1.2.3- Trienes 1,3-dienes

The complexes [LCo(p-02)(p-OH)CoL] [L = en, trien, dien, tetra-ethylenepentamine, or tris-(2-aminoethyl)amine] have been studied, and the new complexes [[Co(imidazole)(gly)2 202],4H20 [ Co2(imidazole)2-(gly)402 0H],3H20, and [Co(imidazole)(gly)2(02)H20] have been prepared The spectroscopic properties of various p-peroxo- and p-superoxo-cobalt(iii) complexes have been examined. The singly-bridged p-peroxo-compounds have a strong band at 300 nm, whereas this falls at 350 nm for p-peroxo-p-hydroxo-complexes and two peaks at 480 and 700 nm are observed for p-superoxo-species. The i.r. spectra of p-peroxo-bridged complexes of cobalt(iii)-cyclam have been reported. ... 

METHOD SOURCE MATERIAL TRIENE DIENE MONOENE... 

CH2 6,7-epoxylinalool 3,7-dimethylocta-l,7-/ -mentha-l,8-diene-4-ol p-mentha-l,3,8-triene diene-3,6-diol... 

Jote 2. We have also carried out this synthesis in ethanol as a solvent but the results were not reproducible. Although a series of experiments with zinc powder from one flask gave reasonable results (50-78% yields), a new flask with the same batch number gave low yields of impure products. The main impurity was probably the non-conjugated diene, H2C=CH-CH2-CH=CH-CH3, possibly resulting from reduction of the 1,2,4-triene by the zinc. The... 

The achiral triene chain of (a//-rrans-)-3-demethyl-famesic ester as well as its (6-cis-)-isoiner cyclize in the presence of acids to give the decalol derivative with four chirai centres whose relative configuration is well defined (P.A. Stadler, 1957 A. Escherunoser, 1959 W.S. Johnson, 1968, 1976). A monocyclic diene is formed as an intermediate (G. Stork, 1955). With more complicated 1,5-polyenes, such as squalene, oily mixtures of various cycliz-ation products are obtained. The 18,19-glycol of squalene 2,3-oxide, however, cyclized in modest yield with picric acid catalysis to give a complex tetracyclic natural product with nine chiral centres. Picric acid acts as a protic acid of medium strength whose conjugated base is non-nucleophilic. Such acids activate oxygen functions selectively (K.B. Sharpless, 1970). 

Irradiation of steroidal 3,7-dienes with ultraviolet light may result in ring opening and formation of various trienes. The most important reaction of this type is the conversion of ergosterol to previtamin Dj. 

Diene carboxylates can be prepared by the reaction of alkenyl halides with acrylates[34]. For example, pellitorine (30) is prepared by the reaction of I-heptenyl iodide (29) with an acrylate[35]. Enol triflates are reactive pseudo-halides derived from carbonyl compounds, and are utilized extensively for novel transformations. The 3,5-dien-3-ol triflate 31 derived from a 4,5-unsaturated 3-keto steroid is converted into the triene 32 by the reaction of methyl acrylate[36]. 

Dienes, trienes, etc. 1650 (s) and 1600 (s) Lower-frequency band usually more intense and may hide or overlap the higher-frequency band... 

Heteroatom functionalized terpene resins are also utilized in hot melt adhesive and ink appHcations. Diels-Alder reaction of terpenic dienes or trienes with acrylates, methacrylates, or other a, P-unsaturated esters of polyhydric alcohols has been shown to yield resins with superior pressure sensitive adhesive properties relative to petroleum and unmodified polyterpene resins (107). Limonene—phenol resins, produced by the BF etherate-catalyzed condensation of 1.4—2.0 moles of limonene with 1.0 mole of phenol have been shown to impart improved tack, elongation, and tensile strength to ethylene—vinyl acetate and ethylene—methyl acrylate-based hot melt adhesive systems (108). Terpene polyol ethers have been shown to be particularly effective tackifiers in pressure sensitive adhesive appHcations (109). 

Figure 11.15. Typical chemical groupings in a sulphur-vulcanised natural rubber network, (a) Monosulphide cross-link (b) disulphide cross-link (c) polysulphide cross-link (j = 3-6) (d) parallel vicinal cross-link (n = 1-6) attached to adjacent main-chain atoms and which have the same influence as a single cross-link (e) cross-links attached to common or adjacent carbon atom (f) intra-chain cyclic monosulphide (g) intra-chain cyclic disulphide (h) pendent sulphide group terminated by moiety X derived from accelerator (i) conjugated diene (j) conjugated triene (k) extra-network material (1) carbon-carbon cross-links (probably absent)...

Ai.4.6 Triene-3-ones are usually obtained by DDQ dehydrogenation of A -diene-3-ones. The latter are accessible in a variety of ways from A -3-ols or A -3-ketones. This example illustrates a one pot reaction. 

With l,4,6-triene-3-ones, addition occurs exclusively at the 1,2-double bond to yield la-methyl-A -S-ketones. Grignard reaction and reacetylation of 17)5-acetoxyandrosta-l,4,6-trien-3-one (23) gives the la-methyl-4,6-dien-3-one (24) in a crude yield of 85%. ° ... 

A solution of diazomethane in 2.4 liters ether, prepared from 177 g (1.71 moles) of A-nitrosomethylurea and 530 ml of 40% aqueous potassium hydroxide, is added to 26.4 g (0.81 moles) 17 -acetoxyandrosta-1,4,6-triene-3-one in 250 ml ether. After 6 days at room temperature the ether is removed by distillation at reduced pressure and the residue is chromatographed on 1.5 kg of silica gel (deactivated with water 10% v/w). The product is eluted with methylene dichloride and recrystallized from diisopropyl ether-methylene dichloride to give 11 g (37 %) 17 -acetoxyandrosta-4,6-dien-3-one-[2a,la-c]-A -pyrazoline mp 161° (dec.) —91° (CHCI3) ... 

Acetoxy-ta,2a-methy/enandrosta-4.6-dien-3-one and 17[3-Acetoxy-1-methy/androsta-1,4,6-trien-3-one ... 

Addition of dimethylsulfoxonium methylide has also been studied in the retro steroid (9, 10a) series. Results are somewhat different from observations in the normal series. Thus only the 6, 7)3-methylene adduct is obtained from a 4,6-dien-3-one while 6-chloro-9) ,10a-l,4,6-trien-3-ones undergo attack at the 6,7-double bond in preference to the 1,2-double bond resulting in the formation of 6a-chloro-6)5,7i5-methylene-A -3-ones. ... 

Treatment of dichlorocyclopropane (35) first with pyridine to give chloro-diene (36) followed by potassium /-butoxide affords 1-ethoxycyclohepta-1,3,5-triene (37) in 55% overall yield from dichlorocarbene adduct (35). 

Extension of the above method to 3-methoxyestra-3,5(10)-dien-17-one 17-ethylene ketal (46) prepared by base-catalyzed isomerization of 3-methoxy-estra-2,5(10)-dien-17-one 17-ketal (42) with potassium t-butoxide in dimethyl sulfoxide gives the isomeric tropone A-homo-estra-l,4,5(10)-triene-3,17-dione... 

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