Quinolines Formation by Condensation of Heteroaromatic Ketones and 2‐Aminobenzophenones under MW Irradiation

Abstract

Microwave (MW) irradiation facilitated synthesis provides fast, safe, simple, and green reaction conditions. MW irradiation of 2-aminobenzophenones with heteroaromatic ketones afforded quinolines via Friedlander condensation in high yields with intact halogen substituents for further modifications.

Facile Synthesis of Nitrogen-Doped [(6.)m8]nCyclacene Carbon Nanobelts by a One-Pot Self-Condensation Reaction

“…The phenyl or 4- tert -butylphenyl substituents on the eight-membered rings tilt away from the belts, while the 4- n -butylphenyl groups in the optimized geometries of 3 and 4 are almost perpendicular to the anthracene units. The average dihedral angles at the eight-membered rings are 70, 70, 74, and 83°, respectively, which are close to those of most reported structures containing [1,5]­diazocines (about 72–75°), − implying a slightly strained structure in these belts. The benzene, naphthalene, and anthracene units in 1 – 3 are slightly bent outward, while the anthracene moiety in 4 is slightly bent inward.…”

“…In one of our experiments, we obtained 6,12-diphenyldibenzo­[1,5]­diazocine by accident from a refluxed toluene solution of 2-aminobenzophenone and diphenyl phosphate (DPP) with more than 80% yield (Figure b). This one-pot self-condensation cyclization can be dated back to 1896, and it has been achieved under various reaction conditions with excellent yields. − The [1,5]­diazocine can be regarded as a 1,5-nitrogen-doped COT, and its X-ray structure clearly reveals a tub-shaped structure with a bending angle of about 75° (Figure b), which is desirable for the formation of nanobelts containing eight-membered rings. Inspired by this highly efficient self-condensation cyclization reaction and Gleiter’s strategy, we expected that similar reactions starting from precursors carrying bis­( o -aminobenzophenone)­s could give [1,5]­diazocine-containing nanobelts in one pot.…”

Catalytic Asymmetric Synthesis of Inherently Chiral Saddle‐Shaped Dibenzo[b,f][1,5]diazocines†

“…To unravel the mechanism of this reaction, particularly the role of the corresponding aniline co‐catalyst, several experimental mechanistic studies were performed (Scheme 2). It has been documented that under harsh conditions, 2‐benzoyl aniline 3a can undergo dehydrative dimerization, yielding the corresponding dibenzo[1,5]diazocine 2a ; [ 18 ] however, no 2a was detected when 3a was treated with CPA catalyst at room temperature (Scheme 2, a). The enantioselective cyclocondensation reaction of the fluorine‐containing isocyanate 1g , catalyzed by CPA A5 and aniline 3g , was carefully monitored by 19 F NMR (Scheme 2, b).…”

Synthetic strategies and diversification of dibenzo[1,5]diazocines

“…The products 2c and 2i were formed rapidly in the yields of 89 and 80%, respectively (Scheme 4a). 49,50 Alternatively, switching DPP to P 2 O 5 , substrate 12c transformed to 2j in 98% yield after mild heating for two hours (Scheme 4b). 51 In a similar way, the use of Ca(OTf ) 2 /Bu 4 NPF 6 also assists in the conversion of 12d,e into 2k,l in 83 and 79% yields, respectively (Scheme 4c).…”