PTC = phase-transfer catalysts

HPLC High Performance Liquid Chromatography LHRH Lutenizing Hormone Releasing Hormone PTC Phase transfer catalyst SPPS Solid Phase Peptide Synthesis TFA Trifluoro acetic acid... 

DMAP Dimethylaminopyridine DMTCl Dimethylthiocarbamoyl chloride DETCl Diethylthiocarbamoyl chloride PTC Phase transfer catalyst BINOL Binaphthol... 

Alternative base/solvent couples can be selected among DABCO/DMF [27], Na0H/K2C03/DMF/PTC (phase transfer catalyst), KOH/MeOH [28], DMAP/ NEts/DMTCl [29] and quinoline [30,31]. For optimal results, the choice of the most appropriate couple depends on solubility and acidity issues. The yields are usually from good to excellent, the only exceptions arising when the phenol is excessively hindered or additional acidic protons are present in the molecule. 

LTMP = LiTMP PTC phase transfer catalyst/catalysis... 

PTC (phase-transfer catalyst) benzyltrimethylammonium chloride, benzyltriethyl chloride, or tetrabutylammonium chloride... 

Fig. 12.2 Typical procedures for the preparation of colloidal and supported gold nanopartides (PTC Phase transfer catalyst).

Pr, n-Propyl Py, Pyridine PROPHOS, 1,2-Bis(diphenylphosphino)propane PTA, l,3,5-Triaza-7-phosphaadamantane PTC, Phase-transfer catalyst PTSA, p-Toluenesulfonic acid R, An organic group RAMP, R-(-l-)-Amino-2-(methoxymethyOpyrrolidine Rf, Perfluoroalkyl... 

Other authors have improved the catalytic system by small modifications in the applied protocol. Geller et al. [128] found that the introduction of a PTC (phase transfer catalyst) increased the amount of peroxide derivative in the organic phase, resulting in a faster reaction time (>99% conversion in one hour). Epoxy ketone 91a can be obtained on a multigram scale in 75% yield and 95.5% ee (Scheme 12.17) with 10 w/w% of PLL (poly-L-leucine) in the presence of TBAB (tetra n-butylam-monium bromide) [129]. 

FIGURE 29.15 Synthetic strategy of sulfated or sulfonated geminis (where PTC—phase transfer catalyst). (Reproduced fromZhu, Y.-R, Masuyama, A., Kirito, Y, Okahata, M., J. Am. Oil. Chem. Soc., 68,539-543,1991 Sumida, Y., Masuyama, A., Oki, T., Kida, T., Nakatsuji, Y, Ikeda, L, Nojima, M., Langmuir, 12,3986-3990,1996. With permission.)... 

PTC phase transfer catalyst or phase transfer conditions... 

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