New synthesis and absolute configuration of tetrahydroisoquinoline cactus alkaloids

Brossi, Arnold; Blount, John F.; O'Brien, Jay; Teitel, S.

doi:10.1021/ja00752a041

Cited by 25 publications

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“…In 1960 Battersby and Edwards applied the somewhat uncertain comparison of the solvent-related changes in optical rotation with those of related compounds of known configuration to propose that the natural (-)anhalonine and (-)-lophophorine are both S isomers [21]. This was fortunately confirmed a few years later by X-ray crystallography and comparison of ORD and CD spectra and, contrary to expectation, the same configuration was similarly demonstrated for 1S-(+)-O-methylanhalonidine [22]. Finally, these results were used to develop a general rule that could be applied to determine the absolute configurations of 1-methyl-1,2,3,4-tetrahydroisoquinolines independently of the substitution pattern on the aromatic ring.…”

Section: The History Of Cactaceous Alkaloid Chemistry Begins With Louismentioning

confidence: 96%

Alkaloids of the Cactaceae — The Classics

Cassels

2019

Natural Product Communications

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Alkaloids of the Cactaceae have been studied for the last 120 years. The first half of that period provided the "classic" compounds, after which a large number of usually very similar analogs were isolated or determined with modern methods. Although some unusual synthetic approaches have been developed, their preparation is generally quite straightforward. Their biosynthesis has been studied but, particularly in the case of the isoquinoline compounds, important aspects have not been addressed. Due to its striking effects, the pharmacology of mescaline has been studied more intensely than that of the other phenethylamines present in cacti, followed only by hordenine. The many 1,2,3,4-tetrahydroisoquinoline alkaloids have attracted much less interest and have often been considered practically inactive. Nevertheless, some recorded activities of this group of compounds suggests a need for additional studies, especially in connection with their co-administration with mescaline, as in dried cacti and in beverages prepared from them.

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Section: The History Of Cactaceous Alkaloid Chemistry Begins With Louismentioning

confidence: 96%

Alkaloids of the Cactaceae — The Classics

Cassels

2019

Natural Product Communications

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“…However, the exact enzyme has yet to be demonstrated in the Cactaceae family. In 1971, the absolute configurations of (−)- 5 and (−)- 4 were determined by Brossi et al, through X-ray crystallography . They also determined the absolute configuration of (+)- O -methylanhalonidine ( 19 ).…”

Section: Biosynthesis Of the Alkaloids From The Lophophora Genusmentioning

confidence: 99%

“…They also determined the absolute configuration of (+)- O -methylanhalonidine ( 19 ). It was assumed that O -methylpellotine ( 20 ) has the same configuration . The optical rotation and the absolute configuration of 2 and the remaining phenolic THIQs have yet to be identified, as these compounds appear to rapidly epimerize during the isolation procedure .…”

Section: Biosynthesis Of the Alkaloids From The Lophophora Genusmentioning

confidence: 99%

“… a (i) Tyrosine/ l -DOPA decarboxylase, (ii) 4-hydroxyphenylpyruvate dioxygenase, (iii) Fe 2+ /α-ketoglutarate oxygenase, (iv) O -methyltransferases. ,− The absolute configurations have been determined for (−)- 4 and (−)- 5 …”

Section: Biosynthesis Of the Alkaloids From The Lophophora Genusmentioning

confidence: 99%

“…N -Acylation of 53 and subsequent ring closure led to both the 6,7-methylenedioxy-8-methoxy and 7,8-methylenedioxy-6-methoxy substitution pattern of the arene, with the latter, (±)- 4 , being the major product . Brossi et al prepared the optically active forms of ( S )-(−)- 4 ([α] D −56.3) and ( S )-(−)- 5 ([α] D −47.3) from the racemic substrates, in order to determine the absolute configuration of the naturally occurring products . Starting from (±)- 19 , they dealkylated the 7- and 8-methoxy groups, obtaining catechol 55 , which following N -protection was then converted to 7,8-methylendioxy substrate 57 .…”

Section: Chemical Synthesis Of Thiqs From the Lophophora Genusmentioning

confidence: 99%

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The Alkaloids from Lophophora diffusa and Other “False Peyotes”

et al. 2021

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Commonly, false peyote refers to Lophophora diffusa. However, several other unrelated cacti go by this colloquial name. They either resemble “true” peyote, Lophophora williamsii, or are found in similar habitats. To date, over 40 different alkaloids have been isolated from the Lophophora genus. Of these, only the pharmacological actions of mescaline (1) have been extensively investigated. The major alkaloid in L. diffusa is pellotine (2), a tetrahydroisoquinoline (THIQ), which was briefly marketed as a sleeping aid around the beginning of the 20th century, following reports of its hypnotic properties in humans. Pharmacological experiments with the Lophophora THIQs were performed at the turn of the 20th century, whereas the chemical synthesis was not realized until several decades later. The biosynthetic pathways of the main Lophophora alkaloids were reported at the end of the 1960s. In this review, the relationship of the different “false peyotes” to L. williamsii, in regard to their alkaloid content, the bio- and chemical synthesis of the most relevant alkaloids, and their corresponding pharmacology will be outlined and discussed.

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Hydrogen Chloride

Breton

Kropp

2001

Encyclopedia of Reagents for Organic Synthesis

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New synthesis and absolute configuration of tetrahydroisoquinoline cactus alkaloids

Cited by 25 publications

References 0 publications

Alkaloids of the Cactaceae — The Classics

Alkaloids of the Cactaceae — The Classics

The Alkaloids from Lophophora diffusa and Other “False Peyotes”

Hydrogen Chloride

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