Angelate ester

Saponification of 0-tigloylcyclovirobuxeine-D (132), isolated from B. sem-pervirens, gives tiglic acid and cyclovirobuxeine-B (133). The n.m.r. spectrum shows features of Buxus alkaloids containing a A double-bond and indicates that the compound is a tiglic ester, and not an angelic ester which has isomerised in alkaline medium. 

The unsaturated angelate ester (7) has been isolated from Brichellia guate-maliensis Complete details of the double Claisen-Cope rearrangement... 

The most frequent combination of the MGL is with an epoxy group (n=545). Combination of an MGL with a tiglic/angelic ester, occurs 424 times. In the majority of MGL-containing compounds (n=1827) this PRS is not combined with either GLE, EPOX, or TA. Of these structures, 1300 do not contain a combination with any other of... 

Orabi, K.Y, 2001. Microbial epoxidation of the tricyclic sesquiterpene presilphlperfolane angelate ester. Z. Naturforsch., 56C 223-227. 

Furthermore, when no base is present during esterification, double bonds are also little affected, as Greene showed when converting a variety of alcohols to angelate esters (12) in quantitative yield standard esterification procedures gave a mixture of angelate and tiglate esters (eq 8). ... 

Alkannin occurs in the roots of the plant as the alkah-sensitive ester of angelic acid (62). It may be extracted from the roots by using boiling light petroleum ether. Treatment of this extract with dilute sodium hydroxide gives a blue solution from which the dye is precipitated by the addition of acid. The cmde product is purified by vacuum sublimation (63). Its stmcture (11) is a hydroxylated naphthoquinone with a long, unsaturated side chain (64,65) it has the (3)-configuration. 

The hydrogenation of the esters methyl tiglate, methyl trifluorotiglate, and methyl angelate occurred slowly over 1% Pd/SiOa at room temperature and 10 bar pressure. Modification of the catalyst by cinchonidine or cinchonine induced no enantioselectivity under any conditions Typical results are given in Table 2. 

Other Novel Solvents. In addition to molecules based on carboxylic and carbonic esters, other types of organic polar compounds were also explored as possible solvent candidates but with limited success. Zhang and Angell synthesized a dimeric glycol ester of boric ester (BEG, Table 12) in... 

Sonobe, H., Kamps, L.R., Mazzola, E.P., and Roach, J.A.G. Isolation and identification of a new conjugated carbofuran metabolite in carrots angelic acid ester of 3-hydroxycarbofuran, /. Agric. Food Chem., 29(6) 1125-1129, 1981. 

Cunninghamella blakesleana affords the 7/3-hydroxy-, 16a-hydroxy-, 16,17-dihydroxy-, and 7/3,16a-dihydroxy-derivatives. The angelic acid ester of ent-15/3-hydroxykaur-16-en-19-oic acid (73) and its 16,17-epoxide (perymenic acid) have been obtained from Perymenium ecuadoricum (Compositae). A group of... 

Esters of benzenoid and monoterpenic acids and alcohols as well as unsaturated carboxylic acids such as tiglic acid 142 and angelic acid 143 (Structure 4.43) are found in essential oils [60, 61]. 

Lactones are cyclic esters derived from lactic acid (CsHeOs). They are constituents of many essential oils and plant volatiles. They contain a heterocyclic oxygen next to a carbonyl function in a five or more membered ring that is saturated or unsaturated. Those with a five-membered ring are called y-lactones, e.g. y-angel-ica lactone 148, whereas compounds containing a six-membered ring are called (5-lactones, e.g. (5-valerolactone 149 (Structure 4.45) [1-4, 6, 9, 22, 23,29, 62]. 

Uniperox 60. A proprietary mixt of cyclic hydrocarbon hydroperoxides contg 6 to 8 C atoms. Its avg mw is 130, which corresponds to the empirical formula C7H1302H. The commercial product, manufd by the R.T. Collier Corp, Los Angeles, Cal, is a water-white liq contg 60—65% by wt of hydroperoxide in admixt with ales and ketones of about the same boiling range. Its d is 0.96g/cc mp —80° bp (decompn at 110°) flash pt 80° sol in w 0.5% by wt and is completely miscible with ales, ethers, ketones, esters and petroleum fractions... 

Figure 5.62). Several of these hydroxyls are ester-ifled with aliphatic acids, e.g. acetic, tiglic, and angelic acids. 

Kawamura and Kaplan [482] have described a sensitive method for measuring volatile acids (Ci-C7) in rain and fog samples using /j-bromophcnacyl esters and a high resolution capillary gas chromatograph employing fused silica columns. Experiments showed that the measured concentrations of volatile acids in spiked rain samples increased linearly in proportion to the concentrations of volatile acids added. Relative standard deviations were less than or equal to 18% for Q, C2 and C3 acids. The distributions of volatile acids in Los Angeles rain and fog samples are discussed. 

Roman esters of angelic and tiglic acids (up to 85%), and pinene, farnesol, nerolidol, pinacarvone, cineole. 

---