3.5- Dinitrobenzoyl deriv

Amino Aliphatic Carboxylic Acids. 3,5-Dinitrobenzoyl derivatives (p. 381), Benzoyl derivatives (p. 382), Sulphonyl derivatives (p. 382). 

Purified by recrystn from aqueous MeOH. It is estimated colorimetrically with H3PO4 in EtOH followed by vanillin and HCl [Hayward and Seymour i4/w/ Chem 20 572 1948]. The 3,5-dinitrobenzoyl derivative has m 92-93°. [J Am Chem Soc 83 3114 7967.]... 

Before an asymmetric synthesis appeared of levofloxacin (1, (—)-ofloxacin), (—)- ofloxacin was isolated via optical, enzymatic, and crystallization resolution of the racemic ofloxacin (17) Drugs Future, 1992 Hayakawa et al., 1986, 1991). For instance, tricyclic core 52 was converted to ( + )-3,5-dinitrobenzoyl derivative 54 in 75% yield (Scheme 4.5). The enantiomers were then separated via high-performance liquid chromatography (HPLC) with a SUMIPAX OA-4200 column to deliver optically pure benzoyl esters 55a and 55b (Drugs Future, 1992 Hayakawa et al., 1986, 1991). 

When the unsaturated Y-benzoyl a-amino ester 443 was treated with MCPBA, the oxirane 444 formed first immediately underwent an intramolecular rearrangement with cleavage of the oxirane ring by attack of the amide oxygen to give a 3 1 mixture of two cis- and /ra r-isomers of 5,6-dihydro-47/-l,3-oxazine derivatives 445 and 446, the configurations of which were determined via their 0-3,5-dinitrobenzoyl derivatives (Scheme 85) <2003M69>. 

Reversed-phase hplc has been used to separate PPG into its components using evaporative light scattering and uv detection of their 3,5-dinitrobenzoyl derivatives. Acetonitrile—water or methanol—water mixtures effected the separation (175). Polymer glycols in PUR elastomers have been identified (176) by pyrolysis-gc. The pyrolysis was carried out at 600°C and produced a small amount of ethane, C02, propane, and mostly propylene, CO, and CH4. The species responsible for a musty odor present in some PUR foam was separated and identified by gc (Supelco SP-2100 capillary column)... 

The separation of enantiomers can be effected either by transforming them into diastereoisomers using a chiral reagent and separating them on conventional phases or by separating the enantiomers on chiral phases. The utilization of chiral phases has not yet become routine, but studies of enantiomeric dipeptides have been carried out (115,116). Pirkle et al. (117) and Hyun et al. (118) separated enantiomeric di- and tripeptides (methyl esters of /V-3-5-dinitrobenzoyl derivatives) on chiral stationary phases (CSPs) derived from (R)-a-arylalkylamines, (S)-N-(2-naphthyl) valine, or (S)-1 -(6,7-dimethyl-1 -naphthyl) isobutylamine. These workers were able to separate four peaks for each dipeptide derivative, corresponding to the two enantiomeric pairs (R,R)/(S,S) and (R,S)/(S,R). Cyclodextrin-bonded stationary phases and chiral stationary immobilized a-chymotrypsin phases were used to separate enantiomeric peptides (118a,b). 

Fig. 7 Correlation between the logarithm of the retention time of the 3,5-dinitrobenzoyl derivatives of PG molecular species expressed in min (log RT) and the corrected equivalent carbon number ECN. (Reprinted from Ref. 89 with the permission of the American Oil Chemists Society.)...

High-performance LC is also a suitable method for separating BHA isomers. Commercially available BHA is a mixture of two positional isomers, an approximately 85 15 ratio of 3-BHA and 2-BHA. The former is approximately 2.4 times more effective as a food antioxidant than is 2-BHA, and half as effective as an inhibitor of benzo(a)pyrene-induced for stomach neoplasia in mice. For the separation, Ansari (116) used isocratic elution with 7% of 2-propanol in hexane on a Pirkle Type I-A column packed with 5- 01 y-aminopropyl packing, modified with lV-3,5-dinitrobenzoyl derivative of D-phenylglycine. Column eluent was monitored at 288 nm, with a detection limit between 1 and 2 ng. Under these conditions, isomers were separated without derivatization, where the phenolic group of 3-BHA was sterically hindered by an o-rm-butyl group and therefore could not interact with stationary phase that resulted in its rapid elution. 

Analytical Properties Separation of 3,5-dinitrobenzoyl derivatives of amino acids 3,5-dinitroanilide derivatives of carboxylic acids Reference 19... 

Acetoxymethyl-7,8-difluoro-2,3-dihydro-4H-[l,4]benzoxazine (m.p. 73-74°C) was synthesized by hydrogenation of a compound prepared from 2,3-difluoro-6-nitrophenol, l-acetoxy-3-chloro-2-propane and potassium iodide. The hydrogenation was carried out on Raney nickel. The resulting compound was dissolved in THF, and 3,5-dinitrobenzoyl chloride and pyridine were added thereto, followed by heating at 60°C for 3 hours. The mixture was concentrated, and the concentrate was dissolved in ethyl acetate, washed successively with diluted hydrochloric acid, an aqueous solution of sodium bicarbonate and water, dried over anhydrous sodium sulfate and concentrated. Addition of n-hexane to the concentrate caused precipitation of yellow crystals of a racemate. The yield of 3,5-dinitrobenzoyl derivative of the ()-3-acetoxymethyl-7,8-difluoro-2,3-dihydro-4H-[l,4]benzoxazine 3.93 g. 

