Polycyclic derivatives

Polycyclic derivatives have been prepared by straightforward amide formation. The tetracyclic amide 166 was obtained by reductive cyclization of 3-o-nitrophenylindole-2-carboxylic acid (165).22 When l-(2 -ethoxycarbonylskatyl)isoquinoline (167) was heated the pentacyclic j8-carboline derivative 168 was formed. If,... 

In addition to the parent compound 2, the derivatives 2a, b, the benzo-system 16, the lactone-peroxides 17, and the fused polycyclic derivatives 18 and 19 could be prepared via the singlet oxygen-diimide route. For example, the parent system 2 was obtained in ca. 40% yield by diimide reduction of the stable 1,3-cyclohexadiene endoperoxide in MeOH at 0 °C27,28). Dihydroascaridole 2a and dihydroergosterol endoperoxide... 

The inclusion complexes of 3-R 4-R2-disubstituted l,2,5-oxadiazole-2-oxide with polycyclic derivatives of gluco-pyranose were prepared by heating an aqueous ethanolic solution of /3-cyclodedextrin with the corresponding furazan... 

Head-to-tail intramolecular dimerization of nonactivated vinyl groups can also occur in compounds in which the tether is only two atoms long under conditions of flash-vacuum pyrolysis (FVP). Under such conditions strained bridged polycyclic derivatives can be prepared.78 The formation of 18 is the result of intramolecular head-to-tail cycloaddition of the Cope rearrangement intermediate derived from 1,2-divinylacenaphthene.78... 

One bond in substituted cubanes was cleaved oxidatively by thionyl chloride to yield polycyclic derivatives of dichlorocyclohexanes in 86-92% yield.147... 

Likewise, polycyclic derivatives of bicyclo[4.2.0]octane-l,6-diol were oxidized by periodate to give derivatives of cyclooctane-1,4-dione.37,157... 

Similarly, in polycyclic derivatives of tricyclo[5.3.0.02-6]decane a [2 + 2] cycloreversion gave derivatives of cyclodeca-1,6-diene in 25-90% yield on flash-vacuum pyrolysis at 600 °C.208- 209... 

Methylquinoxaline is reported to give a polycyclic derivative (117) related to quinoxaline orange with 2-equivalents of tetrachloro-1,2-ben zoquinone 2-(2-quinoxalino)-4,5,6,7-tetrachlorobenzo-1,3-dioxole... 

Parent monocyclic Polycyclic derivatives OH-Substituted derivatives NH2-Substituted derivatives compounds... 

In addition to their work on tricyclic systems, Chmielewski and co-workers have used monosaccharides to obtain polycyclic derivatives of oxacepham. For instance, cyclization of 479 (R2 = Tos or TIBS) in a two-phase system including a phase-transfer catalyst and potassium carbonate gave 480 in 65-90% yields. The protecting group R1 was lost if it was a silyl group, for example, TMS, TBDMS <1998T14065>. 

One further unique diarylstannylene which is worth discussing in more detail is the polycyclic derivative (22)34. This particular molecule possesses three divalent Sn atoms, two of them being coordinated by two amido ligands and the remaining one by two aryl substituents. The Sn atom (SnA) of the bis(aryl)stannylene fragment shows no unusual tight contacts to any other atom — there are close intramolecular contacts to the other Sn atoms, but they are most probably superimposed by the geometric needs of a bicyclic... 

Monocyclic compounds Polycyclic derivatives OH-substituted derivatives NH substituted derivatives ... 

Annular tautomers are prototropic tautomers in which the migrating proton is restricted to ring atoms. For these five-membered heterocycles, annular tautomerism can only occur with pyrrole 2 and its polycyclic derivatives. There is no authenticated case of the monocyclic pyrrolenine tautomeric forms 211 and 212 predominating, presumably due to the required loss of resonance energy in these nonaromatic tautomers . 

This reaction also gave the opportunity to open an access to various polycyclic derivatives, as illustrated by the transformation of the mixture of diaster eomers 133 into tricyclic derivative 134 as a single diastereomer, thanks to a completely stereoconvergent process. An interesting entry into carene 136 and carone derivatives 137 has also been disclosed by Fiirstner [88]. 1,5-Enynes have proven to be versatile precursors for the preparation of perfumery agents such as sabina ketone (Scheme 45). 

In another approach, Arya et al. [58] describe solution and solid-phase synthesis of two polycyclic derivatives, 22.2 and 22.3 (Figure 15.22), from enantiopure... 

Polycyclic derivatives, such as diaza-adamantane and tetraaza-tricyclodo-decanc 139, may also be synthesized. 

Fig. 69. Simultaneous rearrangement-ring forming aminomcthylation reaction leading to polycyclic derivatives.

Cyclic diketoncs and primary amines also yield other interesting polycyclic derivatives of types 117 and... 

First, 2-pyrrol-1-yl-benzaldchyde 159 (Fig. 55), which combines in the same molecule the functions of both substrate and aldehyde, gives aminoalkylation in position 2 of the pyrrole ring by reaction with the secondary amine, thus yielding an interesting precursor (160) of polycyclic derivatives with fused nuclei. ... 

Other polycyclic derivatives have been obtained, for instance polycylohex-anes via multiple 6-endo-trig cyclizations [30] as in the formation of 19 from 18 (Scheme 6) [31]. 

Bis(Boc)tryptophan methyl ester, on treatment with A -phenylselcnophthalimide (/V-PSP) underwent cyclization leading in good yield to the polycyclic derivative 9 as an inseparable 90 10 diastereomeric mixture (exo/endo), following the equilibration of an initial 50 50 mixture232. 

The Pd-catalyzed intramolecular arylation involving C (sp2)-H activation gave a library of fused pyridoimidazoquinolinones (iii). The green synthesis afforded the polycyclic derivatives in good yields [8]. 

There is no settled convention for the representation of polyacetals and other complex cyclic derivatives of carbohydrates. To facilitate the comparison of polycyclic derivatives of carbohydrates with alicyclic compounds, the carbohydrate derivatives will be drawn in perspective, with single rings and fused rings placed in the plane of the paper, and with darkened or broken lines used to show the orientation of substituents and bridges above or below the plane of the rings, respectively, as is customary for terpenes and steroids. 

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