New Retinoid Analogs from δ-Pyronene, a Natural Synthon

Abstract

δ‐Pyronene (1), a readily available terpenic synthon, is an excellent raw material for the preparation of numerous terpenic intermediates. Original retinoid analogs such as “iso”‐retinyl acetate (5), “iso”‐retinal (6) and ethyl “iso”‐retinoate (7), in which the cyclogeranyl moiety is functionalized in an unusual position, were prepared from δ‐pyronene.

Clickable Vitamins as a New Tool to Track Vitamin A and Retinoic Acid in Immune Cells

“…1 H NMR (400 MHz, CDCl 3 ) δ 9.49 (s, 1H), 6.39 (d, J = 5.9 Hz, 1H), 5.27 (d, J = 5.9 Hz, 1H), 3.38 (s, 6H), 1.85 (s, 3H); 13 C NMR (101 MHz, CDCl 3 ) δ 194.4, 146.7, 141.5, 99.1, 52.5, 9.5. Spectroscopic data are in agreement with those reported ( 28 ).…”

“…Wittig salt ( 1 in scheme 1 ) was coupled with aldehyde ( 2 in scheme 1 ) to make the protected retinal analogue RE-click in 8% yield. Aldehyde ( 2 in scheme 1 ) was synthesized following a literature procedure, which can be found in scheme 2 ( 28 ). The poor yield is a result of several purification steps, which were required to separate the product from the unreacted aldehyde 2 and the facile deprotection of the acetal group under acidic conditions.…”

Biomimetic Synthesis of Fused Polypyrans: Oxacyclization Stereo- and Regioselectivity Is a Function of the Nucleophile

“…Our studies began with synthesis of the 1,4-diepoxide precursor from the known dienyl alcohol 1 (Scheme ), obtained from isoprene in three steps. , The alkenes were sequentially epoxidized, first with hydroxyl-directed Sharpless asymmetric epoxidation to 2 , , followed by the asymmetric epoxidation method developed by Shi for isolated alkenes . As we had earlier observed that a carbonyl group was required as a terminating nucleophile in tandem endo -selective oxacyclizations, the primary alcohol of the resulting 1,4-diepoxide 3 was derivatized as the tert -butyl carbonate to provide the substrate 4 in 64% overall yield (three steps).…”

Synthetic Studies towards the Development of Psoralen-Acidic Retinoid Conjugates and Hybrids

“…Aldehyde 16 could be also prepared directly from chloride 14, though in 35% yield, by treating the latter with the system K 2 HPO 4 /KH 2 PO 4 /NaBr in anhydrous dimethyl sulfoxide 17 at 80 °C for 12 hours. Furthermore, oxidation of aldehyde 16 with oxone 18 in N,N-dimethylformamide, at 45 °C for two days, provided the corresponding carboxylic acid 18 in 73% yield.…”