2-Methyl- -dienoic acids

A mixture of 10 g of the glyoxylic acid, 100 ml of acetic anhydride, and 0.5 g of 2,4-dinitrobenzenesulfonic acid is stirred at 25° for 2 hr. Sodium acetate (0.5 g) is added and the mixture concentrated in vacuum at 50°. The residue is taken up in 100 ml of benzene and washed with two portions of 2.5 N sodium hydroxide to remove the remaining acetic anhydride. The benzene solution is washed with water, dried and concentrated in vacuum to dryness. Crystallization from 40 ml of absolute ethanol gives 9.8 g (85%) of 3a,20,23-trihydroxy-16a-methyl-11 -oxo-21 -norchola-17(20),22-dienoic acid-24(20)-lactone 3,23-diacetate mp 165-175°. 

Several studies have dealt with the problem of discriminating between mastic and dammar, and three marker compounds of mastic have been identified moronic, masticadienonic and acetyl masticadienolic acids [42], The chemical structure of (iso)masticadienonic acid and 3-0-acetyl-3-epi(iso)masticadienonic acid is characterized by a side chain, as for dammarane molecules, but with a carboxylic acid end group (Table 12.1). Under pyrolysis conditions this side chain is susceptible to cleavage as demonstrated by the presence, among the pyrolysis products of mastic, of 2-methyl-pent-2,4-dienoic acid, that perfectly matches with the chemical structure of the side chain end. In addition 3-(9-acetyl-3-epi-(iso)masticadienolic acid also loses the acetyl group and, in contrast to masticadienonic acid, is not detected at all. 

A convenient way of six-carbon homologation of aldehydes and ketones is the nucleophilic addition of the dianion generated from sorbic acid, (2 ,4 )-hexa-2,4-dienoic acid and subsequent dehydration to form the corresponding trienoic acid (equation 43)81. The 3-methyl analogue of sorbic acid has been used in a similar fashion for a short synthesis of vitamin A carboxylic acid (equation 44)82. 

Enantiomers of 7-methyl-1,6-dioxaspiro [4.5] decane 27 Decan-4-olide (Z,Z)-Octadeca-9,12-dienoic acid... 

Deca-c s-2-trans-4-dienoic acid, 6-iso-propyl-3-methyl-9-oxo cured Lf ... 

Deca-trans-2-trans-4-dienoate, 9-oxo-6-iso-propyl-3-methyl, methyl Lf ° Deca-trans-2-trans-4-dienoic acid, 6-iso-pro-pyl-3-methyl-9-oxo, (-) Lf Deca-trans-2-trans-7-dienoic acid, 6-iso-pro-pyl-3-methyl-9-oxo cured Lf Deca-trans-4-9-dienoic acid, 3-hydroxy-6-iso-propyl-3 -methyl-9-(5-oxo-tetrahydrofuran-... 

Hept-6-en-2-ol, (E) -5 -iso-propyl- 7 - (2-methy-tetrahydro-fur-2-yl) Lf Hept-6-en-2-one, (E)-5-iso-propyl-7-(2-methyl-tetrahydro-fur-2-yl) Lf Hepta-4-(E)-6-dienoic acid, 3-iso-propyl-6-methyl, methyl ester Cured Lf 0.075 Hepta-4-6-dien-l-ol, 3-iso-propyl-6-methyl, (E) Lf ... 

Oct-2-en-4-olide, 3-methyl-7-oxo Lf 0.003 Octa-5-trans-7-dienoic acid, 4-iso-propyl-7-methyl, methyl ester cured Lf 0.75 Octacosanoic acid ... 

Most recently in 2003, McLeod s group obtained the 3-lactone motif of orlistat (1) using a bromolactonization reaction.3,Y-Unsaturated acid 38 was prepared from a diene-ester, hexadeca-2,4-dienoic acid methyl ester. McLeod et al discovered that conducting the bromolactonization in methanol and 10% aqueous sodium bicarbonate solution afforded predominantly rrany-39, which was then transformed to orlistat (1). 

