Esterification, crotonic acid

Crotonic acid, esterification with sec-butyl alcohol, 41, 60 Crystal Violet, from condensation of oxalyl chloride with dimethyl-aniline, 41, 2-4... 

A new acidic esterification has been reported in which a carboxylic silyl ester is condensed with an alcohol under the action of p-trifluoromethylbenzoic anhydride and a combination of HfCU and AgOTf as catalyst (Eq. 15). The esters are obtained in high yields even if almost equimolar amounts of substrates are employed. The method is applicable to the esterification of a,j8-enoic acids, such as crotonic acid, which is often hampered by side reactions, e.g. E Z isomerization, deconjugation, and the Michael reaction [21a,b]. 

Phorbol (14) was isolated from the oil of Croton tiglium (Euphorbiaceae) seeds " ". The presence of a system containing both the cyclopropanol and the cyclopropylcarbinol functionalities at the C/D ring moiety is quite unusual. Various fatty acid esters of phorbol have been shown to be the active components responsible for the co-carcinogenic activity of croton oil. Esterification usually occurs at C(11) and C(12) with a pair of long chain and short chain fatty acids, as in the potent co-carcinogenic tetradecyl phorbol acetate (TPA). 

Asymmetric conjugate addition of RiCuLij The chiral crotonyl ester 1, prepared from (+ )-camphor by addition of 1-naphthylmagnesium bromide followed by esterification with crotonic acid, undergoes conjugate addition with BuaCuLi at -25° to give the adduct 2 in 95% de. Reduction of 2 with LiAUtj gives (S)-3-... 

Esterification, crotonic acid, 149 levulinic acid, 157 thiophene-2-carboxylic acid, 182 o-toluic acid, 162 Ester interchange, 152 Ethanolysis of ethyl iminoacetate, 159 Ether cleavage with HBr, 271... 

In 2015, IFF patented the hydroformylation of cyclopentene (Scheme 6.19) [91]. In turn, the formed aldehyde was reacted with MeMgCl to afford the corresponding secondary alcohol. By esterification with crotonic acid, an ester was obtained having fruity, green, fresh, woody spicy, and sweet notes. 

This procedure is generally applied to the esterification of highly sensitive acids, which might otherwise undergo isomerisation. Thus in the example given, no ethyl crotonate is formed. 

Esterification, of cyanoacetic acid, 41, 5 of gluconolactone, 41, 79 of tetraacetylgluconic acid, 41, 80 of a-d-unsaturated acids, 41, 62 preparation of sec-butyl crotonate by, 41, 60... 

Among five triterpenoids isolated from Calendula officinalis flowers, P-amyrin (119), faradiol (232), i /-taraxasterol (238), taraxasterol (239), and lupeol (238), the diol 232 was the most active. It showed a dose-dependent effect with a potency that equals that of indomethacin (5) in the topical anti-inflammatory assay with croton oil [33]. Esterification at C-3 of 232 with a fatty acid reduced the activity by more than 50% [33] consistent with our observation in the TPA-induced assay described above. The anti-inflammatory properties, as determined by croton oil-induced edema of mouse ear, of faradiol-3-O-myristate (233) and its 3-O-palmitate (234), the main components of lipophilic extracts of C. officinalis flowers, were shown to be contribute significantly to the pronounced antiphlogistic activity of the lipophilic extracts of C. officinalis flowers [34]. 

Binapacryl (29) is a compound with an action weaker than that of dinocap, and was initially also used as an acaricide. Its structural basis is dinoseb (28), which is an active substance with herbicidal properties. Binapacryl is formed by (he esterification of dinoseb with 3-methylcrotonic acid chloride, its chemical composition being 4,6-dinitro-2-jec-butylphenyl-3-methyl crotonate. 

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