Substituted derivatives of

Mono-anionic ligand derivatives [Rh6(CO)i5L] (L = H, halide or pseudo halide) also have the structure shown in Fig. 5a NMR measurements (Table 3) show that their structure in solution is consistent with their static structure and, apart from [HRh6(CO)i5] , vide infra, are non-fluxional at room temperature. 

The stereochemically most favorable structure for [Rh6(CO)i4L2] is shown in Eig. 5b and, when L = P(OPh)3, is the structure adopted in the solid state and in solution. There are, however, four other isomers which are theoretically possible and there is chromatographic and spectroscopic evidence for two of these isomers when L = P(OPh)3. P COSY measurements and simulations suggest that these are the next two least sterically hindered isomers. Both of these isomers, on heating, are transformed into the thermodynamically more stable isomer shown in Pig. 5b. When L = py or NCMe, separation into individual isomers was impossible because of their rapid interconversion.  

No structural/NMR data have been reported for the species [Rh6(CO)i3L3j. This is probably because of the number of stereochemically similar isomers and the problems associated with their separation. 

The structure which minimizes steric interactions for [Rh6(CO)i2L4] is shown in Fig. 5c and is found by X-ray analysis when L = P(OPh)3. Multinuclear ( C, 3ip, i03j jjj ]sj]y[R (jata show that the solid-state structure is retained in solution at room temperature. 

Bidentate ligand derivatives [Rh6(CO)i6 jc(LL)jc (LL = bidentate, 4-electron donor jc = 1-3) 

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CeH5N(CH3)H + C SO C,H, -> CeH5N(CH3)S02C6H5 + HCl mono-and di-substituted derivatives of benzenesulphonamide, C6H5SO2NH2 and thus termed benzenesulphonphenylamide, and benzenesulphon-methylphenylamide respectively. Sulphonylation, like benzoylation, can there-... 

Substitution Derivatives of Ethyl Malonate, Ethyl malonate resembles ethyl acetoacetate in that it gives rise to mono- and di-substituted derivatives in precisely similar circumstances. Thus when ethanolic solutions of ethyl malonate and of sodium ethoxide are mixed, the sodium derivative (A) of the enol form is produced in solution. On boiling this solution with an alkyl halide, e.g, methyl iodide, the methyl derivative (B) of the keto form is obtained. When this is treated again in ethanolic solution with sodium ethoxide, the... 

Barbituric acid and 2-thiobarbituric acid are readily prepared by the condensation of diethylmalonate with urea and thiourea respectively, in the presence of sodium ethoxide. The use of substituted derivatives of urea and thiourea and of diethyl malonate will clearly lead to a wide range of barbituric and thiobarbituric acids having substituents in the i, 3, or 5 positions. 

It should be noted that only representative substances are indicated in the above list. Substituted derivatives of the compounds in most classes may be encountered, e.g., nitrobenzoic acid in the aromatic carboxylic acids (p. 347). This acid will contain CH(0)N, but the salient properties are still those of a carboxylic acid, CH(0), Section 14, although the properties of an aromatic nitro-compound (e.g.y reduction to an amino-compound) will also be evident. 

The mono-alkyl C-substituted derivatives of ethyl acetoacetate upon treatment with sodium ethoxide and another molecule of alkyl halide afford the di-alkyl C-substituted products... 

Certain ortho substituted derivatives of aromatic amines are difficult to acetylate under the above conditions owing to steric hindrance. The process is facilitated by the addition of a few drops of concentrated sulphuric acid (compare Section IV,47), which acts as a catalyst, and the use of a large excess of acetic anhydride. 

The imides, primaiy and secondary nitro compounds, oximes and sulphon amides of Solubility Group III are weakly acidic nitrogen compounds they cannot be titrated satisfactorily with a standard alkaU nor do they exhibit the reactions characteristic of phenols. The neutral nitrogen compounds of Solubility Group VII include tertiary nitro compounds amides (simple and substituted) derivatives of aldehydes and ketones (hydrazones, semlcarb-azones, ete.) nitriles nitroso, azo, hydrazo and other Intermediate reduction products of aromatic nitro compounds. All the above nitrogen compounds, and also the sulphonamides of Solubility Group VII, respond, with few exceptions, to the same classification reactions (reduction and hydrolysis) and hence will be considered together. 

