Nonane, structure

In the previous chapter benzomorphan analgesics were considered. They may be thought of as sterically constrained piperidines bearing an axial aromatic ring. Without the fused aromatic ring a 2-azabicyclo[3.3.1]nonane structure (1) remains for which the trivial name morphan was suggested by Robinson/0... 

One of the most popular methods for creating the anatoxin-a skeleton is by transannular cyclization of a suitably substituted cyclooctene. This approach was used in the first synthesis of racemic anatoxin-a (Campbell et al. 1979). They carried out two different methodologies in order to reach the 9-azabicyclo[4.2.1]nonane structure (Scheme 7.3). The 1,5-cyclooctadiene (10) starting compound was transformed into the methyl amine 11 which was treated with hypobromous acid to produce the desired bicycle 12 as a mixture of diastereoisomers in 29% overall yield, with some amount of the azabicyclo[3.2.1] analogue (Bastable etal. 1972). 

Scheme 7.5. Electrocyclic aperture of cyclopropane affording the 9-azabicyclo[4.2.1 ]nonane structure, (a) excess AgOTs, CH3CN, A, 60%. (b) HBr, Benzene, hv. (c) Et3N, CH3CN, A, 32%.

However, such chelation effects are not always observed. For example, in the Woodward erythromycin A synthesis (equation 99), the facial preference of aldehyde (151) is that predicted by application of Cram s rule, even though there is an alkoxy group at the -position. Addition to a chelated carbonyl group in this case would amount to a choice between addition to the convex or concave face of a bi-cyclo[4.3.0]nonane structure (equation 111). 

The expanded capabilities of this catalyst allowed the construction of additional ring systems [44]. A transannular olefin insertion formed a bicyc-lo[3.3.1]nonane structure (Eq. 69). Multiple insertion steps can selectively transform a monocyclic substrate into a propellane derivative (Eq. 70). The catalytic cycle begins at the monosubstituted olefin, followed by the insertion of the remaining double bonds to form five membered rings. 

Hydrolysis of 2-mercaptoethyldichloroarsine (323) or 2-mercaptoethylarsine sulfide (324) with dilute aqueous ammonia formed a colorless product which was assigned the 9-oxa-2,6-dithia-l,5-diarsabicyclo[3.3.1]nonane structure (325) (Scheme 58). 

This compound was shown not to be a complete novelty by the preparation of Ru6(CO)i7C (94, 211, 324) and the arene-substituted derivatives Rue(CO)i4(arene)C (211). The latter were obtained by refluxing Rug(CO)i2 in the appropriate arene (mesitylene, m-xylene, or toluene) or by reaction of the arene with the hexanuclear cluster. Ru6(CO)i7C was obtained by refluxing Ru3(CO)i2 in a variety of high-boiling inert solvents such as octane and nonane. Structural studies revealed the position of the carbon atom, in this case at the center of the regular octahedron or ruthenium atoms and equidistant from all six of them (296, 349) (Fig. 3). 

Darensbourg DJ, Ortiz CG, Kamplain JW (2004) A new water-soluble phosphine derived from l,3,5-triaza-7-phosphaadamantane (PTA), 3,7-diacetyl-l,3,7-triaza-5-phosphabicyclo[3.3.1] nonane. Structural, bonding, and solubility properties. Organometallics 23 1747-1754... 

A certain carboxylic acid (C14H26O2) which can be isolated from whale blubber or sardine oil yields nonanal and 0=CH(CH2)3C02H on ozonolysis What is the structure of this acid" ... 

These procedures proposed by Dubinin and by Stoeckli arc, as yet, in the pioneer stage. Before they can be regarded as established as a means of evaluating pore size distribution, a wide-ranging study is needed, involving model micropore systems contained in a variety of chemical substances. The relationship between the structural constant B and the actual dimensions of the micropores, together with their distribution, would have to be demonstrated. The micropore volume would need to be evaluated independently from the known structure of the solid, or by the nonane pre-adsorption method, or with the aid of a range of molecular probes. 

Bicyclo[3.3.1]nonan-9-one is another ketone that exhibits interesting stereoselectivity. Reduction by hydride donors is preferentially syn to electron-attracting substituents at C-5 (X = EWG in the structure shown below) and anti to electron-releasing substituents (X = ERG below). These effects are observed even for differentially substituted phenyl... 

One after the other, examine structures for octane-1,8-dioic acid, nonane-1,9-dioic acid djud decane-1,10-dioic acid. Is there any difference (in structure or conformation) between the diacids with lower and higher melting points Which, if any, of the acids adopt structures similar to that of acetic acid dimer Account for the variation in melting points of these three compounds. 

