N-Propyl esters

To a solution of 4 g of sodium in 200 ml of n-propanol is added 39 g of homovanillic acid-n-propyl ester (boiling point 160°C to 162°C/4 mm Hg) and the mixture is concentrated by evaporation under vacuum. After dissolving the residue in 200 ml of dimethylformamide and the addition of 0.5 gof sodium iodide, 26.2 g of chloracetic acid-N,N-diethylamide are added drop-wise with stirring at an internal temperature of 130°C, and the mixture is further heated at 130°C for three hours. From the cooled reaction mixture the precipitated salts are removed by filtering off with suction. After driving off the dimethylformamide under vacuum, the product is fractionated under vacuum, and 44.3 g of 3-methoxy-4-N,N-diethylcarbamido-methoxy phenyl acetic acid-n-propyl ester are obtained as a yellowish oil of boiling point 210°C to 212°C/0,7 mm Hg,... 

Acetic acid, n-propyl ester, see Propyl acetate... 

During work on a series of aspartyl dipeptides containing ACC 71 (vide supra, Eq. (28), Sect. 4) at the carboxyl terminus, it was reported that dispartame Asp-ACC-OMe had a distinct sweet taste [302] and that the corresponding n-propyl ester had 250-300 times the sweetness of sucrose [303]. However, replacement of phenylalanine by 2,3-methanophenylalanine gave tasteless analogues of aspartame [293, 304], and some dimethyl-ACC 214 (methanovaline) and tri-methyl-ACC 215 aspartame analogues [Asp-(Me)n-ACC-OMe] have a bitter taste. These taste properties, which depend on the number and position of the methyl substituents, have been explained on the basis of topochemical models thus, a L-shaped conformation of the dipeptide is necessary for sweet taste, Eq. (86) [3051. 

Hydroxypyridine, available from pyridylpyridinium chloride hydrochloride, is the substrate for diodone (95) and its n-propyl ester, propyliodone. Both compounds are used as... 

The naturally occurring amino acids are very polar, and cannot be separated as the free compounds by GC at a temperature below decomposition. If the polar groups in the molecule are chemically modified to produce a more volatile derivative a suitable temperature is then possible. Weinstein (25) reviews all the various derivatives which may be formed from amino acids and the GC conditions necessary to separate them. In actual practice only three derivatives are in popular use. These include the N-heptafluorobutyryl n-propyl ester derivatives, the N-trimethyl-silyl ether derivatives, and the n-trifluoroacetyl n-butyl ester derivatives. 

Raw Materials Sodium Homovanillic acid n-propyl ester ... 

Roberts et al. have observed the unusual fragmentation of loss of formaldehyde in methyl esters of ortho-substituted ferrocenyl-benzenes 172). This novel fragmentation of loss of aldehyde has also been observed by Lupin et al. for methyl, ethyl, and n-propyl esters of ortho-substituted ferrocenyl benzenes as well as for methyl esters of alkenyl ferrocenes 134). The ortho effect, in a rearrangement depicting a six-membered transition state, has been proposed by Bursey et al. to explain this fragmentation, but it is more likely that the metal atom plays an important role, possibly with the migration of the methoxyl group to the metal 134). 

The (25) absolute configuration and enantiomeric purities (up to 99 % ee) of the crude amino acids 37 were readily determined by GC comparison (using a chiral capillary column) of their (jV-trifluoroacetyl)-n-propyl esters with those of racemic and enantiomerically pure authentic samples and were further supported by chiroptic comparison. 

Data were also obtained by this method for the solid states for the methyl ester of 2,4-D, the n-propyl ester of 2,4,5-T, and the butyl ester (liquid) of 2,4-D. The results are shown in Table III. These data were fitted by the least squares method to the Clausius-Clapeyron equations given in footnotes to Table III. These equations were used to estimate the vapor pressures at several temperatures, including the melting point. In Table IV, these are compared with estimates from other sources. Jensen s unpublished data with the Knudsen method compare favorably with those reported in this work, but the published values obtained by other methods are larger. 

Determination of the composition of different oils and fats is a very common application of the GC analysis of fatty acids. The samples under analysis are usually hydrolysed first and free fatty acids are esterified. Kleiman et al. [138] used the methanol—BF3 method for determining acyl groups in oils. Barnes and Holaday [139] started directly with ground peanuts when analysing the composition of their fats. After hydrolysis for 8 min by heating at 80°C with a methanolic solution of NaOH they carried out the esterification with 10% of methanol—BF3 at 95°C for 5 min. n-Propyl esters were utilized for the analysis of fatty acids in soaps [140]. After evolving fatty acids with the aid of orthophosphoric acid, the esters were prepared by heating with /7-propanol at 90°C for 2 min. 

Fig. 5.15. Gas chromatogram of N-acetyl-n-propyl esters of 17 amino acids. Conditions glass column, 106 cm X 3 mm I.D., packed with a mixture (1 1) of 0.7% Carbowax 6000 on Chromosorb G (80— 100 mesh, HP) and 0.7% Carbowax 6000 plus 0.05% tetracyanoethyl pentaerythritol on the same support nitrogen flow-rate, 30 ml/min temperature programme, 6°C/min, 100-240°C. (Reproduced from J. Chromatogr., 36 (1968) 42, by courtesy of J.R. Coulter.)...

Hasegawa et al. reported another example of a [2 + 2] asymmetric transformation in a chiral crystal (Scheme 5) [13]. Ethyl 4-[2-(pyridyl)ethenyl] cinnamate 8b crystallizes in a chiral space group P2 2 2 and upon irradiation yields a chiral dimer with 92-95% ee however, the methyl and n-propyl esters (8a and 8c) crystallized in achiral space groups. 

SYNS ACETATE de PROPYLE NORiYLAL (FRENCH) ACETIC ACID, n-PROPYL ESTER 1-ACETOXY-PROPANE OCTAN PROPYLU (POLISH) PROPYL ACETATE 1-PROPYI. ACETATE PROPYLESTER KYSELINY OCTOVE... 

SYNS GALLIC ACID, PROPYL ESTER NIPA 49 NIPAGALLIN P PROGALLIN P n-PROPYL ESTER of... 

TRIHYDROXYBENZOIC ACID PROPYL GALLATE n-PROPYL-3,4,5-TRIHYDROXYBENZOATE TEXOX PG 3,4,5-TRim DROXYBENZENE-l-PROPYLCARBOXYLATE 3,4,5-TRIHYDROXY-BENZOIC ACID, n-PROPYL ESTER... 

ACETIC ACID PHENYLMETHYL ESTER see BDXOOO ACETIC ACID-2-PROPENYL ESTER see AFU750 ACETIC ACID, n-PROPYL ESTER see PNC250 ACETIC ACID, S.3MARIUM SALT see SAROOO ACETIC ACID, SODIUM SALT see SEG500 ACETIC ACID, TRIANHYDRIDE with ANTIMONIC ACID see AQJ750... 

The optically active arsinous acid esters 128-134 and the arsinthious acid ester 135 have been used to prepare optically active tertiary arsines (Table 7). When the arsine sulphide 136 was heated in benzene with n-butyl or -propyl bromide, ethyl bromide was eliminated and there was a reversal in the sign of the rotation, which was attributed to the formation of the inverted n-butyl and n-propyl esters of (p-carboxyphenyl)phenyl-arsinthious acid, 137a and 137b, respectively (equation 18) . 

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