Some Esters Based on p-Chloromethylbenzoyl Chloride

Paracyclophanes: Extending the Bridges. Synthesis

“…This was esterified via the corresponding acid chloride to 12, which after catalytic hydrogenation over Pd/C, LAH reduction and bro-mination gave the dibromide 13. Both 12 [25] and 13 [26] have been described in the chemical literature before, but the routes presented in Scheme 3 gave far superior yields. Scheme 3.…”

“…The compound has been described in the lit. [36] 1-(Bromomethyl)-4-(3Ј-bromopropyl)benzene (13): A solution of the saturated diester (19.07 g, 85.8 mmol) in anhydrous diethyl ether (250 mL) was added dropwise to a suspension of lithium aluminum hydride (7.0 g, 0.18 mol) in diethyl ether (500 mL) at a rate to keep the solvent gently boiling. After the addition was complete, the mixture was heated to reflux for 1 h, and then cooled to room temp.…”

Synthesis of Am80 (Tamibarotene) Prodrug Candidates, Congeners and Metabolites

“…Precipitated crystals were collected as above to give 21 (47.9 g, 95%) as a colorless powder, mp 286-290°C [lit. mp 286-289°C (HOAc) 19) ]. IR (KBr) cm (99%D, 300 mL) in a vessel (500 mL, Ace Glass, globular shape), and it was purged with hydrogen gas (1 atm) and sealed, and then heated in an oil bath (130°C) for 64 h. After termination of the reaction (checked by NMR of the aliquot in D 2 O), the mixture was filtered through a Celite bed under reduced pressure, and the filtrate was distilled to recover D 2 O (247 mL, 82% at 57-58°C/120 mmHg).…”

Neue Erkenntnisse Uber Die Chemie Der [M.N]PARACYCLOPHANE

“…Auch durch mehrmaliges Wiederholen der Cyclisierung von 41 mit 38, konnte die in der Literatur ' angegebene Ausbeute von 91% nicht erreicht werden. Im Vergleich dazu wurde das als Vorstufe schon vorhandene l,4-Bis-(3'-bromethyl)-benzol 31^ ( 42) mit 1,4-Bis-(mercaptomethyl)-benzol (36) unter den gleichen Versuchsbedingungen in 63%iger Ausbeute in 43 umgesetzt.…”

“…MS m/z (%): 308(M + , 100), 291 (15), 290 (36), 263 (17), 185 (12), 175 (15), 148 (18), 145 (25), 131 (52), 117 (35), 105(60), 104(41), 91 (53). 3.88 (s, 3H, 22-H), 6.62 -6.68 (m, 4H, 16-H, 17-H, 19-H, 20-H), 6.69 (d, IH, J 9 10 = 7.7 Hz 10-H), 6.79 (dd, IH, J 79 = 1.7 Hz, 9-H), 7.32 (d, IH, 7-H).…”