Unsaturated analogs

This electron delocalization stabilizes a conjugated system Under conditions cho sen to bring about their mterconversion the equilibrium between a p 7 unsaturated ketone and an a p unsaturated analog favors the conjugated isomer... 

Health and Safety Factors. Butanediol is much less toxic than its unsaturated analogs. It is neither a primary skin irritant nor a sensitizer. Because of its low vapor pressure, there is ordinarily no inhalation problem. As with all chemicals, unnecessary exposure should be avoided. The LD q for white rats is 1.55 g/kg. 

The fully unsaturated tricyclic compounds are also used clinically as antidepressants. Carbamazepine (62), for example, is prepared from 10,ll-dihydro-5H-dibenz[b,f]azepine (49) by N-acetylation followed by bromination with W-bromosuccinimide to give 60. Dehydrohalogenation by heating in collidine introduces the double bond. Saponification with potassium hydroxide in ethanol leads to dibenz[b,f]azepine (61), the parent substance for the fully unsaturated analogs. Treatment of the secondary... 

It is of interest to note that treatment (23) of the 2,3-unsaturated analog 44 with sodium benzoate in 2V,N-dimethylformamide affords compounds 45 and 46 (3 1) with inversion at C-4. The selective formation... 

Similarly, halo-acetoxylation is known. This reaction has also been carried out on triple bonds, to give the unsaturated analogs of 85 (syn addition). ... 

In contrast to the related organoboranes, which are mostly used in the addition to non-polar carbon-carbon multiple bonds, aluminum hydrides have found their widest use in organic synthesis in the addition reaction to polar carbon-carbon and carbon-heteroatom multiple bonds including carbonyl, nitrile and imino groups as well as their a,(J-unsaturated analogs. Although these reduction reactions are also sometimes referred as hydroalumination reactions in the Hterature, they are outside the scope of this review. 

Cobalt complexes of the fused 7-membered ring unsaturated analogs of the dibenzo-[14] tetraazaannulenes, the tropocoronands (H2TC), have also been reported. The crystal structure... 

An explanation for the dehydrogenation process has been offered (Scheme 13). An alkylrhodium intermediate can undergo a /3-elimination process to afford the unsaturated analog A, which is carbonylated by the usual process. 

The 5-iodo derivative 1016 was prepared by reaction of the acetate of 999 with iodine monochloride, and subsequent deprotection using sodium methoxide in methanol. The protected derivative 1016 is a suitable precursor for use in cross-coupling reactions to prepare the unsaturated analogs 1018 and 1019. Thus, reaction of 1016 with methyl acrylate in the presence of palladium(II) acetate gave the ( )-5-(2-methoxycarbonylvinyl)uracil 1017 this was converted into the ( )-5-(2-bromovinyl) analog 1019 by alkaline... 

Moreover, octahydro compounds arise from the reduction (see Section 4.3) of higher unsaturated analogs, such as 8/9b/9d, 124a (see Scheme 32), 319a (see Scheme 71) or 374a and b (see Scheme 85), from the dehydration (see Section 4.4.3) of carbinol 24 or from the carbonylation (see Section 4.4.1) of enamine 133 (see Scheme 34). 

In an earlier investigation by the authors (1) biodegradable poly(ester-amides) were prepared and used as drug delivery devices for internally administered bioactive agents. Unsaturated analogs, (II), were prepared by Chu et al. (2). 

CH2=CH—CH2—CM3 structure, i.e., an unsaturated analog of butylidyne, the possible source of the absorptions from non-7t-bonded vinyl listed above for Ni/Si02 and Co/Si02. 

The reaction of ketocarbenoids with alkynes is a direct method for the synthesis of functionalized cyclopropenes.1 122 123 Until quite recently copper catalysis was generally used and the reactions proceeded in fairly moderate yields, except with terminal alkynes, which failed to generate cyclopropenes due to competing C—H insertions.1 This limitation could be circumvented, however, by using trimethylsilyl derivatives. This approach is illustrated in the synthesis of (131), the unsaturated analog of 1-aminocy-clopropanecarboxylic acid, the biosynthetic precursor to ethylene in plants (Scheme 27).124 The initial... 

The purpose of the present paper is to compare the toxicity and pharmacology of saturated compounds with their unsaturated analogs (wherever possible) and to list some important, physiologically active substances, bearing one or more double bonds. 

As a rule the unsaturated analogs are more toxic. There are some exceptions diethylbenzene20 and divinylbenzene19 (Table 1), 1,1,2-trichloroethane13 and 1,1,2-trichloroethy-lene13 (Table 2), 2-propanol25 and acetone16 (Table 9) etc. 

These alkaloids were isolated, along with their unsaturated analogs (see Section II,B,4), from Cissampelos ovalifolia D.C., an alleged component of Mac-ushi curare, and characterized in 1970 by chemical interrelation and MS studies. At that time it was shown that the three bases have the same skeleton,... 

Unsaturated analogs of DDT are generally transformed to expoxides by liver enzymes, stored in adipose tissue, or further metabolized to... 

Fig. 17 Epothilone trans 2,3 unsaturated analog packs carbon 3 within the receptor s hydrophobic interior and projects the C1 lactone toward the polar exterior...

When the same conditions are applied to oxirane 5 azido alcohol 17 is formed this can be selectively reduced with triphenylphosphine to give amino alcohol 18 in good yield (Scheme 6.4.8 Eq. 2) [11, 25, 26], This compound and other, related, epoxides are a new approach to the chemistry of aminocarbasugars and their unsaturated analogs such as valienamine [27]. 

Salaun, J.P., Weissbart, D., Helvig, C., Durst, F., and Mioskowski, C, Regioselective hydroxylation and epoxidation of lauric acid and unsaturated analogs by cytochrome P450 in Jerusalem artichoke microsomes, Plant Physiol. Biochem., 31, 285-293, 1993. 

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