Convenient Syntheses of 3-Aryl-3,4-Dihydroisocoumarins

Abstract

A convenient method for the synthesis of naturally occurring 3,4-dihydroisocoumarins by judicious use of Friedel-Craft acylation, regioselective formylation and oxidative cyclisation reactions is described. O-methylated analogues of montroumarin and thunberginols C and D and have been synthesised using 3,5-dimethoxyphenylacetic acid as a starting material. Furthermore, the starting material 3,5-dimethoxyphenylacetic acid was synthesised by a route involving an oxidative Nef reaction.

Synthesis of Functionalized Indolines and Dihydrobenzofurans by Iron and Copper Catalyzed Aryl C–N and C–O Bond Formation

“…37 3,5-Dimethoxy-1-[(E)-2′-nitrovinyl]benzene. 38 3,5-Dimethoxy-1-[(E)-2′-nitrovinyl]benzene was synthesized as described for 3-methoxy-1-[(E)-2′-nitrovinyl]benzene using 3,5-dimethoxybenzaldehyde (0.350 g, 2.10 mmol). The residue was recrystallized from diethyl ether which gave 3,5-dimethoxy-1-[(E)-2′-nitrovinyl]benzene (0.357 g, 81%) as a yellow solid.…”

“…Mp 81−83 °C (lit. 38 1-[(E)-2′-Nitrovinyl]-3,4,5-trimethoxybenzene. 37 1-[(E)-2′-Nitrovinyl]-3,4,5-trimethoxybenzene was synthesized as described for 3-methoxy-1-[(E)-2′-nitrovinyl]benzene using 3,4,5-trimethoxybenzaldehyde (1.00 g, 6.00 mmol).…”

“…Purification by flash column chromatography (petroleum ether/ethyl acetate, 7:3) gave 4-chloro-3-nitro-1-[(E)-2′-nitrovinyl]benzene (0.620 g, 26%) as a yellow solid. (38), 136 (95), 115 (38), 101 (48), 89 (41), 75 (54); HRMS (EI) calcd for C 8 H 5 35 ClN 2 O 4 (M + ) 227.9938, found 227.9929. 1′-(3-Methoxyphenyl)ethyl-2′-amine.…”

“…Spectroscopic data were consistent with the literature. 48 (17), 164 (38), 151 (100), 107 (17), 91 (48).…”

“…Purification by flash column chromatography (petroleum ether/ethyl acetate, 1:1) gave 1-(methanesulfonyl)-5-methoxyindoline (2e) (0.041 g, 73%) as a colorless oil. IR (neat) 2932, 1489, 1343, 1157, 1030, 818 cm −1 ; 1 H NMR (400 MHz, CDCl 3 ) δ 2.81 (s, 3H), 3.12 (t, J = 8.5 Hz, 2H), 3.78 (s, 3H), 3.97 (t, J = 8.5 Hz, 2H), 6.72 (dd, J = 8.8, 2.5 Hz, 1H), 6.79 (d, J = 2.5 Hz, 1H), 7.32 (d, J = 8.8 Hz, 1H); 13 C NMR (101 MHz, CDCl 3 ) δ 28.4 (CH 2 ), 33.9 (CH 3 ), 50.7 (CH 2 ), 55.7 (CH 3 ), 111.6 (CH), 112.8 (CH), 115.1 (CH), 133.1 (C), 135.4 (C), 156.8 (C); MS (EI) m/z 227 (M + , 45), 148 (100%), 133 (69), 117 (38), 77 (33); HRMS (EI) calcd for C 10 H 13 NO 3 S (M + ) 227.0616, found 227.0617.…”