Synthesis of dihydrobenzofurans from phenolic mannich bases and their quaternized derivatives

Guest‐Reaction Driven Cage to Conjoined Twin‐Cage Mitosis‐Like Host Transformation

“…Taken together all the above results and previous reports, [16] the following plausible mechanism (Figure 4) is proposed for this unique guest reaction driven host transformation process: 1) In water, up to 4 molecules of G1 were encapsulated by cage 1, giving rise to a high local concentration of ca. 7.57 M inside the nano-cavity (Supporting Information, Figure S38).…”

Three‐Component Aminoalkylations Yielding Dihydronaphthoxazine‐Based Sirtuin Inhibitors: Scaffold Modification and Exploration of Space for Polar Side‐Chains

“…Most probably, highly reactive and short‐lived quinone methide intermediates were generated. While these quinone methides formed in situ were too unstable to be isolated, they could efficiently be trapped by reaction with thiocyanate ions to yield the desired isolated products . In addition to analytical characterization by NMR and MS spectroscopy, the formation of the desired product 8a was confirmed by X‐ray crystallography (Fig.…”

“…Yield: 7.98 g (98.7%); mp: 74.5°C; 1 H‐NMR (DMSO‐d 6 , 400 MHz): δ = 3.98 (s, 2H, C(9)H 2 ), 7.06 (d, 1H, C(3)H, J = 8.8 Hz), 7.27 (t, 1H, C(6)H, J = 8.0 Hz), 7.43 (t, 1H, C(7)H, J = 8.4 Hz), 7.70 (d, 1H, C(8)H, J = 8.8 Hz), 7.77 (d, 1H, C(4)H, J = 8.0 Hz), 7.94 (d, 1H, C(5)H, J = 8.4 Hz) ppm; 13 C‐NMR (DMSO‐d 6 , 100 MHz): δ = 44.3 (N(CH 3 ) 2 ), 55.4 (C9), 113.0 (C8a), 118.5 (C3), 122.2 (C5, C6), 126.1 (C7), 127.9 (C1), 128.3 (C4), 128.7 (C8), 132.9 (C4a), 155.4 (C2) ppm; FT‐IR (): 3380 cm −1 (w), 3006 cm −1 (w), 2950 cm −1 (w), 1626 cm −1 (s), 1439 cm −1 (m), 1322 cm −1 (m), 1245 cm −1 (s); HRMS (ESI): found 202.1226, calcd. for C 13 H 15 NO [M+H] + m/z = 202.1226 .…”

Dihydronaphthofurans: synthetic strategies and applications

“…63 In a similar manner, dihydronaphthofuran 11b was obtained by the reaction of Mannich bases, Mannich base methiodides, and Mannich base N-oxides derived from naphthols with diazomethane in CH 2 Cl 2 at 3 C for 16-96 h or with dimethylsulphoxonium methylide in DMSO at 20-100 C for 2-48 h in 0-28% yields (Scheme 72). 64 Also, 2,3-dihydronaphtho[1,2-b]furan (156) was obtained in 4-53% yields via the reaction of Mannich bases, Mannich base methiodides, and Mannich base N-oxides derived from 1naphthols with diazomethane in CH 2 Cl 2 at 3 C for 24 h or with dimethylsulphoxonium methylide in DMSO at 60-70 C for 2-16 h (Scheme 73). 64 A simple and general route to the synthesis of 1,2-dihydronaphtho[2,1-b]furans 157, substituted in position 2 by an acyl or aroyl group, starting from phenolic Mannich base methiodides and the carbonyl-stablished sulphonium ylide in CH 3 CN has been developed.…”

“…64 Also, 2,3-dihydronaphtho[1,2-b]furan (156) was obtained in 4-53% yields via the reaction of Mannich bases, Mannich base methiodides, and Mannich base N-oxides derived from 1naphthols with diazomethane in CH 2 Cl 2 at 3 C for 24 h or with dimethylsulphoxonium methylide in DMSO at 60-70 C for 2-16 h (Scheme 73). 64 A simple and general route to the synthesis of 1,2-dihydronaphtho[2,1-b]furans 157, substituted in position 2 by an acyl or aroyl group, starting from phenolic Mannich base methiodides and the carbonyl-stablished sulphonium ylide in CH 3 CN has been developed. The reaction proceeds readily at room temperature for 12 h and usually affords desired products 157 in 65-75% yields (Scheme 74).…”