Construction of Nitrated Benzo[3.3.1]bicyclic Acetal/Ketal Core via Nitration of o-Carbonyl Allylbenzenes

Abstract

Intramolecular annulation of o-carbonyl allylbenzenes was achieved to construct novel nitrated [6,6,6]tricycles having an acetal or ketal motif in good yields. The expeditious one-step nitration route provides 4 or 5 new bond formations, including 2 or 3 C-N bonds and 2 C-O bonds. The structural framework of benzobicycle [3.3.1] is confirmed by X-ray crystallographic analysis. A plausible mechanism is proposed.

Antiproliferation- and Apoptosis-Inducible Effects of a Novel Nitrated [6,6,6]Tricycle Derivative (SK2) on Oral Cancer Cells

“…SK2 (MW = 292.1059), a nitrated [6.6.6]tricycle-derived compound containing an n-butoxy group, was prepared as previously described [11]. A representative synthetic procedure for SK2 is as follows: HNO 3 (97%, 0.5 mL) was mixed with a solution of 2-allyl-3-n-butoxybenzaldehyde (218 mg, 1.0 mmol) in H 2 SO 4 (98%, 2 mL) at 25 • C. Subsequently, they were stirred at 80 • C for 24 h. After dilution with water (10 mL), they were extracted with CH 2 Cl 2 (3 × 20 mL).…”

“…Using this benzo-fused dioxabicyclo [3.3.1]nonane core, we had developed a novel nitrated [6,6,6]tricycle-derived compound containing an n-butyloxy group, namely, SK2 [11]. SK2 possesses an N-O bond similar to the O-O bond, which is prone to chemical cleavage [12] and forms a free-radical structure.…”

Trifluoroacetic Anhydride Mediated One-Pot Synthesis of 1-Aryl Isochroman-3-ones via the Carboxy-Pictet–Spengler Reaction

“…Among these synthetic variations toward heteroatom-Pictet–Spengler-type reactions, to the best of our knowledge, only a few early examples on the generation of 1-substituted isochromans via the synthetic route have been reported. − On the basis of the above recorded observations for Pictet–Spengler-type reactions and the ongoing effort to emphasize the synthesis of oxygen-containing benzocycles, − herein, we present an efficient, one-step synthetic route toward 1-aryl isochroman-3-ones 3 via a carboxy-Pictet–Spengler reaction of oxygenated arylacetic acids 1 with arylaldehydes or ketones 2 in the presence of inexpensive commercially available (CF 3 CO) 2 O (trifluoroacetic anhydride, TFAA) via intermolecular (4 + 2) annulation. In eq 2 (Scheme ), only 2 equiv of trifluoroacetic acid (TFA, a byproduct) is generated from the hydrolysis of TFAA with the in situ formed H 2 O.…”

CuI Mediated One-Pot Cycloacetalization/Ketalization of o-Carbonyl Allylbenzenes: Synthesis of Benzobicyclo[3.2.1]octane Core

“…Continuing our research on synthetic applications of o -carbonyl allylbenzenes, herein, we present a one-pot copper-catalyzed synthesis of a benzofused bicyclo­[3.2.1]­octane core from o -carbonyl allylbenzenes, as shown in Scheme . This intramolecular one-pot cycloacetalization or -ketalization reaction proceeds under mild conditions and affords the products in high yields with high reaction efficiency.…”

“…This intramolecular one-pot cycloacetalization or -ketalization reaction proceeds under mild conditions and affords the products in high yields with high reaction efficiency. According to preliminary results, three kinds of o -carbonyl allylbenzenes 2 , 4 , and 5 were easily prepared from 3-hydroxy­benzaldehyde ( 1a ) and isovanillin ( 1b ) by a series of facile functional group transformations, as summarized in Scheme .…”