Spirapril (37) is a clinically active antihypertensive agent closely related structurally and mechanistically to enalapril. Various syntheses are reported with the synthesis of the substituted proline portion being the key to the methods. This is prepared fkim l-carbobenzyloxy-4-oxopro-line methyl ester (33) by reaction with ethanedithiol and catalytic tosic acid. The product (34) is deprotected with 20% HBr to methyl l,4-dithia-7-azospiro[4.4 nonane-8-carboxylate (35), Condensation of this with N-carbobenzyloxy-L-alanyl-N-hydroxysuccinate leads to the dipeptide ester which is deblocked to 36 by hydrolysis with NaOH and then treatment with 20% HBr. The conclusion of the synthesis of spirapril (37) follows with the standard reductive alkylation [11]. 

When the valence tautomeric mixture of oxepin and benzene oxide is treated with singlet oxygen, the primary product is the 1,4-endoperoxide 3 which has proven to be too labile for isolation.219 Its formation can be rationalized by a 1,4-addition across the diene system of the benzene oxide structure 3 then rearranges to ba s-3,6,9-trioxatetracyclo[6.1.0.02 4.05 ]nonane (transbenzene trioxide, 4). 

The potential of Fischer carbene complexes in the construction of complex structures from simple starting materials is nicely reflected in the next example. Thus, the reaction of alkenylcarbene complexes of chromium and tungsten with cyclopentanone and cyclohexanone enamines allows the di-astereo- and enantioselective synthesis of functionalised bicyclo[3.2.1]octane and bicyclo[3.3.1]nonane derivatives [12] (Scheme 44). The mechanism of this transformation is initiated by a 1,4-addition of the C -enamine to the alkenylcarbene complex. Further 1,2-addition of the of the newly formed enamine to the carbene carbon leads to a metalate intermediate which can... 

Draw stick structures to represent each of the following molecules (a) nonane, CH3(CI l2)-CI I3 (b) cyclopropane,... 

A priori borataethenes would be expected to be much more stable than the corresponding boraethenes because, as Rundle presciently noted about organometallic structures,50 all low-lying atomic orbitals are involved in the bonding. In fact, the stabilization of 52 is the driving force for the acidity of C—H bonds of proper orientation a to tricoordinate boron. Such acidity was first detected by Rathke and Kow through the treatment of B-methyl-9-borabicyclo[3.3.1] nonane (53) with hindered lithium amides, such as lithium 2,2,6,6-tetramethylpiperidide51 (Eq. 18) ... 

An enormous variety of solvates associated with many different kinds of compounds is reported in the literature. In most cases this aspect of the structure deserved little attention as it had no effect on other properties of the compound under investigation. Suitable examples include a dihydrate of a diphosphabieyclo[3.3.1]nonane derivative 29), benzene and chloroform solvates of crown ether complexes with alkyl-ammonium ions 30 54>, and acetonitrile (Fig. 4) and toluene (Fig. 5) solvates of organo-metallic derivatives of cyclotetraphosphazene 31. In most of these structures the solvent entities are rather loosely held in the lattice (as is reflected in relatively high thermal parameters of the corresponding atoms), and are classified as solvent of crystallization or a space filler 31a). However, if the geometric definition set at the outset is used to describe clathrates as crystalline solids in which guest molecules... 

In 1979 the bieyclic diol exo-2,ejco-6-dihydroxy-2,6-dimethylbicyclo[3.3.1]nonane (i) was prepared and observed to co-crystallise with various solvents, including ethyl acetate, chloroform, toluene, dioxane, and acetone. A crystal structure determination of the ethyl acetate compound revealed the occurrence of a helical canal host structure, containing ethyl acetate as guest (with 3 1 diol ethyl acetate stoichiometry), and that spontaneous resolution had occurred on crystallisation of the multimolecular inclusion compound 6>. 

Fig. 4. Diagrammatic representation of layered crystal structures of rigid diols, with closed hydrogen bonding cycles. Open circles are oxygen atoms, filled circles hydrogen atoms, and the solid lines represent the connecting diol. Hydrogen bonds are shown as broken lines, (a) The structure of 2,6-dihydroxy-2,6-dimethyltricyclo[3.3.1.13,7]decane (4). (b) The structure of erafo-2,e do-6-dihydroxy-2,6-dimethylbicyclo[3.3.1]nonane, (7)...

It is no coincidence that the first X-ray structure analysis of a transition metal-boryl complex [8] was made on the iridium complex jac-[IrH2(BC8Hi4)(PMe3)3] (2) [9] derived from the B—H activation of the 9-borabicyclo[3.3.1]-nonane (9-BBN)... 

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