To 2.0 ml of Amberlite XAD 7 was added 2.0 ml of a 0.05 M phosphoric acid buffer (pH 7.0) having dissolved therein 20 mg of lipoprotein lipase, and the system was allowed to stand at room temperature for 18 hours to thereby adsorb the enzyme onto the resin. The resin was filtered. A solution of 250 mg of 3,5-dinitrobenzoyl derivative of ()-3-acetoxymethyl-7,8-difluoro-2,3-dihydro-4H-[l,4]benzoxazine as a substrate in 25 ml of a mixed solvent of benzene and n-hexane (4 1 by volume) was added to the resin, followed by... 

In 135 ml THF was dissolved 3.03 g of a 3,5-dinitrobenzoyl derivative of (-)-3-acetoxymethyl-7,8-difluoro-2,3-dihydro-4H-[l,4]benzoxazine, and 135 ml of ethanol and 30 ml of 1.0 N potassium hydroxide were added to the solution. After 30 min 3 ml of acetic acid was added thereto for neutralization. The mixture was concentrated. The solid was subjected to column chromatography using 40 g of silica gel and eluted with chloroform/methanol to obtain 1.17 g of (-)-7,8-difluoro-2,3-dihydro-3-hydroxymethyl-4H-[l,4]benzoxazine [a]D22 = -14.1° (c = 1.80, CHCI3). 

Three chiral stationary phases that were prepared by derivatizing y-mercaptopropylsilanized silica gel with quinine (CSP II), quinidine (CSP III), and cinchonidine (CSP IV), have been used for the successful resolution of N-acyl derivatives of fl-hydroxyphenethylamines [25]. UV and CD detectors set at 270 nm were used in series. The effectiveness of the separation and the detection are illustrated in Figure 6 for the resolution of the N-(3,5-dinitrobenzoyl) derivative of phenylethanolamine on CSP III. 

Figure 6. The resolution of N-(3,5-dinitrobenzoyl) derivative of phenylethanolamine on the CSP III. Eluant is hexane/2-propoanol/acetonitrile, 80/20/5 (v/v/v). Absorption (A) and CD (0) detection at 270nm. (From Ref. 24).

Another type of CSP able to undergo charge transfer interaction is the one developed by Lindner s group [101], In order to determine the interactions between the quinine CSP and the enantiomeric analytes, a detailed computational study was undertaken of the interaction of this stationary phase with 3,5-dinitrobenzoyl derivatives of leucine (Figure 22-27) [102],... 

Achiral lanthanide chelates can also be added to CSAs such as arylperfluoroalkyl-carbinols, the ethyl ester of 3,5-dinitrobenzoyl-L-leucine (25) , the 3,5-dinitrobenzoyl derivative of 1-phenylethylamine, Af-(l-(l-naphthyl)ethyl)trifluoroacetamide (26) and a series of l-(l-naphthyl)ethyl urea derivatives of amino acids (27) to enhance the enantiomeric discrimination. With sulfoxide or lactone substrates , the europium ion preferentially associates with the substrate in the bulk solution. Provided the enantiomers have different association constants with the CSA, the isomer that shows the weaker association with the CSA shows the larger lanthanide-induced shifts. Low concentrations of lanthanide relative to the substrate and CSA lead to enhancements of enantiomeric discrimination in the NMR spectrum. If the concentration of lanthanide is too high, binding of the substrate to the lanthanide strips the substrate from the chiral solvating agent and diminishes the chiral discrimination in the NMR spectrum. 

Dinitrobenzoyl derivatives of chiral alcohols and amines, trbger base, benzoin, binaphthol, etc,... 

Type I CSPs have also been used with aqueous mobile phases. Pirkle et al. (32) have reported on the resolution of N-(3,5-dinitrobenzoyl) derivatives of M-amino adds and 2-aminophosphonic adds on an (l )-N-(2-naphthyl)-alanine-derived CSP using a mobile phase composed of methanol-aqueous phosphate buffer. The utility of achiral alkyltrimethylammoruum ion-pairing reagents was also investigated. Other examples include the following (1) The recently commercialized ot-Burke 1 CSP resolves the enantiomers of a number of underivatized p-blockers using an ethanol-dichlorornethane-ammonium acetate mobile phase (33) (2) an (R)-l-naphthylethylurea CSP was used to resolve N-(3,5-dinitrobenzoyI)-substituted amino adds and 3,5-dinitrobenzoyl amide derivatives of ibuprofen, naproxen, and fenoprofen with acetonitrile-sodium acetate mobile phases (34). 

La Torre, F., Sinibaldi, M. High-performance liquid chromatography on chiral packed microbore columns with the 3,5-dinitrobenzoyl derivative of trans-1,2-diaminocyclohexane as selector,... 

Embree, L. McErlane, K.M. Electrochemical detection of 3,5-dinitrobenzoyl derivatives of digoxin by high-performance liquid chromatography. J.Chromatogr, 1990, 626, 439-446... 

ULMO 3,5-dinitrobenzoyl derivs donor—widely used ... 

Leucine 3,5-dinitrobenzoyl derivs Ti-electron acceptor REGIS... 

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