Louisianins A, B, C and D: non-steroidal growth inhibitors of testosterone-responsive SC 115 cells. II. Physico-chemical properties and structural elucidation

A world tour in the name of natural products

BACKGROUND

Names of natural products (NP) are usually given depending on the species of origin, be it a plant, a marine organism or a microbial species. In some cases, names have been given with reference to people, animals, music, foods or places. Many NP refer to countries, cities or specific places such as mountains, deserts, seas and oceans.

PURPOSE

On the basis of NP names, a world tour has been imagined referring to more than one hundred NP with names evocative of over 50 countries and regions.

RESULTS

The world tour goes from UK (britannin) to Italy (vaticanol) in Europe, from Uganda (ugandoside) to Senegal (senegalene, senegalenines) in Africa, from Brazil (brasilin) to Chile (santiaguine) in South America, from Utah (utahin) to Florida (floridanolide) in the US. It includes Central America (mexicanin, panamine) and the Caribbean islands (jamaicin, bahamaolides). It also crosses Alaska (alaskene) and Canada (quebecol, canadaline). The tour continues throughout Asia, from Thailand (thailandine) to China (Chinaldine) and Pakistan (pakistanamine), to finally reaches Oceania with Australia (australigenin) and Vanuatu (vanuatine), among other countries. This virtual journey, without bordure or wall, brings us to the highest mountains (himalayamine), the deepest oceans (pacificins) and the largest deserts (desertomycin).

CONCLUSION

In the current period of COVID-19 pandemia, with restricted opportunities for international travels, this NP name-based virtual journey offers a world tour to learn more from nature and to inspire scientists to contribute to the field of NP discovery and drug design. There are also limitations associated with the use of trivial names for NP. NP names can be further exploited for teaching and learning.

First total synthesis of louisianin A

The first total synthesis of louisianin A, 4-allyl-6,7-dihydro-1-hydroxycyclopenta[c]pyridin-5-one, is achieved from 2-chloro-4-cyanopyridine 5 via seven steps in an overall 24% yield. The key step is a cyclization-decarboxylation sequence toward the formation of a cyclopentenone ring.

Efficient Synthesis of Fused Bicyclic Glutarimides. Its Application to (±)-Alloyohimbane and Louisianin D

[reaction: see text] The reaction of alpha-sulfonyl acetamide 1 with various cyclic unsaturated esters 2 to fused bicyclic glutarimides is reported. Syntheses of (+/-)-alloyohimbane (4) and louisianin D (5) have been accomplished.

Synthesis of louisianin C

The synthesis of louisianin C (3), a member of a small family of 3,4,5-trisubstituted pyridyl natural products, is achieved in six steps and 11% overall yield starting from commercially available 3,5-dibromopyridine. The key step is a fluoride-induced desilylation-cyclization to afford carbinol 12.