of steroids via squalene (114), is also the pregenitor of the compounds known as sesquiterpenes. It has been suggested that famesyl pyrophosphate (88) similarly serves as the carbon backbone of alkaloids such as deoxynuphatidine (120) ftom Nupharjapomcum (Nymphaceae) (water hhes) and dendrobine (121) Dendrobium nobikl indl. (Orchidaceae) (Table 11). 

Luning, B. 1964. Studies of species Orchidaceae alkaloids. I. Screening of species for alkaloids. Acta Chem. Scand. 18 1507-1516. 

Although the indolizine nucleus appears not to occur naturally, its perhydro derivative, commonly named indolizidine, is the alkaloid 8-coniceine, and this nucleus is to be found in several groups of alkaloids including those from the plant groups Ipomoea, Elaeocarpus, Tylophora, Amaryllidaceae, and Orchidaceae. Since the chemistry of these alkaloids has been reviewed regularly,1 only selected examples will be taken from the natural products field. 

Okamoto T, Natsume M, Onaka T, Uchimaro F, Shimizu M (1972) Further Studies on the Alkaloidal Constituents of Dendrobium nobile (Orchidaceae)-Stmcture Determination of 4-Hydroxydendroxine and Nobilomethylene. Chem Pharm Bull 20 418... 

Hedman K, Leander K, Liining B (1971) Studies on Orchidaceae Alkaloids XXV. N-Isopentenyl Derivatives of Dendroxin and 6-Hydroxydendroxine from Dendrobium frie-dericksianum Lindl and Dendrobium hildebrandii Rolfe. Acta Chem Scand 25 1142... 

Hedman K, Leander K (1972) Studies on Orchidaceae Alkaloids XXVII. Quaternary Salts of the Dendrobine Type from Dendrobium nobile Lindl. Acta Chem Scand 26 3177... 

Granelli I. Leander K, Liining B (1970) Studies on Orchidaceae Alkaloids XVI. A New Alkaloid, 2-Hydroxy dendrobine, from Dendrobium findlayanum Par. et Rchb. f Acta Chem Scand 24 1209... 

Blomqvist L, Brandange S, Gawell L, Leander K, Liining B (1973) Studies on Orchidaceae Alkaloids XXXVII. Dendrowardine, a Quaternary Alkaloid from Dendrobium wardianum. Acta Chem Scand 27 1439... 

Lee CH, Westling M, Livinghouse T, Williams AC (1992) Acybiitrilium Ion Initiated Heteroannulations in Alkaloid Synthesis. An Efficient, Stereocontrolled, Total Synthesis of Orchidaceae Alkaloid ( )-Dendrobine. J Am Chem Soc 114 4089... 

Nupharolidine (25), a new sesquiterpene alkaloid, has been isolated from Nuphar luteum and characterised mainly by spectral means. The Dendrobium species (Orchidaceae) is known to be rich in sesquiterpene alkaloids. A taxonomic survey of Australian Orchidaceae which includes a discussion of Dendrobium has appeared. ... 

Several useful reviews and compilations of data on pyrrolizidine alkaloids have been published. These include a review of all aspects of pyrrolizidine alkaloid chemistry and biochemistry this is comprehensive, but rather idiosyncratic in its balance (sixteen pages are devoted to the synthesis of necines and necic acids whereas physical and spectroscopic properties of the alkaloids are discussed in barely two.) Nevertheless, this up-to-date work will certainly be of great interest and usefulness to workers in the field. Klasek has surveyed the investigations on pyrrolizidine alkaloids carried out at Olomouc, and Atal and Sawhney have produced a useful compilation of data on alkaloids from Indian Crotalaria species. Pyrrolizidine alkaloids from the Orchidaceae have been surveyed by Luning" and by Brandange. Pyrrolizidine alkaloids are included in a comprehensive compilation of data on alkaloids isolated from plants occurring in the U.S.S.R. ... 

