Efficacious methyl-labeled (+-)-camphor synthesis

Abstract

described above to give 0.08 g (20%) of cts-diol 1 and 0.10 g (24%) of frons-diol 4.Preparation of Benzyl Ether 19.-A dispersion of 53% sodium hydride in mineral oil (3.24 g of sodium hydride, 0.135 mol) was washed with three 50-ml portions of dry pentane under nitrogen.After the final wash the residual pentane was evaporated in vacuo and 60 ml of dimethyl sulfoxide was added dropwise under nitrogen. The resulting solution was stirred at room temperature for 0.5 hr. To this solution was added dropwise over a period of 5 min a solution of 13.70 g (0.090 mol) of 1632 j [a]26d -26.26°( c 2, CHCls)! in 40 ml of dimethyl sulfoxide, and the mixture was stirred at room temperature for 10 hr. To this mixture was added 17.0 g (0.135 mol) of benzyl chloride with stirring over a period of 0.5 hr. The reaction mixture was stirred for 1.0 hr, diluted with 350 ml of ice water, and extracted with pentane. The combined extracts were washed with brine, dried, and concentrated to give 26.87 g of a pale yellow oil from which crystallized 0.46 g of transstilbene. The remaining material was distilled to give 14.55 g (67%) of 19: bp 115-116°( 0.25 mm); [ ]%> -21.79°(c 3.5, CHCla); ir (CC14) 3090 (C=CH), 3050 (aromatic CH), 1640 (C=C), 1380 and 1360 (yem-dimethyl), 1055 (CO), 897 (C=

Formation of synthetically useful camphor derivatives: mechanistic aspects

“…49-~euteriocamphor (26) (16,19,(24)(25)(26)) and 8-deuteriocamphor (18) (19,26,27) were synthesized by reducing 9-bromocamphor (2) and 8-bromocamphor (4), respectively, with Bu3SnD/AIBN. Subsequent brornination ( l c ) then provided the corresponding 3,3-dibromo derivatives.…”

Rearrangement of .alpha.-bromocamphoric anhydride. 2. Competitive mechanisms in the formation of laurolenic acid

“…NMR like that of 17 without the 6.20 and 6.48 AB quartet; mass spectrum m/e 154 (5), 153 (5), 110 (30), 109 (93), 108 (22), 95 (100), 94 (58), 93 (19), 69 (21), 67 (15), 55 (22). L(-)-2,8-Epoxybornane (30).…”

“…Excess hydride was destroyed by sequential addition of 4.3 ml of water, 4.3 ml of 15% NaOH, and 12 ml of water. NMR r 6.20 and 6.48 (AB,J = 11 Hz, 2 H), 6.43 (m, 1 H), 6.98 (s, 2 H, exchanges with D20), 9.07 (s, 3 ), 9.12 (s, 3 H); mass spectrum m/e 152 (6), 109 (16), 108 (100), 95 (67), 94 (33), 93 (30), 67 (19), 55 (22).…”

“…The 5:1 and 4:1 cyclohexane-ether fractions afforded 6.61 g (85%) of a mixture of 19 and 21, mp 90-94 °C, the former preponderant [ca. 11:1 estimated from the result of the oxidation described below or from integration of the 2-H resonances at 5.20 (21) and 6.37 (19) in the spectrum of the corresponding d2 sample]. Recrystallization of an early fraction from ether-pentane afforded an analytical sample of 19 as white rosettes: mp 100.2-100.8 °C; [«]27D +16.8°(c 1.00); IR (CHCI3) 3610, 3500 (broad), 1715 cm"1; NMR 2.03-2.20 and 2.57-2.88 (m, 5 H), 5.28 and 5.78 (AB, J = 11.5 Hz, 2 H), 6.37 (m, 1 H), 8.98 (s, 3 H), 8.98 (48%) of the 8-monomesitoate.…”

ChemInform Abstract: Constituents of the Essential Oil of Strobilanthes auriculatus.

“…For structure elucidation we saponified 22 to give the diol 31. Both 8-(31) and 9-hydroxyisoborneol (35) have been synthesized previously in their optically active forms [6][7][8][9], but though there were some 'H NMR data p u b l i~h e d '~~) we wanted to confirm the unusual structure of 22. Therefore we repeated the reaction sequence described in ref.…”