Preparation of 4-Retinamidophenyl- and 4-Retinamidobenzyl-C-glycosyl and C-Glucuronosyl Analogues of the Glucuronide of 4-Hydroxyphenyl-Retinamide as Potential Stable Cancer Chemopreventive Agents

Carbohydrate-Based Macrolides Prepared via a Convergent Ring Closing Metathesis Approach: In Search for Novel Antibiotics

“…Treatment of 6 with hydrogen bromide in acetic acid led to selective conversion of the anomeric acetate into a bromide, providing a good leaving group for Grignard substitution with phenylmagnesium bromide. 20 to neighboring group participation (J H1-H2 ) 10.1 Hz). 21 Reductive cleavage of the thiophenyl group with freshly prepared Raney nickel under inert atmosphere, 22 followed by methanolysis of the acetates, led to 1,5-anhydro-D-glucitol 13 in 56% overall yield from 6.…”

“…Treatment of 6 with hydrogen bromide in acetic acid led to selective conversion of the anomeric acetate into a bromide, providing a good leaving group for Grignard substitution with phenylmagnesium bromide . Reacetylation of the deprotected hydroxyl groups and subsequent crystallization of the crude product from 2-propanol furnished 7 .…”

“…The solvent was removed under reduced pressure, and the residue was chromatographed (n-pentane-acetone 85/15) to afford 3 (0.735 g, 64%) and 17a (0.169 g, 15%) as colorless oils. Data for 3: R f 0.20 (n-pentane-acetone 85/15); [R] 20 D -16.2 (c 1.07, CHCl 3 ); IR (film) 3420, 2976, 2932, 2905, 2867, 2834, 1145, 1088, 1070 cm -1 ; ES-MS (m/z) 41 ( 38), 73 (20), 88 (75), 121 (100), 147 (11), 207 (10), 308 (<1, M + ); 1 H NMR (500 MHz, CDCl 3 ) δ 7.38 (2H, br d, J ) 6.5 Hz), 7.33 (3H, m), 5.89 (1H,ddd,J ) 5.6,10.4,17.2 Hz), 5.27 (1H,dd,J ) 1.6,17.2 Hz), 5.18 (1H, dd, J ) 1.3,10.4 Hz), 4.14 (1H, d, J ) 9.5 Hz), 4.08 (1H, ddt, J ) 1.3,5.6,12.9 Hz), 4.04 (1H, ddt, J ) 1.3,5.6,12.9 Hz), 3.76 (1H,dd,J ) 4.9,10.4 Hz), 3.72 (1H,dd,J ) 4.4,10.4 Hz), 3.68 (3H, s), 3.66 (1H, dt, J ) 1.9, 9.2 Hz), 3.56 (1H, p, J ) 4.7 Hz), 3.28 (1H, t, J ) 8.9 Hz), 3.08 (1H, t, J ) 9.2 Hz), 2.97 (1H, br d, J ) 1.9 Hz), 2.94 (3H, s); 13 C NMR (125 MHz, CDCl 3 ) δ 139.1,134.4,128.3,128.2,127.5,117.4,87.7,85.9,81.6,77.9,…”

Synthesis and preliminary chemotherapeutic evaluation of the fully C-linked glucuronide of N-(4-hydroxyphenyl)retinamide

“…Starting from readily available δ-D-gluconolactone (8), hydroxyl protection using mild conditions with MOMCl and diisopropylethylamine gives the protected lactone 9 (Scheme 1). Olefination using Petasis reagent 16,17 gives the known exoanomeric methylene sugar 10 in good yield.…”

A Convergent Ring-Closing Metathesis Approach to Carbohydrate-Based Macrolides with Potential Antibiotic Activity

“…Glucopyranosyl bromide 1c ( J H1 - H2 = 4.0 Hz) was converted to 7a ( J H1 - H2 = 9.9 Hz) following a literature procedure . Zemplén methanolysis (→ 7b ), introduction of the 4,6- O -benzylidene acetal (→ 8a ), methylation (→ 8b ), and finally, 10-CSA-mediated solvolysis of the acetal furnished scaffold 9 (36% from 1c ).…”