Acyl Substituted Derivatives

When PhMn(CO)s reacts with trans-1,3-pentadiene, and the resulting acyl substituted derivative 68 heated to 120°C (0.1 mm Hg), loss of carbon monoxide leads to a 73% yields of 69 [Eq. (32)] (226). Recently a derivative 70 of the parent ligand has been prepared from (Ph3P)2ReH7 and furan under reflux in thf, in the presence of 3,3 -dimethyl-1-butene as hydrogen acceptor (227). 

The role of the nature of the reagent (depended on reaction conditions) reveals itself most distinctly in the fact that acylation of N-(phenylsulfonyl)pyrrole in the presence of aluminum chloride results in the 3-acyl-substituted derivatives, while the reaction in the presence of boron trifluoride etherate gives the 2-isomers (83JOC3214) (Scheme 24). 

It is interesting to note that only 6-acyl-substituted derivatives can be transformed in this way, but not nonacylated purine bases. ... 

The derivative Ph3P=NEt hydrolyses instantly in cold water, but Ph3P=N COOEt requires several minutes in boiling acid for hydrolysis. Alkyl compounds R3P=NR are colourless liquids which can be distilled at reduced pressures without decomposition, but N-acyl substituted derivatives R3P=N C(0)R decompose at 150-200°C to alkyl cyanides and phosphine oxides. 

CARBOXYLIC ACID DERIVATIVES NUCLEOPHILIC ACYL SUBSTITUTION... 

Carboxylic Acid Derivatives Nucleophilic Acyl Substitution... 

Both stages involve more than one step and these steps differ in detail among the various carboxylic acid derivatives and for different reaction conditions This chapter is organized to place the various nucleophilic acyl substitutions into a common mechanis tic framework and to point out the ways m which individual classes differ from the rest... 

Conversions of acid anhydrides to other carboxylic acid derivatives are illustrated m Table 20 2 Because a more highly stabilized carbonyl group must result m order for nucleophilic acyl substitution to be effective acid anhydrides are readily converted to carboxylic acids esters and amides but not to acyl chlorides... 

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