Phenylpropiolic acids. Part V. Self-condensation of m-alkoxy- and 3:4-dialkoxy-phenylpropiolic acids

Baddar, F. G.; Fahim, Hussein A.; Galaby, Mahmoud A.

doi:10.1039/jr9550000465

Cited by 4 publications

(6 citation statements)

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“…The starting material, 3-nitrobenzoic acid, was first converted into 3-bromo-5-nitrobenzoic acid (83%) by direct bromination under strongly acidic conditions using silver sulfate in concentrated sulfuric acid. 19 Subsequent reduction of the nitro group with Sn powder and hydrochloric acid gave the corresponding amino compound in 88% yield, which was transferred via the diazonium salt to 3-bromo-5-hydroxybenzoic acid (9) in 86% yield. 19 Protective esterification of 9 was carried out with ethanol and concentrated sulfuric acid 20 to obtain 10 in 90% yield.…”

Section: Synthesismentioning

confidence: 99%

“…19 Subsequent reduction of the nitro group with Sn powder and hydrochloric acid gave the corresponding amino compound in 88% yield, which was transferred via the diazonium salt to 3-bromo-5-hydroxybenzoic acid (9) in 86% yield. 19 Protective esterification of 9 was carried out with ethanol and concentrated sulfuric acid 20 to obtain 10 in 90% yield. For affixing of the terminal ethynyl unit to 10, monoprotected trimethylsilylacetylene was used and reacted under palladium catalyzed coupling conditions 21 followed by cleavage of the protecting group.…”

Section: Synthesismentioning

confidence: 99%

“…3-Amino-5-bromobenzoic acid was prepared from 3nitrobenzoic acid by direct bromination and subsequent reduction with Sn-HCl. 19 Crystallization from ethanol yielded 73% solid; mp 222 • C (lit. 19 mp 220-222 • C).…”

Section: Compounds and Materialsmentioning

confidence: 99%

“…3-Bromo-5-hydroxybenzoic acid (9) was obtained from 3amino-5-bromobenzoic acid via diazotation and hydrolysis. 19 Crystallized from water in the presence of charcoal yielded 86% of a light yellow solid; mp 238 • C (lit. 19 mp 238-239 • C).…”

Section: Compounds and Materialsmentioning

confidence: 99%

“…19 Crystallized from water in the presence of charcoal yielded 86% of a light yellow solid; mp 238 • C (lit. 19 mp 238-239 • C).…”

Section: Compounds and Materialsmentioning

confidence: 99%

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Oligofunctional amphiphiles featuring geometric core group preorganization: synthesis and study of Langmuir and Langmuir–Blodgett films

et al. 2005

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Based on the principle of supramolecular preorganization, a new type of oligofunctional amphiphile, of which compounds 1-4 are representative structures, has been designed and synthesized. The typical feature of their structure is a highly rigid and geometrically well-defined central unit composed of ethynylene substituted aromatic spacers with different numbers of amphiphilic segment groups (also of a rigid geometric design) attached to it. The molecules form well-defined Langmuir films when spread from a solution at the air/water interface or when a 10(-4) M aqueous CaCl2 solution was used as the subphase. By analysis of the surface pressure-surface area (pi-A) isotherms, information on the packing behavior and orientation of the amphiphilic molecules depending on the molecular structure could be obtained. Morphological characterization of the dynamic process of monolayer compression at the air/water interface was carried out by Brewster angle microscopy, illustrating several phase states visualized as snap shots. Thin monolayer films produced on a 10(-4) M aqueous CaCl2 subphase can be transferred to a mica solid support by the Langmuir-Blodgett technique. Tapping mode atomic force microscopy reveals a surface topography of the monofilms composed of 1 and 3 that differ in roughness and also in the properties of elasticity, hardness and adhesive strength. X-Ray crystal structure analysis of three relevant intermediate compounds of the synthesis were successfully determined giving an indication of the potential structural features inherent in the new amphiphiles.

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Section: Synthesismentioning

confidence: 99%

Section: Synthesismentioning

confidence: 99%

Section: Compounds and Materialsmentioning

confidence: 99%

Section: Compounds and Materialsmentioning

confidence: 99%

“…19 Crystallized from water in the presence of charcoal yielded 86% of a light yellow solid; mp 238 • C (lit. 19 mp 238-239 • C).…”

Section: Compounds and Materialsmentioning

confidence: 99%

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Oligofunctional amphiphiles featuring geometric core group preorganization: synthesis and study of Langmuir and Langmuir–Blodgett films

et al. 2005

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Double Dehydro‐Diels–Alder Reactions of 1,5‐Dien‐3‐ynes

Fallon

Robinson

Willis

et al. 2010

Chemistry A European J

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Allene towards efficiency: Two new rings, six stereocentres and four CC bonds are generated in synthetically useful yields by double dehydro‐Diels–Alder reactions of readily available 1,5‐dien‐3‐ynes and alkenic dienophiles. Computational studies support a mechanism for this often highly stereoselective process involving two concerted cycloaddition events and a 1,2‐cyclohexadiene intermediate (see scheme).

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