The technique is also used to introduce diene moieties, which enable the polymer for a highly efficient modification with dienophile components via Diels-Alder reaction [354], Therefore, methyl octa-4,6-dienoate is converted to octa-4,6-dienoic acid hydrazide, which is bound to dextran via reaction with BrCN. The maleimide-modified protein (albumin) is easily attached to the polymer backbone by Diels-Alder reaction (Fig. 50). 

S,4S,5 E,7E)-3-Amino-4-hydroxy-6-methyl-8-(4-bromophenyl)-octa-5,7-dienoic acid [Aboa = Br-Ahmp, Br-Apoa], (2S,3S,8S,9S)-3-Amino-9-methoxy-2,6,8-trimethyl-10-phenyl-deca-4,6-dienoic acid (Adda). 3-Amino-2,4-dimethylpentanoic acid (Admpa). (2S,3R,5S)-3-amino-2,5,9-trihydroxy-10-phenyldecanoic acid (Ahda). j3-Aminoisobutyric acid (jS-AiB). (3S,4S,5E,7E)-3-Amino-4-hydroxy-6-methyl-8-phenylocta-5,7-dienoic acid [Ahmp (Faulkner) or Apoa (Fusetani)]. (2S,3R,5R)-3-Amino-2,5-dihydroxy-8-phenyloctanoic acid (Ahoa). 3-Aminopentanoic acid (Apa /5-Apa). (2R,3R)-3-Amino-2-methylbutanoic add (Amba). 3-Amino-2-methylhexanoic acid (Amha). 3-Amino-2-methyl-7-octynoic add (Amoa, Amoya). 3-Amino-7-octynoic add (Aoya). (2S,3R)-3-Amino-2-methylpentanoic acid (Map). http // www.ncbi.nlm.nih.gov/ Taxonomy/ tax.html... 

Structural investigations on the sex pheromones of male butterflies have yielded several unique insect exocrine products. The major components in the hair pencils of the danaid Lycorea ceres ceres are cetyl acetate, (Z)-vaccenyl acetate, and 2,3-dihydro-7-methyl pyrrolizin-l-one (XXIV) (103) The dihydropyrrol izi none, as well as ( , )-3,7-dimethyldeca-2,6-dien-l,10-diol, have been identified from the hair pencils of the queen butterfly, Danaus gilippus (104), and the former compound possesses pheromonal activity when evaluated electrophysiologically (105) and behaviorally (106). The hair pencils of the monarch butterfly, Danaus plexippus, have yielded ( ,E)-10-hydroxy-3,7-dimethyl-2,6-deca dienoic acid (107) and (E,15)-3,7-dimethyl-2,6-decadien-l,10-dioic acid (108). On the other hand, the Old World monarch, Danaus chrysippus, contains (E)-3,7-dimethyloct-2-en-l,8-diol as well as the pyrrolizinone (XXIV) (109). Recently,... 

The C20 amino acid (2.V,3.S, 8.S, 9.S, 4/ , 6 )-3-amino-9-methoxy-2,6,8-tri-methyl-10-phenyldeca-4,6-dienoic acid (Adda 19) is a molecule of interest to biologists and organic chemists as a component of the hepatotoxic cyclic peptides called microcystins. Kim and Toogood used Ireland-Claisen rearrangement in their successful synthesis of Adda8 (Scheme 1.3h). The ester 20 underwent highly diastereoselective Ireland-Claisen rearrangement to provide the acid 21. Conversion of this acid to the phosphonium bromide 22 was achieved in nine... 

Methyl-(2Z,4E)-dienoic aclds, (2E,4E)-Dienoic acids are available by Wittig-type reactions. A stereospecific synthesis of the less stable (2Z,4E)-isomers from aldehydes uses 1 as the key reagent. Deprotonation of 1 (LDA, -95°) leads to the lithio derivative 2, which reacts with the aldehyde 3, to give, in 72% yield, the 5-lactone 4, which is desulfurized quantitatively to S. Reaction of 5 with potassium <-butoxide is accompanied by elimination to the desired acid 6. 