Dendrobium pierardii Roxb. (D. aphyllum Roxb.) (Orchidaceae) (Vol. 1, p. 459) Pierardine (71) has now been synthesized and shown to possess the (S) configuration. Condensation of the lithium salt of phthalaldehydic acid with 3-dimethylaminopropylmagnesium chloride followed by lactonization with acid gave ( )-pierardine, which was resolved by recrystallization of its di-0-benzoyl-L-tartrate. The (— )-enantiomer was shown to be identical with an authentic sample of the alkaloid. The absolute configuration of pierardine as (3S)-(3-dimethylaminopropyl)phthalide (71) was determined by comparison of... 

CgHjjNO, Mr 141.21, liquid, bp. 77 °C (1.5 kPa), R-fonii [a]Q +45° (CgHjOH), 5-form [a] -57.2° (CjHsOH). H. is a readily racemizing alkaloid from some Dendrobium species (Orchidaceae), bindweeds (Convolvulaceae), coca leaves, and roots of many plants containing tropane alkaloids. 

Phenyltetrahydroisoquinoline alkaloids. Rare structures that only occur in orchids (Orchidaceae), e. g., cryptostyline I C 9H2,n04, Mr 327.4, mp. 101-102°C, [aJo +56° (CHCI3) from Cryptostylis... 

Orchidaceae (nine genera). Additional pyrrolizidine alkaloid-producing plants are scattered throughout six other unrelated families 164). 

The alkaloid anosmine (l,2,3,4,6,7,8,9-octahydrodipyrido[l,2-a l, 2 -c]imidazol-10-ium bromide) was isolated from Dendrobium anosmum Lindl. and from Dendrobium parishii Rchb. f. (Orchidaceae) [331]. Its structure was confirmed by synthesis and by X-ray crystallography [332]. 

A series of alkaloids belonging to this group of sesquiter-penoid compounds occurs in the genus Denbrobium of the Orchidaceae (Cane, 1981 Coscia, 1969). Denbrobine (87) is one of the most common of these alkaloids. 

Alkaloids are found most commonly in dicotyledonous angiosperms and are uncommon in algae, bryophytes, ferns, and monocotyledonous angiosperms. However, alkaloids are known from the lower plant Lycopodium, and from the monocotyledonous families Amaryllidaceae, Dioscoreaceae, Liliaceae, Orchidaceae, and Poaceae. Alkaloids are not common in gymnosperms, although they are encountered in several conifers and occasionally in other gymnospermous groups. 

Tropane alkaloids are common in the Solanaceae, but are found in several other plant families. Tropane alkaloids are found in the tribes Cestreae, Datureae, Nicandreae, Salpig-lossideae, and Solaneae (Evans, 1979). These alkaloids also are found in the Convolvulaceae, which most systematists consider to be related closely to the Solanaceae (Waterman and Gray, 1987). Other families that contain tropane alkaloids are the Brassicaceae Cochlearia), Dioscoreaceae, Elaeocarpaceae, Erythroxylaceae, Euphorbiaceae Phyllan-thus), Orchidaceae, Proteaceae, and Rhizophoraceae (Dahl-gren et al, 1981 Romeike, 1978 Waterman and Gray, 1987 Wooley, 1993). Because other types of alkaloids are found in several of these families, many reports should be confirmed (Romeike, 1978). 

Several indolizidine alkaloids are known from Dendrob-ium (Orchidaceae). Dendroprimine (34) is representative of these compounds (Howard and Micheal, 1986). 

A small group of isoquinoline alkaloids, in which substituted benzaldehyde derivatives such as 9 appear to be involved in the biosynthetic process, occurs in the genus Cryp-tostylis (Orchidaceae) (Fig. 32.4). Dopamine serves as a precursor for both aromatic rings of the system (Lundstrom, 1983). 

Several classes of sesquiterpene alkaloids have been reported these do not appear to be closely related biosyntheti-cally. Important among these alkaloids are those of Nuphar and Dendrobium (Orchidaceae), and the Celastraceae and Hippocrateaceae. About 130 sesquiterpene alkaloids are known (Verpoorte et al., 1991). 

---