Propionyl deriv

Three general approaches to the synthesis of pjTido[2,3-d]pyrimi-dines from pyrimidines are available, all of which utilize an appropriately substituted 4-aminopyrimidine. The pyridine ring may be formed by the addition of three (route i), or two (route ii) carbon atoms, or by the intramolecular cyclization of a propionyl derivative (route in). 

Similar ready cyclizations of propionyl derivatives are exemplified by the cyclization of the ester (91) to yield the pyrido[2,3-d]pyrimidine... 

N,N-dimethylamides methyl carboxylates propionyl derivatives acetyl ... 

Conversion of 2 to the highly crystalline oxazolidinone 3 with phosgene has been described by Thornton who has employed this substance as a chiral auxiliary in asymmetric aldol reactions of its N-propionyl derivative. Kelly has also used an oxazoline derived from 3 as a chiral auxiliary in asymmetric alkylation of a glycolate enolate. Oxazolidinone 3 has also been prepared from 2 with diethyl carbonate in the presence of potassium carbonate. The conversion of 2 to the oxazolidinone 3 is accomplished using triphosgene in this procedure because of the high toxicity of phosgene. 

The D-fructose-derived, chiral, nonracemic l,3-oxazin-2-one derivative 260 exerted smooth stereocontrol, resulting in high levels of asymmetric induction and good chemical yields in various synthetic transformations. The chiral fragments 256 and 261 formed in the aldol or a-bromination reactions of the A -propionyl derivative 257 could easily be removed from the parent auxiliary by mild hydrolysis (Scheme 48). The Diels-Alder cyloadditions of the A -acryloyl and A -cinnamoyl derivatives of 260 were also characterized by excellent diasterofacial selectivity <1998T9765>. 

Propionyl derivatives have been studied for the GC of biogenic amines [70], They are very stable and can even be prepared in aqueous medium. Their lipophilicity makes possible their quantitative extraction into ethyl acetate or other organic solvents. The follow-... 

Acetyl derivatives prepared on the column by subsequent injection of anhydride were exploited by Anders and Mannering [346] for the characterization of some steroids by the peak shift technique. The simultaneous injection of an acetic anhydride—propionic anhydride mixture leads to the simultaneous formation of acetyl and propionyl derivatives. Chamberlain et al. [347] applied acetyl derivatives to the analysis of progesterone metabolites in urine. They performed the acetylation of substrates with acetic anhydride in pyridine at room temperature overnight and GC on a column packed with 6% QF-1 (250°), 5% SE-30 (250°C) or 3% NPGA (225°C). 

Ghosh et al. reported that the chiral oxazolidinone 87, derived from (1S,2R)-cis-l-amino-2-indanol (86), underwent a highly diastereoselective. vyn-aldol reaction with a variety of aldehydes30 (Scheme 2.1cc). Reaction of the indanolamine 86 with disuccinyl carbonate in acetonitrile gave the oxazolidinone 87, which was deprotonated with -BuLi and reacted with propionyl chloride to provide the N-propionyl derivative 88. Reaction of 88 with n-BioBOTf and... 

The three alkaloids named in the title (XXXII, XXXIII, and XXXIV) are respectively the A -formyl, -acetyl, and -propionyl derivatives of aspidospermidine (Section II, E). Demethoxypalosine (XXXIV) has been isolated from Aspidosperma limae (40) and A. discolor (40a) and was characterized as an iVa-acyldihydroindole by its UV-spectrum (Table III) and IR-absorption at 5.89 p. A strong band in the IR-spectrum at 13.1 p indicated an unsubstituted benzene ring. The foregoing information was confirmed and the substance was shown to belong to the aspidospermine group by NMR- and mass spectrometry. In the NMR-spectrum (Table IV) the 17-proton absorption is found at 8.13 well downfield from the three-proton multiplet due to the other aromatic protons which is centered at 7.07 8. This shift is due to the proximity of the carbonyl group of the iVa-propionyl group. In the aliphatic part of the spectrum, absorptions which are characteristic of the... 

In the preparation of these compounds it is found that a better yield and a purer product results by working in a neutral or slightly acid solution. Condensation is effected by heating the reactants for a few hours at a moderate temperature. For the formyl compound, formic acid may replace water as solvent, and for the butyryl and propionyl derivatives the addition of copper turnings shortens the time of heating. With the exception of the latter derivative, these compounds do not contain water of crystallisation, but their salts do contain varying amounts of water. 

