Isobutyryl derivatives

The benzoyl derivative is the more rapidly formed, but on standing it is slowly and irreversibly converted into the salt of the isobutyryl derivative. 

A reaction yield of 46% with an ee of 97% was obtained for the N-isobutyryl derivative (+)-44. The undesired isomer (-)-42b was recovered from the resolution step, race-mized, and resubjected to enzymatic acylation to increase material throughput. A mixture of (->42b (100 g, 83.0% ee) and diethyleneglycol dibutyl ether (500 mL) was heated at 210°C under N for 18 h to obtain complete racemization [98]. 

A simple aniline derivative acts as a prostatic antiandro-t (>n. Its synthesis involves simple acylation of disubstituted iiriiline 13 with isobutyryl chloride to give flutamide (14). 

Isobutylene, reaction with chlorosul fonyl isocyanate, 46, 52 Isobutyryl fluoride, 45, 6 Isocyanates, acyl, derivatives of, 46, 17... 

The mixture of free amino acids is reacted with OPA (Fig. 7-8) and a thiol compound. When an achiral thiol compound is used, a racemic isoindole derivative results. These derivatives from different amino acids can be used to enhance the sensitivity of fluorescence detection. Figure 7-9 shows the separation of 15 amino acids after derivatization with OPA and mercaptothiol the racemic amino acids may be separated on a reversed-phase column. If the thiol compound is unichiral, the amino acid enantiomers may be separated as the resultant diastereomeric isoindole compound in the same system. Figure 7-10 shows the separation of the same set of amino acids after derivatization with the unichiral thiol compound A-isobutyryl-L-cysteine (IBLC). 

First the interaction of selected tetramethylpiperidine (TMP) derivatives with radicals arising from Norrish-type I cleavage of diisopropyl ketone under oxygen was studied. These species are most probably the isopropyl peroxy and isobutyryl peroxy radicals immediately formed after a-splitting of diisopropyl ketone and subsequent addition of O2 to the initially generated radicals. Product analysis and kinetic studies showed that the investigated TMP derivatives exercise a marked controlling influence over the nature of the products formed in the photooxidative process. The results obtained point to an interaction between TMP derivatives and especially the isobutyryl peroxy radical. 

OPA in combination with chiral thiols is one method used to determine amino acid enantiomers. A highly fluorescent diastereomeric isoindole is formed and can be separated on a reverse-phase column. Some of these chiral thiols include N-acetyl-L-cysteine (NAC), N-tert-butyloxy-carbonyl- L-cysteine (Boc-L-Cys), N-isobutyryl- L-cysteine (IBLC), and N-isobutyryl- D -cysteine (IBDC). Replacing OPA-IBLC with OPA-IBDC causes a reversal in the elution order of the derivatives of D- and L-amino acids on an ODS column (Hamase et al., 2002). Nimura and colleagues (2003) developed a novel, optically active thiol compound, N-(tert-butylthiocarbamoyl)- L-cysteine ethyl ester (BTCC). This reagent was applied to the measurement of D-Asp with a detection limit of approximately 1 pmol, even in the presence of large quantities of L-ASP. 

Di-iso-butyryl Peroxide (called Diisobutyryl-peroxyd in Ger), (CH3)2CH.CO.OO.CO.CH(CH3)2 mw 174.19, O 36.74% gas, dec vigorously at 110-20° (20° higher than the n-butytyl deriv) when heated in a tube (Ref 2) was prepd by reacting isobutyryl chloride with Na peroxide in cold eth or petr eth (Ref 1). Smid Szwarc (Ref 3) studied its kinetics of decompn Refs 1) Beil 2, 653l 2) A.E. Oxford, JCS... 

Compounds 110 and 111 from Ekebergia benguelensis are resveratrol derivatives with an isobutyryl substituent [65], while idenburgene (112)... 

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