Raman spectra and conformations of n-hexadecynoic fatty acids and their potassium salts

Abstract

Raman spectra of n-hexadecynoic fatty acids, CH3(CH2)m-2C ~-C(CH2),_2COOH (with n = 4, 6, 7, 8 and 12, m + n = 16) and their potassium salts were recorded and assigned. The skeletal optical mode (SOM) regions were analysed on using the dispersion curve of the ~'4 (stretch) vibrations of saturated fatty acids. The Iocalised vibrations of the carboxyl-and methyl-terminated sections of the hydrocarbon chains were assigned to the phase ditierences 8 = kzr/m and k~r/n (k = 1, 2 .... ), respectively. Evidence for a ~'4 vibration with 6 = ~r/2m was found. The materials were found to be resistant to chemical decomposition under laser illumination.

Hybrid charge transfer complexes based on archaeal glycolipids wrapping single walled carbon nanotubes

“…2953 cm À1 , the -CH 3 stretching, appearing as a shoulder of the -CH 2 -stretching, is evident in the spectrum of native S-TGD-1. 13 After decoration of the SWNTs by S-TGD-1, the characteristic spectral features of both the SWNTs and of S-TGD-1 are retained.…”

Preparation and Cancer Cell Invasion Inhibitory Effects of C16-Alkynic Fatty Acids.

“…Physicochemical properties of 2 are given here, since they have not been reported in the literature. 3 Undec-10-ynol (12) To a solution of 7 (840 mg, 15.0 mmol) in THF (14 ml) and HMPA (7.0 ml) was added n-BuLi (1.6 M in hexane, 18.8 ml, 30.0 mmol) at Ϫ78°C and the reaction temperature allowed to Ϫ30°C. 1-Bromooctane (11, 3.18 g, 16.5 mmol) was added to the mixture and stirred at room temperature for 12 h. The reaction mixture was poured into aqueous saturated NH 4 Cl and the whole was extracted with Et 2 O.…”

“…The reaction mixture was treated with aqueous saturated NH 4 Cl and the whole was extracted with EtOAc. The EtOAc extract was worked up in the usual manner to give a product (2.23 g), which was purified by silica gel column chromatography (SiO 2 200 g, hexane : EtOAcϭ2 : 1) to afford 10-hydroxy-10-methyldodeca-6, 8 3.37 mmol) in xylene (4.0 ml) was added NaOH (40 mg, 1.00 mmol) and the whole was stirred under reflux for 10 min. After cooling, the mixture was poured into ice-water and the whole was extracted with EtOAc.…”

“…It should be noted that the C 18 -and C 16 -alkynic fatty acids (1)(2)(3)(4)(5)(6) show no cytotoxity to the cancer cells used in the present assay. 1,2) …”

“…Preparation of C 16 -Alkynic Fatty Acids (2-6) Among the C 16 -alkynic fatty acids (2-6), hexadec-8-ynoic acid (2) was synthesized by Levine et al 3) using alkylation of 7-bromoheptanoic acid with 1-nonyne, and hexadec-10-ynoic acid (3) was reported by Arsequell et al 4) as a intermediate for the synthesis of cyclopropane fatty acids. Also hexadeca-8,10-diynoic acid (4) was synthesized by Gunstone and Sykes 5) using a coupling reaction of 1-bromohept-1-yne with 8-nonynoic acid.…”