SYNS DIBUTYISIS((3-CARBOXYACRYLOYL)OXY)-STANNANE DIMETHYL ESTER (Z,Z) (SCI) DIBUTYLTIN BIS(METHYL MALEATE) DIBUTYLTIN BIS(MONOMETHYL MALEATE) DIBUTYLTIN METHYL MALEATE 6,6-DIBUTYL-4,8,lI-TRIOXO-5,7,12-TRIOXA-6-STANNATRlDECA-2,9-DIENOIC ACID METHYL ESTER DI-n-BUTYLZINN-DIMONO-METHYLMALEINAT (GERMAN) STAN-GUARD 156... 

DIBUTYL-4,8,l 1 -TRIOXO-5,7,12-TRIOXA-6-STANNATRIDECA-2,9-DIENOIC ACID METHYL ESTER see BKO250... 

Freshwater cyanobacteria Microcystis, Oscillatoria, Ana-baena, and Nostoc produce several types of toxins, among which the most commonly detected are the hepatotoxic peptides microcystins. The general structure of the microcystins is cyclo-(D-Ala -X -D-MeAsp -Z -Adda -D-Glu -Mdha ), in which X and Z represent variable L-amino acids, D-MeAsp is D-eryf/iro-p-methylaspartic acid, Mdha is A-methyldehydroalanine, and Adda is the unusual C20 amino acid, (25,35,85,95)-3-amino-9-meth-oxy-2,6,8-trimethyl-10-phenyldeca-4( ),6( )-dienoic acid (Fig. 1). The structural differences in the microcystins mainly depend on the variability of the two L-amino acids (denoted X and Z), and secondarily on the methylation or demethylation of D-MeAsp and/or Mdha. More than 60 microcystins have been isolated from bloom samples and isolated strains of cyanobacteria. 

Figure 5.1a (Continued) octadiene-3,6-diol) (11) hydroxycitronellol (3,7-di methyloctane-l,7-diol) (12) 8-hydroxydihydrolinalool (2,6-dimethyl-7-octene-l,6-diol) (13) 7-hydroxygeraniol (E-3,6-dimethyl-2-octene-l,7-diol) (14) 7-hydro-xynerol (Z-3,6-dimethyl-2-octene-l, 7-diol) (15) cis and trans 8-hydroxy linalool (E- and Z-2,6-dimethyl-2,7-octadiene-l,6-diol) (16) p-menthenediol I (p-menth-l-ene-7,8-diol) (17) E-geranic acid (3,7-dimethyl-2,6-octadienoic acid) (18) E-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid (19) E- and Z-sobrerol or p-menthenediol II (p-menth-l-ene-6,8-diol) (20) cis and trans rose oxide (21) nerol oxide (22) 2-exo-hydroxy-1,8-cineol (23) 1,8-cineol (24) wine lactone (25) cis and trans 1,8-terpin (26) triol (2,6-dimethyloctane-2,3,6-triol) (27) hotrienol [(5E)-3,5-dimethylocta-l,5,7-trien-3-ol] (28) myrcenol (2-methyl-6-methylene-7-octen-2-ol)...

In another case, reaction of 3,3-dimethyl-2-phenylcycloprop-l-enecarboxylic acid with p-tolu-enesulfonic acid in refluxing toluene gave (Z)-4-methyl-3-phenylpenta-2,4-dienoic acid. Hydrolysis of 2,3,3-trichlorocyclopropene-substituted acetals gave 2,3-dichloroprop-2-en-1-ones, e.g. reaction of 11. ... 

Octadeca-9,12-dienoic acid methyl ester, (Z,Z) cis-9-cis-12-0ctadecadienoic acid methyl ester... 

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