Laterally substituted symmetric and nonsymmetric salicylideneimine-based bent-core mesogens

• Sonja Findeisen-Tandel,
• Wolfgang Weissflog,
• Ute Baumeister,
• Gerhard Pelzl,
• H. N. Shreenivasa Murthy and
• Channabasaveshwar V. Yelamaggad

Beilstein J. Org. Chem. 2012, 8, 129–154, doi:10.3762/bjoc.8.15

• oxalyl chloride. Following pathway A the condensation of the salicylaldehydes 5a–d with 3-aminophenyl 4-(4-n-dodecyloxy-3-substituted-benzoyloxy)benzoates 6 yielded the final compounds according to [33]. Following pathway B, the salicylidene intermediates 5a–d were reacted with 3-aminophenols to give the

• -hydroxyphenyl 4-n-dodecyloxycinnamate (9), respectively, as sketched in Scheme 5. Compound 9 was obtained by esterification of 2,4-dihydroxybenzaldehyde with 4-n-dodecyloxycinnamic acid, under the same conditions as reported for the salicylaldehydes 5. Mesophase behaviour of the compounds OH 5 and OH 6 The

A novel and facile synthesis of 3-(2-benzofuroyl)- and 3,6-bis(2-benzofuroyl)carbazole derivatives

• Wentao Gao,
• Meiru Zheng and
• Yang Li

Beilstein J. Org. Chem. 2011, 7, 1533–1540, doi:10.3762/bjoc.7.180

• described. The synthesis mainly relies on the ultrasound-assisted Rap–Stoermer reaction of 3-chloroacetyl- (1) or 3,6-dichloroacetyl-9-ethyl-9H-carbazole (4) with various salicylaldehydes 2a–k as well as 2-hydroxy-1-naphthaldehyde (2l) in CH3CN with the presence of PEG-400 as catalyst. The procedure offers

• easy access to benzofuroylcarbazoles in short reaction times and the products are obtained in moderate to good yields. Keywords: 2-benzofuroyl; carbazole; PEG-400; Rap–Stoermer reaction; salicylaldehydes; ultrasound-assisted; Introduction Carbazole, and especially heterocycle-containing carbazole

• ], and which could provide opportunity for the direct construction of 2-benzofuroyl-based compounds through base-mediated reaction of salicylaldehydes with α-haloketones. The synthetic route developed in our laboratory for the preparation of 3-(2-benzofuroyl)carbazoles 3a–k by the Rap–Stoermer reaction

The arene–alkene photocycloaddition

• Ursula Streit and
• Christian G. Bochet

Beilstein J. Org. Chem. 2011, 7, 525–542, doi:10.3762/bjoc.7.61

• photocycloaddition of allenylated salicylaldehydes affords a benzoxepine derivative and an apparent para photocycloadduct (Scheme 40) [104]. The product distribution is dependent on the substitution pattern of the aromatic core. Introduction of bulky tert-butyl substituents at positions 3 and 5 on the aromatic ring

First synthesis of 2-(benzofuran-2-yl)-6,7-methylene dioxyquinoline-3-carboxylic acid derivatives

• Wentao Gao,
• Jia Liu,
• Yun Jiang and
• Yang Li

Beilstein J. Org. Chem. 2011, 7, 210–217, doi:10.3762/bjoc.7.28

• reaction of ethyl 2-chloromethyl-6,7-methylenedioxyquinoline-3-carboxylate (5) with various substituted salicylaldehydes 6a–g as well as 2-hydroxy-1-naphthaldehyde (6h) is described. Substrate 5 was synthesized by the Friedländer condensation reaction of 2-amino-4,5-methylenedioxybenzaldehyde (4) with

• -carboxylic acid derivatives (3a–g) by the reaction of 5 with substituted salicylaldehydes 6a–g. The reaction proceeds via in situ Williamson ether formation followed by ester hydrolysis and intramolecular cyclization (Scheme 2). The procedure uses an inexpensive inorganic base as catalyst under mild reaction

• with various salicylaldehydes 6a–g in the presence of K2CO3 as catalyst in refluxing CH3CN. Acetonitrile was employed in our method because of its low boiling point and leads to a much more convenient workup procedure. Thus, once the Williamson reaction was complete as observed on TLC, we simply

Synthesis of 3-(quinolin-2-yl)- and 3,6-bis(quinolin-2-yl)-9H-carbazoles

• Yang Li and
• Wentao Gao

Beilstein J. Org. Chem. 2010, 6, 966–972, doi:10.3762/bjoc.6.108

• )carbazoles under solvent-free conditions by the reaction of β-nitrovinylcarbazole or bis(β-nitrovinyl)carbazole with salicylaldehydes. In light of these findings, and in view of the prominent role structural diversity plays in medicinal and combinatorial chemistry, we felt that there was a real need for the