TABLE 5.2 Nitrations of mono-substituted derivatives of benzene in solutions of acetyl nitrate in acetic anhydride ... 

There have been many studies of the orientation of nitration in di- and poly-substituted derivatives of benzene, but in very few cases have... 

The lUPAC rules name branched alkanes as substituted derivatives of the unbranched alkanes listed in Table 2 2 Consider the CgHi4 isomer represented by the structure... 

Write structural formulas or build molecular models and give the lUPAC names of all the monochloro substituted derivatives of cyclopentene... 

All compounds that contain a benzene ring are aromatic and substituted derivatives of benzene make up the largest class of aromatic compounds Many such compounds are named by attaching the name of the substituent as a prefix to benzene... 

On the other hand an alkyl side chain on a benzene nng is oxidized on being heated with chromic acid The product is benzoic acid or a substituted derivative of benzoic acid... 

Many aromatic compounds are simply substituted derivatives of benzene and are named accordingly Many others have names based on some other parent aromatic compound... 

The scope of electrophilic aromatic substitution is quite large both the aromatic com pound and the electrophilic reagent are capable of wide variation Indeed it is this breadth of scope that makes electrophilic aromatic substitution so important Elec trophilic aromatic substitution is the method by which substituted derivatives of benzene are prepared We can gam a feeling for these reactions by examining a few typical exam pies m which benzene is the substrate These examples are listed m Table 12 1 and each will be discussed m more detail m Sections 12 3 through 12 7 First however let us look at the general mechanism of electrophilic aromatic substitution... 

Organometallic compounds are named as substituted derivatives of metals The metal is the parent and the attached alkyl groups are identified by the appropriate prefix... 

The second molar equivalent of the alkyllithium adds to the alkylcopper to give a neg atively charged dialkyl substituted derivative of copper(I) called a dialkylcuprate It is formed as its lithium salt a lithium dialkylcuprate... 

Ethylene oxide is a very reactive substance It reacts rapidly and exothermically with anionic nucleophiles to yield 2 substituted derivatives of ethanol by cleaving the car bon-oxygen bond of the nng... 

As we ve just seen nucleophilic ring opening of ethylene oxide yields 2 substituted derivatives of ethanol Those reactions involved nucleophilic attack on the carbon of the ring under neutral or basic conditions Other nucleophilic ring openings of epoxides like wise give 2 substituted derivatives of ethanol but either involve an acid as a reactant or occur under conditions of acid catalysis... 

We name compounds of the type RCNHR and RCNR2 as N alkyl and N N dialkyl substituted derivatives of a parent amide... 

Amines which are substituted derivatives of ammonia react similarly O O... 

Aniline is the parent lUPAC name for ammo substituted derivatives of benzene Substituted derivatives of aniline are numbered beginning at the carbon that bears the ammo group Substituents are listed m alphabetical order and the direction of number mg IS governed by the usual first point of difference rule... 

Secondary and tertiary amines are named as N substituted derivatives of primary amines The parent primary amine is taken to be the one with the longest carbon chain The prefix N is added as a locant to identify substituents on the ammo nitrogen as needed... 

A/-Methylethylamine (given as CH3NHCH2CH3 in the pre ceding example) is an N substituted derivative of ethanamine it is A/-methyl ethanamine... 

Recall from Section 24 1 that cresols are methyl substituted derivatives of phenol... 

Focants of substituents of symmetrically substituted derivatives of symmetrical amines are distinguished by primes or else the names of the complete substituted radicals are enclosed in parentheses. Unsymmetrically substituted derivatives are named similarly or as A-substituted products of a primary amine (after choosing the most senior of the radicals to be the parent amine). For example. 

Substituted derivatives of nickelocene, where one ring has been replaced, include the complex cyclopentadienyl nitrosyl nickel [12071 -73-7], (7T-C3H3)NiNO, a red Hquid, mp -41°C. A review of nitrosyl complexes with nickel is available (89). The dimer complex... 

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