Reaction of 2‐Methylenenorbornane with N‐Bromosuccinimide

Abstract

Because of the presence of the bromine atom in cis-l-(2-bromo-3-phenanthryl)-Z-(Z-naphthyl)e-thylene (XI), the upfield shift of H, (Ha3) is much larger than in the corresponding unsubstituted cis-1, 2-diarylethylene.We acknowledge the fact tlydt other co-workers have made similar observations in the course of the last few years. The financial support of the 'Fonds de la Recherche Fondamentale Collective' is gratefully acknowledged. One of us (J.J.R.) exprcsses his gratitude t o the 'Znstitut pour I'Encouragewent de la Recherche Scientafaque duns l'lndustvie el I'Agrirulture' for the award of a fellowship.

Retinoic acid analogs. Synthesis and potential as cancer chemopreventive agents

“…After the addition of 100 mg of THBQ, the product was stored at -5 °C. Preparative high-performance LC (0.8% EtOAc/hexane) gave 1.97 g (48%) of viscous yellow ester 24 as a single isomer to analytical highperformance LC (3% EtOAc/hexane): IR (film) 1695 (C=0), 1600 (C=C), 1580,1390,1350,1240,1150,1040,975,890,840 cm"1; NMR (CDC13) 1.00 (t, J = 8 Hz, 3, Ctf3CH2C), 1.07 (s, 6, C-16 and C-17 CH3), 1.32 (t, J = 6 Hz, 3, CH3CH20), 1.4-1.7 (m, 4, C-2 and C-3 CH2), 2.02 (s, 3, C-19 CHg), 1.9-2.15 (m, 4, C-4 and C-18 CH2), 2.39 (d, J = 1 Hz, 3, C-20 CH3), 4.19 (q, J = 7.5 Hz, 2, COOCH2), 5.78 (s, 1, C-14 C=CH), 6.03-6.40 (m, 4, C-7, C-8, and C-12 HC=CH, C-10 C=CH), 6.94 and 7.06 (dd, J = 15 and 12 Hz, 1, C-ll HC=CH); 13C NMR (CDClg) 13.0 (C-19), 13.5 and 14.0 (C-20, CCHgCHg), 14.4 (OCH2CHg), 19.6 (C-3), 28.0 (CH2CHg), 29.1 (C-16 and C-17), 30.0 (C-4), 34.5 (C-l), 40.1 (C-2), 59.5 (OCHg), 118.8 (C-14), 128.8,129.6, and 130.8 (C-7, C-10 and C-ll), 135.4 and 135.7 (C-5 and C-12), 136.6 and 137.7 (C-6 and C-8), 139.4 (C-9), 152.4 (C-13), 167.0 ppm (C-15); UV Xmaz (EtOH) 351 nm (t 3.37 X 104), 242 (e 8.6 X 103). MS Caled for C^HgA: 342.2559.…”

“…Crystallization from 3 mL of EtOAc yielded 1.08 g (57%) of bright-yellow needles, mp 170-171 °C. The mother liquor was retained for recovery of more product: high-performance LC (reverse phase, 80% MeCN/H20,1 mL/min, 280 nm) fR 9.4 (97%), 3.3 (0.7%), 1.7 min (2%); IR (mull) 3200-2350 (COOH), 1690 (C=0), 1650 (C=C), 1570,1265,1200,1175, 990, 980 cm"1; NMR (CDC13) 0.98 (t, J = 8 Hz, 3, CH2Ctf3), 1.05 (s, 6, C-16 and C-17 CHg), 1.35-1.75 (m, 4, C-2 and C-3 CH2), 2.01 (s, 3, C-19 CHg), 1.9-2.15 (m, 4, C-4 and C-18 CH2), 2.38 (d, J = 1 Hz, 3, C-20 CHg), 5.80 (s, 1, C-14 C=CH), 6.03-6.41 (m, 4, C-7, C-8, and C-12 HC=CH, C-10 C=CH), 7.00 and 7.11 (dd, J = 15 and 11 Hz, 1, C-ll HC=CH); 13C NMR (CDClg) 13.0 (C-19), 13.6 (C-20), 14.1 (C-H2CH3), 19.4 (C-3), 28.0 (CH2CH3), 29.0 (C-16 and C-17), 29.9 (C-4), 34.3 (C-l), 40.0 (C-2), 117.9 (C-14), 129.2 and 129.5 (C-7 and C-10), 131.8 (C-ll), 135.0 and 135.8 (C-5 and C-12), 136.4 and 137.5 (C-6 and C-8), 140.2 (C-9), 155.2 (C-13), 172.8 ppm (C-15); UV Xmal (EtOH) 342 nm (t 4.45 X 104), 244 (e 4.73 X 103). MS Caled for C21H30O2: 314.2246314.…”