Indolealkylamines. GC-MS methods applied in studies of the biochemical pharmacology of indoleamines parallel work on the catecholamines. SIM assays for serotonin (5-hydroxytryptamine), 5-methoxytryptamine, JV-acetylserotonin and melatonin (5-methoxy-N-acetyltryptamine) in rat pineal and brain tissue have been described [453,469]. Pentafluoro-propionyl derivatives and structural homologue standardisation were employed with detection limits in the subpicomole range. Estimation of central indoleamine turnover in man currently depends upon metabolite determination in CSF. Ion monitoring determination of indole-3-acetic acid [454] a metabolite of tryptamine, and isotope dilution assays for 5-hydroxyindoleacetic acid (5-HIAA) [455,458] have been reported. Serotonin is converted by central monoamine oxidase to 5-HIAA and the measurement of this metabolite, formerly by fluorimetry, is of interest in patients with CNS disorders [470]. GC-MS has also contributed to the identification of N,N-dimethyltryptamine in vitro [471] and isotope dilution technique has been applied to the measurement of this metabolite in control subjects and in psychiatric patients [472]. 

Rokitamycin (6) is a semi-synthetic derivative of leucomycin Aj (5), another of the individual factors found in the leucomycin complex along with josamycin (leucomycin Aj). Initially referred to as TMS-19-Q, rokitamycin is the 3"-0-propionyl derivative of leucomycin A5 Figure 5.2) [32, 33]. 

The ethyl derivative, however, was not isolated in a pure form it was always contaminated by traces of solvent. Then, in 1963, Davison et al. (14) reported the synthesis of the ethyl and propionyl derivatives. The ethyl compound was isolated in a pure form from the treatment of Na[Re(CO)s] with ethyl iodide. [Re(C2H5)(CO)s] was also found to be much less susceptible to carbonylation than [Mn(C2H5)(CO)5] and was therefore considerably more stable the reaction between [Re(C2H5)(CO)5] and CO (100 atm) to form [Re(COC2H5)(CO)5] was still not complete after 1 hour at 100°C (14). 

In agreement wth the higher stability of 5d metal derivatives with respect to their 4d homologues, a reaction similar to (n), carried out with an iridium(I) complex, gave the stable propionyl derivative of reaction (p), which was isolated and characterized ... 

Stability of the acyl species Mn(COR) (CO)j, relative to the corresponding alkyl derivatives, decreased in the sequence Et > Me > Ph > CH2Ph (in 2,2 -diethoxydiethyl ether, T = 303 K). The acyl derivative is apparently favored by electron-releasing groups similar to the results obtained with platinum(II) (11.3.2.1.3). The propionyl derivative is so stable that attempts to purify the ethyl derivative led to Mn(COEt)(CO)5, from adventitious carbon monoxide. 

Mo( 7 -C5H5)Et(CO)3 undergoes carbon monoxide insertion under pressure of CO (100 atm) at room temperature. Among its products is a propionyl derivative ... 

Asymmetric aldol reactionsThe enolate of the N-propionyl derivative of 1 can undergo highly syn-selcctivc aldol reactions to provide the non-Evans syn-aldols (16, 48). 

Both in vitro and in vivo activity is reduced by an increase in the acyl group length in the 2 -0-acyl derivatives. The MIC values of the 2 -0-acetyl and 2 -0-propionyl derivatives are nearly the same as that of the parent antibiotic. Because the 2 -0-acyl is easily hydrolyzed in aqueous solution, the potent antibacterial activity has been explained by the hydrolysis of 2 -0-acyl group during bioassays. For this reason, the 2 -hydroxyl group has been considered to be one of the functional groups essential for the biological activity of the macrolide. 

Among the 9-hydroxyl acylated derivatives, the acetyl and propionyl derivatives showed the same degree of antibacterial activity as the parent antibiotics. The in vitro antibacterial activity of the 9,2 -di-0-acyl derivatives from the leucomycin... 

This putative new concept can account for the reason why rokitamycin acts as a bactericidal agent against susceptible cells despite the fact that " C-labeled rokitamycin Ki = 3.4 X 10" M), a 3"-0-propionyl derivative of leucomycin Aj, has about half as much affinity for the ribosome as erythromycin = 1.6 x 10" M) does. In fact, " C-labeled rokitamycin is hardly replaced by nonlabeled rokitamycin, when the labeled drug had previously been bound to ribosomes from susceptible S. aureus [34, 51]. 

Maridomycin III, in which both ester groups are propionyl derivatives, is the principal component of the maridomycin complex elaborated by a valine resistant mutant of Streptomyces hydroscopicus (the six components differ depending on whether acetyl, propionyl, or isovaleryl ester groups are present). The... 

A-Acetyl-4-hydroxy-w-arsanilic acid (Acetarsol, 3-acetamido-4-hydroxyphenylar onic acid) [97-44-9] M 275.1, m 240-250 , pKj 3.73, pKj 7.9, pKj 9.3. It crystallises from water in colourless prisms. It decomposes slowly on prolonged boiling in H2O or dilute alkalis. The N-propionyl derivative recrystallises from H2O with m 228-229 (dec). [Raiziss Fisher Chem Soc 48 1323 1926, Hewitt King J Chem Soc 823 1926, Beilstein 16 I 491,16II521,16 HI 1129.]... 

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